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  • Using HTML 5 SessionState to save rendered Page Content

    - by Rick Strahl
    HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Problem rendering VBO

    - by Onno
    I'm developing a game engine using OpenTK. I'm trying to get to grips with the use of VBO's. I've run into some trouble because somehow it doesn't render correctly. Thus far I've used immediate mode to render a test object, a test cube with a texture. namespace SharpEngine.Utility.Mesh { using System; using System.Collections.Generic; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL; using SharpEngine.Utility; using System.Drawing; public class ImmediateFaceBasedCube : IMesh { private IList<Face> faces = new List<Face>(); public ImmediateFaceBasedCube() { IList<Vector3> allVertices = new List<Vector3>(); //rechtsbovenvoor allVertices.Add(new Vector3(1.0f, 1.0f, 1.0f)); //0 //rechtsbovenachter allVertices.Add(new Vector3(1.0f, 1.0f, -1.0f)); //1 //linksbovenachter allVertices.Add(new Vector3(-1.0f, 1.0f, -1.0f)); //2 //linksbovenvoor allVertices.Add(new Vector3(-1.0f, 1.0f, 1.0f)); //3 //rechtsondervoor allVertices.Add(new Vector3(1.0f, -1.0f, 1.0f)); //4 //rechtsonderachter allVertices.Add(new Vector3(1.0f, -1.0f, -1.0f)); //5 //linksonderachter allVertices.Add(new Vector3(-1.0f, -1.0f, -1.0f)); //6 //linksondervoor allVertices.Add(new Vector3(-1.0f, -1.0f, 1.0f)); //7 IList<Vector2> textureCoordinates = new List<Vector2>(); textureCoordinates.Add(new Vector2(0, 0)); //AA - 0 textureCoordinates.Add(new Vector2(0, 0.3333333f)); //AB - 1 textureCoordinates.Add(new Vector2(0, 0.6666666f)); //AC - 2 textureCoordinates.Add(new Vector2(0, 1)); //AD - 3 textureCoordinates.Add(new Vector2(0.3333333f, 0)); //BA - 4 textureCoordinates.Add(new Vector2(0.3333333f, 0.3333333f)); //BB - 5 textureCoordinates.Add(new Vector2(0.3333333f, 0.6666666f)); //BC - 6 textureCoordinates.Add(new Vector2(0.3333333f, 1)); //BD - 7 textureCoordinates.Add(new Vector2(0.6666666f, 0)); //CA - 8 textureCoordinates.Add(new Vector2(0.6666666f, 0.3333333f)); //CB - 9 textureCoordinates.Add(new Vector2(0.6666666f, 0.6666666f)); //CC -10 textureCoordinates.Add(new Vector2(0.6666666f, 1)); //CD -11 textureCoordinates.Add(new Vector2(1, 0)); //DA -12 textureCoordinates.Add(new Vector2(1, 0.3333333f)); //DB -13 textureCoordinates.Add(new Vector2(1, 0.6666666f)); //DC -14 textureCoordinates.Add(new Vector2(1, 1)); //DD -15 Vector3 copy1 = new Vector3(-2.0f, -2.5f, -3.5f); IList<Vector3> normals = new List<Vector3>(); normals.Add(new Vector3(0, 1.0f, 0)); //0 normals.Add(new Vector3(0, 0, 1.0f)); //1 normals.Add(new Vector3(1.0f, 0, 0)); //2 normals.Add(new Vector3(0, 0, -1.0f)); //3 normals.Add(new Vector3(-1.0f, 0, 0)); //4 normals.Add(new Vector3(0, -1.0f, 0)); //5 //todo: move vertex normal and texture data to datastructure //todo: VBO based rendering //top face //1 IList<VertexData> verticesT1 = new List<VertexData>(); VertexData T1a = new VertexData(); T1a.Normal = normals[0]; T1a.TexCoord = textureCoordinates[5]; T1a.Position = allVertices[3]; verticesT1.Add(T1a); VertexData T1b = new VertexData(); T1b.Normal = normals[0]; T1b.TexCoord = textureCoordinates[9]; T1b.Position = allVertices[0]; verticesT1.Add(T1b); VertexData T1c = new VertexData(); T1c.Normal = normals[0]; T1c.TexCoord = textureCoordinates[10]; T1c.Position = allVertices[1]; verticesT1.Add(T1c); Face F1 = new Face(verticesT1); faces.Add(F1); //2 IList<VertexData> verticesT2 = new List<VertexData>(); VertexData T2a = new VertexData(); T2a.Normal = normals[0]; T2a.TexCoord = textureCoordinates[10]; T2a.Position = allVertices[1]; verticesT2.Add(T2a); VertexData T2b = new VertexData(); T2b.Normal = normals[0]; T2b.TexCoord = textureCoordinates[6]; T2b.Position = allVertices[2]; verticesT2.Add(T2b); VertexData T2c = new VertexData(); T2c.Normal = normals[0]; T2c.TexCoord = textureCoordinates[5]; T2c.Position = allVertices[3]; verticesT2.Add(T2c); Face F2 = new Face(verticesT2); faces.Add(F2); //front face //3 IList<VertexData> verticesT3 = new List<VertexData>(); VertexData T3a = new VertexData(); T3a.Normal = normals[1]; T3a.TexCoord = textureCoordinates[1]; T3a.Position = allVertices[3]; verticesT3.Add(T3a); VertexData T3b = new VertexData(); T3b.Normal = normals[1]; T3b.TexCoord = textureCoordinates[0]; T3b.Position = allVertices[7]; verticesT3.Add(T3b); VertexData T3c = new VertexData(); T3c.Normal = normals[1]; T3c.TexCoord = textureCoordinates[5]; T3c.Position = allVertices[0]; verticesT3.Add(T3c); Face F3 = new Face(verticesT3); faces.Add(F3); //4 IList<VertexData> verticesT4 = new List<VertexData>(); VertexData T4a = new VertexData(); T4a.Normal = normals[1]; T4a.TexCoord = textureCoordinates[5]; T4a.Position = allVertices[0]; verticesT4.Add(T4a); VertexData T4b = new VertexData(); T4b.Normal = normals[1]; T4b.TexCoord = textureCoordinates[0]; T4b.Position = allVertices[7]; verticesT4.Add(T4b); VertexData T4c = new VertexData(); T4c.Normal = normals[1]; T4c.TexCoord = textureCoordinates[4]; T4c.Position = allVertices[4]; verticesT4.Add(T4c); Face F4 = new Face(verticesT4); faces.Add(F4); //right face //5 IList<VertexData> verticesT5 = new List<VertexData>(); VertexData T5a = new VertexData(); T5a.Normal = normals[2]; T5a.TexCoord = textureCoordinates[2]; T5a.Position = allVertices[0]; verticesT5.Add(T5a); VertexData T5b = new VertexData(); T5b.Normal = normals[2]; T5b.TexCoord = textureCoordinates[1]; T5b.Position = allVertices[4]; verticesT5.Add(T5b); VertexData T5c = new VertexData(); T5c.Normal = normals[2]; T5c.TexCoord = textureCoordinates[6]; T5c.Position = allVertices[1]; verticesT5.Add(T5c); Face F5 = new Face(verticesT5); faces.Add(F5); //6 IList<VertexData> verticesT6 = new List<VertexData>(); VertexData T6a = new VertexData(); T6a.Normal = normals[2]; T6a.TexCoord = textureCoordinates[1]; T6a.Position = allVertices[4]; verticesT6.Add(T6a); VertexData T6b = new VertexData(); T6b.Normal = normals[2]; T6b.TexCoord = textureCoordinates[5]; T6b.Position = allVertices[5]; verticesT6.Add(T6b); VertexData T6c = new VertexData(); T6c.Normal = normals[2]; T6c.TexCoord = textureCoordinates[6]; T6c.Position = allVertices[1]; verticesT6.Add(T6c); Face F6 = new Face(verticesT6); faces.Add(F6); //back face //7 IList<VertexData> verticesT7 = new List<VertexData>(); VertexData T7a = new VertexData(); T7a.Normal = normals[3]; T7a.TexCoord = textureCoordinates[4]; T7a.Position = allVertices[5]; verticesT7.Add(T7a); VertexData T7b = new VertexData(); T7b.Normal = normals[3]; T7b.TexCoord = textureCoordinates[9]; T7b.Position = allVertices[2]; verticesT7.Add(T7b); VertexData T7c = new VertexData(); T7c.Normal = normals[3]; T7c.TexCoord = textureCoordinates[5]; T7c.Position = allVertices[1]; verticesT7.Add(T7c); Face F7 = new Face(verticesT7); faces.Add(F7); //8 IList<VertexData> verticesT8 = new List<VertexData>(); VertexData T8a = new VertexData(); T8a.Normal = normals[3]; T8a.TexCoord = textureCoordinates[9]; T8a.Position = allVertices[2]; verticesT8.Add(T8a); VertexData T8b = new VertexData(); T8b.Normal = normals[3]; T8b.TexCoord = textureCoordinates[4]; T8b.Position = allVertices[5]; verticesT8.Add(T8b); VertexData T8c = new VertexData(); T8c.Normal = normals[3]; T8c.TexCoord = textureCoordinates[8]; T8c.Position = allVertices[6]; verticesT8.Add(T8c); Face F8 = new Face(verticesT8); faces.Add(F8); //left face //9 IList<VertexData> verticesT9 = new List<VertexData>(); VertexData T9a = new VertexData(); T9a.Normal = normals[4]; T9a.TexCoord = textureCoordinates[8]; T9a.Position = allVertices[6]; verticesT9.Add(T9a); VertexData T9b = new VertexData(); T9b.Normal = normals[4]; T9b.TexCoord = textureCoordinates[13]; T9b.Position = allVertices[3]; verticesT9.Add(T9b); VertexData T9c = new VertexData(); T9c.Normal = normals[4]; T9c.TexCoord = textureCoordinates[9]; T9c.Position = allVertices[2]; verticesT9.Add(T9c); Face F9 = new Face(verticesT9); faces.Add(F9); //10 IList<VertexData> verticesT10 = new List<VertexData>(); VertexData T10a = new VertexData(); T10a.Normal = normals[4]; T10a.TexCoord = textureCoordinates[8]; T10a.Position = allVertices[6]; verticesT10.Add(T10a); VertexData T10b = new VertexData(); T10b.Normal = normals[4]; T10b.TexCoord = textureCoordinates[12]; T10b.Position = allVertices[7]; verticesT10.Add(T10b); VertexData T10c = new VertexData(); T10c.Normal = normals[4]; T10c.TexCoord = textureCoordinates[13]; T10c.Position = allVertices[3]; verticesT10.Add(T10c); Face F10 = new Face(verticesT10); faces.Add(F10); //bottom face //11 IList<VertexData> verticesT11 = new List<VertexData>(); VertexData T11a = new VertexData(); T11a.Normal = normals[5]; T11a.TexCoord = textureCoordinates[10]; T11a.Position = allVertices[7]; verticesT11.Add(T11a); VertexData T11b = new VertexData(); T11b.Normal = normals[5]; T11b.TexCoord = textureCoordinates[9]; T11b.Position = allVertices[6]; verticesT11.Add(T11b); VertexData T11c = new VertexData(); T11c.Normal = normals[5]; T11c.TexCoord = textureCoordinates[14]; T11c.Position = allVertices[4]; verticesT11.Add(T11c); Face F11 = new Face(verticesT11); faces.Add(F11); //12 IList<VertexData> verticesT12 = new List<VertexData>(); VertexData T12a = new VertexData(); T12a.Normal = normals[5]; T12a.TexCoord = textureCoordinates[13]; T12a.Position = allVertices[5]; verticesT12.Add(T12a); VertexData T12b = new VertexData(); T12b.Normal = normals[5]; T12b.TexCoord = textureCoordinates[14]; T12b.Position = allVertices[4]; verticesT12.Add(T12b); VertexData T12c = new VertexData(); T12c.Normal = normals[5]; T12c.TexCoord = textureCoordinates[9]; T12c.Position = allVertices[6]; verticesT12.Add(T12c); Face F12 = new Face(verticesT12); faces.Add(F12); } public void draw() { GL.Begin(BeginMode.Triangles); foreach (Face face in faces) { foreach (VertexData datapoint in face.verticesWithTexCoords) { GL.Normal3(datapoint.Normal); GL.TexCoord2(datapoint.TexCoord); GL.Vertex3(datapoint.Position); } } GL.End(); } } } Gets me this very nice picture: The immediate mode cube renders nicely and taught me a bit on how to use OpenGL, but VBO's are the way to go. Since I read on the OpenTK forums that OpenTK has problems doing VA's or DL's, I decided to skip using those. Now, I've tried to change this cube to a VBO by using the same vertex, normal and tc collections, and making float arrays from them by using the coordinates in combination with uint arrays which contain the index numbers from the immediate cube. (see the private functions at end of the code sample) Somehow this only renders two triangles namespace SharpEngine.Utility.Mesh { using System; using System.Collections.Generic; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL; using SharpEngine.Utility; using System.Drawing; public class VBOFaceBasedCube : IMesh { private int VerticesVBOID; private int VerticesVBOStride; private int VertexCount; private int ELementBufferObjectID; private int textureCoordinateVBOID; private int textureCoordinateVBOStride; //private int textureCoordinateArraySize; private int normalVBOID; private int normalVBOStride; public VBOFaceBasedCube() { IList<Vector3> allVertices = new List<Vector3>(); //rechtsbovenvoor allVertices.Add(new Vector3(1.0f, 1.0f, 1.0f)); //0 //rechtsbovenachter allVertices.Add(new Vector3(1.0f, 1.0f, -1.0f)); //1 //linksbovenachter allVertices.Add(new Vector3(-1.0f, 1.0f, -1.0f)); //2 //linksbovenvoor allVertices.Add(new Vector3(-1.0f, 1.0f, 1.0f)); //3 //rechtsondervoor allVertices.Add(new Vector3(1.0f, -1.0f, 1.0f)); //4 //rechtsonderachter allVertices.Add(new Vector3(1.0f, -1.0f, -1.0f)); //5 //linksonderachter allVertices.Add(new Vector3(-1.0f, -1.0f, -1.0f)); //6 //linksondervoor allVertices.Add(new Vector3(-1.0f, -1.0f, 1.0f)); //7 IList<Vector2> textureCoordinates = new List<Vector2>(); textureCoordinates.Add(new Vector2(0, 0)); //AA - 0 textureCoordinates.Add(new Vector2(0, 0.3333333f)); //AB - 1 textureCoordinates.Add(new Vector2(0, 0.6666666f)); //AC - 2 textureCoordinates.Add(new Vector2(0, 1)); //AD - 3 textureCoordinates.Add(new Vector2(0.3333333f, 0)); //BA - 4 textureCoordinates.Add(new Vector2(0.3333333f, 0.3333333f)); //BB - 5 textureCoordinates.Add(new Vector2(0.3333333f, 0.6666666f)); //BC - 6 textureCoordinates.Add(new Vector2(0.3333333f, 1)); //BD - 7 textureCoordinates.Add(new Vector2(0.6666666f, 0)); //CA - 8 textureCoordinates.Add(new Vector2(0.6666666f, 0.3333333f)); //CB - 9 textureCoordinates.Add(new Vector2(0.6666666f, 0.6666666f)); //CC -10 textureCoordinates.Add(new Vector2(0.6666666f, 1)); //CD -11 textureCoordinates.Add(new Vector2(1, 0)); //DA -12 textureCoordinates.Add(new Vector2(1, 0.3333333f)); //DB -13 textureCoordinates.Add(new Vector2(1, 0.6666666f)); //DC -14 textureCoordinates.Add(new Vector2(1, 1)); //DD -15 Vector3 copy1 = new Vector3(-2.0f, -2.5f, -3.5f); IList<Vector3> normals = new List<Vector3>(); normals.Add(new Vector3(0, 1.0f, 0)); //0 normals.Add(new Vector3(0, 0, 1.0f)); //1 normals.Add(new Vector3(1.0f, 0, 0)); //2 normals.Add(new Vector3(0, 0, -1.0f)); //3 normals.Add(new Vector3(-1.0f, 0, 0)); //4 normals.Add(new Vector3(0, -1.0f, 0)); //5 //todo: VBO based rendering uint[] vertexElements = { 3,0,1, //01 1,2,3, //02 3,7,0, //03 0,7,4, //04 0,4,1, //05 4,5,1, //06 5,2,1, //07 2,5,6, //08 6,3,2, //09 6,7,5, //10 7,6,4, //11 5,4,6 //12 }; VertexCount = vertexElements.Length; IList<uint> vertexElementList = new List<uint>(vertexElements); uint[] normalElements = { 0,0,0, 0,0,0, 1,1,1, 1,1,1, 2,2,2, 2,2,2, 3,3,3, 3,3,3, 4,4,4, 4,4,4, 5,5,5, 5,5,5 }; IList<uint> normalElementList = new List<uint>(normalElements); uint[] textureIndexArray = { 5,9,10, 10,6,5, 1,0,5, 5,0,4, 2,1,6, 1,5,6, 4,9,5, 9,4,8, 8,13,9, 8,12,13, 10,9,14, 13,14,9 }; //textureCoordinateArraySize = textureIndexArray.Length; IList<uint> textureIndexList = new List<uint>(textureIndexArray); LoadVBO(allVertices, normals, textureCoordinates, vertexElements, normalElementList, textureIndexList); } public void draw() { //bind vertices //bind elements //bind normals //bind texture coordinates GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.NormalArray); GL.EnableClientState(ArrayCap.TextureCoordArray); GL.BindBuffer(BufferTarget.ArrayBuffer, VerticesVBOID); GL.VertexPointer(3, VertexPointerType.Float, VerticesVBOStride, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, normalVBOID); GL.NormalPointer(NormalPointerType.Float, normalVBOStride, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, textureCoordinateVBOID); GL.TexCoordPointer(2, TexCoordPointerType.Float, textureCoordinateVBOStride, 0); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ELementBufferObjectID); GL.DrawElements(BeginMode.Polygon, VertexCount, DrawElementsType.UnsignedShort, 0); } //loads a static VBO void LoadVBO(IList<Vector3> vertices, IList<Vector3> normals, IList<Vector2> texcoords, uint[] elements, IList<uint> normalIndices, IList<uint> texCoordIndices) { int size; //todo // To create a VBO: // 1) Generate the buffer handles for the vertex and element buffers. // 2) Bind the vertex buffer handle and upload your vertex data. Check that the buffer was uploaded correctly. // 3) Bind the element buffer handle and upload your element data. Check that the buffer was uploaded correctly. float[] verticesArray = convertVector3fListToFloatArray(vertices); float[] normalsArray = createFloatArrayFromListOfVector3ElementsAndIndices(normals, normalIndices); float[] textureCoordinateArray = createFloatArrayFromListOfVector2ElementsAndIndices(texcoords, texCoordIndices); GL.GenBuffers(1, out VerticesVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, VerticesVBOID); Console.WriteLine("load 1 - vertices"); VerticesVBOStride = BlittableValueType.StrideOf(verticesArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(verticesArray.Length * sizeof(float)), verticesArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); if (verticesArray.Length * BlittableValueType.StrideOf(verticesArray) != size) { throw new ApplicationException("Vertex data not uploaded correctly"); } else { Console.WriteLine("load 1 finished ok"); size = 0; } Console.WriteLine("load 2 - elements"); GL.GenBuffers(1, out ELementBufferObjectID); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ELementBufferObjectID); GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(elements.Length * sizeof(uint)), elements, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ElementArrayBuffer, BufferParameterName.BufferSize, out size); if (elements.Length * sizeof(uint) != size) { throw new ApplicationException("Element data not uploaded correctly"); } else { size = 0; Console.WriteLine("load 2 finished ok"); } GL.GenBuffers(1, out normalVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, normalVBOID); Console.WriteLine("load 3 - normals"); normalVBOStride = BlittableValueType.StrideOf(normalsArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(normalsArray.Length * sizeof(float)), normalsArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); Console.WriteLine("load 3 - pre check"); if (normalsArray.Length * BlittableValueType.StrideOf(normalsArray) != size) { throw new ApplicationException("Normal data not uploaded correctly"); } else { Console.WriteLine("load 3 finished ok"); size = 0; } GL.GenBuffers(1, out textureCoordinateVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, textureCoordinateVBOID); Console.WriteLine("load 4- texture coordinates"); textureCoordinateVBOStride = BlittableValueType.StrideOf(textureCoordinateArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(textureCoordinateArray.Length * textureCoordinateVBOStride), textureCoordinateArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); if (textureCoordinateArray.Length * BlittableValueType.StrideOf(textureCoordinateArray) != size) { throw new ApplicationException("texture coordinate data not uploaded correctly"); } else { Console.WriteLine("load 3 finished ok"); size = 0; } } //used to convert vertex arrayss for use with VBO's private float[] convertVector3fListToFloatArray(IList<Vector3> input) { int arrayElementCount = input.Count * 3; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (Vector3 v in input) { output[fillCount] = v.X; output[fillCount + 1] = v.Y; output[fillCount + 2] = v.Z; fillCount += 3; } return output; } //used for converting texture coordinate arrays for use with VBO's private float[] convertVector2List_to_floatArray(IList<Vector2> input) { int arrayElementCount = input.Count * 2; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (Vector2 v in input) { output[fillCount] = v.X; output[fillCount + 1] = v.Y; fillCount += 2; } return output; } //used to create an array of floats from private float[] createFloatArrayFromListOfVector3ElementsAndIndices(IList<Vector3> inputVectors, IList<uint> indices) { int arrayElementCount = inputVectors.Count * indices.Count * 3; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (int i in indices) { output[fillCount] = inputVectors[i].X; output[fillCount + 1] = inputVectors[i].Y; output[fillCount + 2] = inputVectors[i].Z; fillCount += 3; } return output; } private float[] createFloatArrayFromListOfVector2ElementsAndIndices(IList<Vector2> inputVectors, IList<uint> indices) { int arrayElementCount = inputVectors.Count * indices.Count * 2; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (int i in indices) { output[fillCount] = inputVectors[i].X; output[fillCount + 1] = inputVectors[i].Y; fillCount += 2; } return output; } } } This code will only render two triangles and they're nothing like I had in mind: I've done some searching. In some other questions I read that, if I did something wrong, I'd get no rendering at all. Clearly, something gets sent to the GFX card, but it might be that I'm not sending the right data. I've tried altering the sequence in which the triangles are rendered by swapping some of the index numbers in the vert, tc and normal index arrays, but this doesn't seem to be of any effect. I'm slightly lost here. What am I doing wrong here?

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  • Lot's of errors by insserv on apt-get operations after trying to install tomcat

    - by yankee
    I wanted to install tomcat on my Debian 6.0.4 machine. I tried apt-get install tomcat6-user which worked fine. But then I changed my mind about the user installation and wanted to install the package tomcat6. This resulted in a bunch of errors (see below). Now whatever I try to do with apt-get or with aptitude (trying to remove tomcat6-user, trying to remove tomcat6, trying to perform an apt-get upgrade,...) just results in the same list of errors. How did I manage that? And how can I fix it? # apt-get install tomcat6 Reading package lists... Done Building dependency tree Reading state information... Done The following extra packages will be installed: authbind Suggested packages: tomcat6-docs tomcat6-admin tomcat6-examples libtcnative-1 The following NEW packages will be installed: authbind tomcat6 0 upgraded, 2 newly installed, 0 to remove and 32 not upgraded. Need to get 56.6 kB of archives. After this operation, 442 kB of additional disk space will be used. Do you want to continue [Y/n]? Get:1 http://mirror.hetzner.de/debian/packages/ squeeze/main authbind amd64 1.2.0 [17.3 kB] Get:2 http://mirror.hetzner.de/debian/security/ squeeze/updates/main tomcat6 all 6.0.35-1+squeeze2 [39.3 kB] Fetched 56.6 kB in 0s (441 kB/s) Preconfiguring packages ... Selecting previously deselected package authbind. (Reading database ... 34717 files and directories currently installed.) Unpacking authbind (from .../authbind_1.2.0_amd64.deb) ... Selecting previously deselected package tomcat6. Unpacking tomcat6 (from .../tomcat6_6.0.35-1+squeeze2_all.deb) ... Processing triggers for man-db ... Setting up authbind (1.2.0) ... Setting up tomcat6 (6.0.35-1+squeeze2) ... Creating config file /etc/default/tomcat6 with new version Adding system user `tomcat6' (UID 108) ... Adding new user `tomcat6' (UID 108) with group `tomcat6' ... Not creating home directory `/usr/share/tomcat6'. insserv: warning: script 'S99iptables-custom' missing LSB tags and overrides insserv: warning: script 'iptables-custom' missing LSB tags and overrides insserv: There is a loop at service iptables-custom if started insserv: There is a loop between service rmnologin and mountnfs if started insserv: loop involving service mountnfs at depth 6 insserv: loop involving service networking at depth 5 insserv: loop involving service kbd at depth 9 insserv: There is a loop between service rmnologin and mountall-bootclean if started insserv: loop involving service mountall-bootclean at depth 5 insserv: loop involving service mountall at depth 4 insserv: There is a loop between service iptables-custom and lvm2 if started insserv: loop involving service lvm2 at depth 2 insserv: loop involving service udev at depth 1 insserv: There is a loop at service rmnologin if started insserv: There is a loop between service iptables-custom and checkroot if started insserv: loop involving service checkroot at depth 2 insserv: loop involving service keyboard-setup at depth 1 insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Max recursions depth 99 reached insserv: loop involving service courier-imap-ssl at depth 1 insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: loop involving service hwclockfirst at depth 2 insserv: loop involving service mountoverflowtmp at depth 9 insserv: loop involving service checkfs at depth 6 insserv: loop involving service mdadm-raid at depth 4 insserv: loop involving service hostname at depth 3 insserv: There is a loop between service iptables-custom and ifupdown-clean if started insserv: loop involving service ifupdown-clean at depth 5 insserv: There is a loop between service rmnologin and mountall if started insserv: There is a loop between service iptables-custom and mountdevsubfs if started insserv: loop involving service mountdevsubfs at depth 1 insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: loop involving service mtab at depth 6 insserv: There is a loop between service rmnologin and mountoverflowtmp if started insserv: Starting iptables-custom depends on rmnologin and therefore on system facility `$all' which can not be true! insserv: exiting now without changing boot order! update-rc.d: error: insserv rejected the script header dpkg: error processing tomcat6 (--configure): subprocess installed post-installation script returned error exit status 1 configured to not write apport reports Errors were encountered while processing: tomcat6 E: Sub-process /usr/bin/dpkg returned an error code (1)

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  • 256 Windows Azure Worker Roles, Windows Kinect and a 90's Text-Based Ray-Tracer

    - by Alan Smith
    For a couple of years I have been demoing a simple render farm hosted in Windows Azure using worker roles and the Azure Storage service. At the start of the presentation I deploy an Azure application that uses 16 worker roles to render a 1,500 frame 3D ray-traced animation. At the end of the presentation, when the animation was complete, I would play the animation delete the Azure deployment. The standing joke with the audience was that it was that it was a “$2 demo”, as the compute charges for running the 16 instances for an hour was $1.92, factor in the bandwidth charges and it’s a couple of dollars. The point of the demo is that it highlights one of the great benefits of cloud computing, you pay for what you use, and if you need massive compute power for a short period of time using Windows Azure can work out very cost effective. The “$2 demo” was great for presenting at user groups and conferences in that it could be deployed to Azure, used to render an animation, and then removed in a one hour session. I have always had the idea of doing something a bit more impressive with the demo, and scaling it from a “$2 demo” to a “$30 demo”. The challenge was to create a visually appealing animation in high definition format and keep the demo time down to one hour.  This article will take a run through how I achieved this. Ray Tracing Ray tracing, a technique for generating high quality photorealistic images, gained popularity in the 90’s with companies like Pixar creating feature length computer animations, and also the emergence of shareware text-based ray tracers that could run on a home PC. In order to render a ray traced image, the ray of light that would pass from the view point must be tracked until it intersects with an object. At the intersection, the color, reflectiveness, transparency, and refractive index of the object are used to calculate if the ray will be reflected or refracted. Each pixel may require thousands of calculations to determine what color it will be in the rendered image. Pin-Board Toys Having very little artistic talent and a basic understanding of maths I decided to focus on an animation that could be modeled fairly easily and would look visually impressive. I’ve always liked the pin-board desktop toys that become popular in the 80’s and when I was working as a 3D animator back in the 90’s I always had the idea of creating a 3D ray-traced animation of a pin-board, but never found the energy to do it. Even if I had a go at it, the render time to produce an animation that would look respectable on a 486 would have been measured in months. PolyRay Back in 1995 I landed my first real job, after spending three years being a beach-ski-climbing-paragliding-bum, and was employed to create 3D ray-traced animations for a CD-ROM that school kids would use to learn physics. I had got into the strange and wonderful world of text-based ray tracing, and was using a shareware ray-tracer called PolyRay. PolyRay takes a text file describing a scene as input and, after a few hours processing on a 486, produced a high quality ray-traced image. The following is an example of a basic PolyRay scene file. background Midnight_Blue   static define matte surface { ambient 0.1 diffuse 0.7 } define matte_white texture { matte { color white } } define matte_black texture { matte { color dark_slate_gray } } define position_cylindrical 3 define lookup_sawtooth 1 define light_wood <0.6, 0.24, 0.1> define median_wood <0.3, 0.12, 0.03> define dark_wood <0.05, 0.01, 0.005>     define wooden texture { noise surface { ambient 0.2  diffuse 0.7  specular white, 0.5 microfacet Reitz 10 position_fn position_cylindrical position_scale 1  lookup_fn lookup_sawtooth octaves 1 turbulence 1 color_map( [0.0, 0.2, light_wood, light_wood] [0.2, 0.3, light_wood, median_wood] [0.3, 0.4, median_wood, light_wood] [0.4, 0.7, light_wood, light_wood] [0.7, 0.8, light_wood, median_wood] [0.8, 0.9, median_wood, light_wood] [0.9, 1.0, light_wood, dark_wood]) } } define glass texture { surface { ambient 0 diffuse 0 specular 0.2 reflection white, 0.1 transmission white, 1, 1.5 }} define shiny surface { ambient 0.1 diffuse 0.6 specular white, 0.6 microfacet Phong 7  } define steely_blue texture { shiny { color black } } define chrome texture { surface { color white ambient 0.0 diffuse 0.2 specular 0.4 microfacet Phong 10 reflection 0.8 } }   viewpoint {     from <4.000, -1.000, 1.000> at <0.000, 0.000, 0.000> up <0, 1, 0> angle 60     resolution 640, 480 aspect 1.6 image_format 0 }       light <-10, 30, 20> light <-10, 30, -20>   object { disc <0, -2, 0>, <0, 1, 0>, 30 wooden }   object { sphere <0.000, 0.000, 0.000>, 1.00 chrome } object { cylinder <0.000, 0.000, 0.000>, <0.000, 0.000, -4.000>, 0.50 chrome }   After setting up the background and defining colors and textures, the viewpoint is specified. The “camera” is located at a point in 3D space, and it looks towards another point. The angle, image resolution, and aspect ratio are specified. Two lights are present in the image at defined coordinates. The three objects in the image are a wooden disc to represent a table top, and a sphere and cylinder that intersect to form a pin that will be used for the pin board toy in the final animation. When the image is rendered, the following image is produced. The pins are modeled with a chrome surface, so they reflect the environment around them. Note that the scale of the pin shaft is not correct, this will be fixed later. Modeling the Pin Board The frame of the pin-board is made up of three boxes, and six cylinders, the front box is modeled using a clear, slightly reflective solid, with the same refractive index of glass. The other shapes are modeled as metal. object { box <-5.5, -1.5, 1>, <5.5, 5.5, 1.2> glass } object { box <-5.5, -1.5, -0.04>, <5.5, 5.5, -0.09> steely_blue } object { box <-5.5, -1.5, -0.52>, <5.5, 5.5, -0.59> steely_blue } object { cylinder <-5.2, -1.2, 1.4>, <-5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, -1.2, 1.4>, <5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <-5.2, 5.2, 1.4>, <-5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, 5.2, 1.4>, <5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <0, -1.2, 1.4>, <0, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <0, 5.2, 1.4>, <0, 5.2, -0.74>, 0.2 steely_blue }   In order to create the matrix of pins that make up the pin board I used a basic console application with a few nested loops to create two intersecting matrixes of pins, which models the layout used in the pin boards. The resulting image is shown below. The pin board contains 11,481 pins, with the scene file containing 23,709 lines of code. For the complete animation 2,000 scene files will be created, which is over 47 million lines of code. Each pin in the pin-board will slide out a specific distance when an object is pressed into the back of the board. This is easily modeled by setting the Z coordinate of the pin to a specific value. In order to set all of the pins in the pin-board to the correct position, a bitmap image can be used. The position of the pin can be set based on the color of the pixel at the appropriate position in the image. When the Windows Azure logo is used to set the Z coordinate of the pins, the following image is generated. The challenge now was to make a cool animation. The Azure Logo is fine, but it is static. Using a normal video to animate the pins would not work; the colors in the video would not be the same as the depth of the objects from the camera. In order to simulate the pin board accurately a series of frames from a depth camera could be used. Windows Kinect The Kenect controllers for the X-Box 360 and Windows feature a depth camera. The Kinect SDK for Windows provides a programming interface for Kenect, providing easy access for .NET developers to the Kinect sensors. The Kinect Explorer provided with the Kinect SDK is a great starting point for exploring Kinect from a developers perspective. Both the X-Box 360 Kinect and the Windows Kinect will work with the Kinect SDK, the Windows Kinect is required for commercial applications, but the X-Box Kinect can be used for hobby projects. The Windows Kinect has the advantage of providing a mode to allow depth capture with objects closer to the camera, which makes for a more accurate depth image for setting the pin positions. Creating a Depth Field Animation The depth field animation used to set the positions of the pin in the pin board was created using a modified version of the Kinect Explorer sample application. In order to simulate the pin board accurately, a small section of the depth range from the depth sensor will be used. Any part of the object in front of the depth range will result in a white pixel; anything behind the depth range will be black. Within the depth range the pixels in the image will be set to RGB values from 0,0,0 to 255,255,255. A screen shot of the modified Kinect Explorer application is shown below. The Kinect Explorer sample application was modified to include slider controls that are used to set the depth range that forms the image from the depth stream. This allows the fine tuning of the depth image that is required for simulating the position of the pins in the pin board. The Kinect Explorer was also modified to record a series of images from the depth camera and save them as a sequence JPEG files that will be used to animate the pins in the animation the Start and Stop buttons are used to start and stop the image recording. En example of one of the depth images is shown below. Once a series of 2,000 depth images has been captured, the task of creating the animation can begin. Rendering a Test Frame In order to test the creation of frames and get an approximation of the time required to render each frame a test frame was rendered on-premise using PolyRay. The output of the rendering process is shown below. The test frame contained 23,629 primitive shapes, most of which are the spheres and cylinders that are used for the 11,800 or so pins in the pin board. The 1280x720 image contains 921,600 pixels, but as anti-aliasing was used the number of rays that were calculated was 4,235,777, with 3,478,754,073 object boundaries checked. The test frame of the pin board with the depth field image applied is shown below. The tracing time for the test frame was 4 minutes 27 seconds, which means rendering the2,000 frames in the animation would take over 148 hours, or a little over 6 days. Although this is much faster that an old 486, waiting almost a week to see the results of an animation would make it challenging for animators to create, view, and refine their animations. It would be much better if the animation could be rendered in less than one hour. Windows Azure Worker Roles The cost of creating an on-premise render farm to render animations increases in proportion to the number of servers. The table below shows the cost of servers for creating a render farm, assuming a cost of $500 per server. Number of Servers Cost 1 $500 16 $8,000 256 $128,000   As well as the cost of the servers, there would be additional costs for networking, racks etc. Hosting an environment of 256 servers on-premise would require a server room with cooling, and some pretty hefty power cabling. The Windows Azure compute services provide worker roles, which are ideal for performing processor intensive compute tasks. With the scalability available in Windows Azure a job that takes 256 hours to complete could be perfumed using different numbers of worker roles. The time and cost of using 1, 16 or 256 worker roles is shown below. Number of Worker Roles Render Time Cost 1 256 hours $30.72 16 16 hours $30.72 256 1 hour $30.72   Using worker roles in Windows Azure provides the same cost for the 256 hour job, irrespective of the number of worker roles used. Provided the compute task can be broken down into many small units, and the worker role compute power can be used effectively, it makes sense to scale the application so that the task is completed quickly, making the results available in a timely fashion. The task of rendering 2,000 frames in an animation is one that can easily be broken down into 2,000 individual pieces, which can be performed by a number of worker roles. Creating a Render Farm in Windows Azure The architecture of the render farm is shown in the following diagram. The render farm is a hybrid application with the following components: ·         On-Premise o   Windows Kinect – Used combined with the Kinect Explorer to create a stream of depth images. o   Animation Creator – This application uses the depth images from the Kinect sensor to create scene description files for PolyRay. These files are then uploaded to the jobs blob container, and job messages added to the jobs queue. o   Process Monitor – This application queries the role instance lifecycle table and displays statistics about the render farm environment and render process. o   Image Downloader – This application polls the image queue and downloads the rendered animation files once they are complete. ·         Windows Azure o   Azure Storage – Queues and blobs are used for the scene description files and completed frames. A table is used to store the statistics about the rendering environment.   The architecture of each worker role is shown below.   The worker role is configured to use local storage, which provides file storage on the worker role instance that can be use by the applications to render the image and transform the format of the image. The service definition for the worker role with the local storage configuration highlighted is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="CloudRay" >   <WorkerRole name="CloudRayWorkerRole" vmsize="Small">     <Imports>     </Imports>     <ConfigurationSettings>       <Setting name="DataConnectionString" />     </ConfigurationSettings>     <LocalResources>       <LocalStorage name="RayFolder" cleanOnRoleRecycle="true" />     </LocalResources>   </WorkerRole> </ServiceDefinition>     The two executable programs, PolyRay.exe and DTA.exe are included in the Azure project, with Copy Always set as the property. PolyRay will take the scene description file and render it to a Truevision TGA file. As the TGA format has not seen much use since the mid 90’s it is converted to a JPG image using Dave's Targa Animator, another shareware application from the 90’s. Each worker roll will use the following process to render the animation frames. 1.       The worker process polls the job queue, if a job is available the scene description file is downloaded from blob storage to local storage. 2.       PolyRay.exe is started in a process with the appropriate command line arguments to render the image as a TGA file. 3.       DTA.exe is started in a process with the appropriate command line arguments convert the TGA file to a JPG file. 4.       The JPG file is uploaded from local storage to the images blob container. 5.       A message is placed on the images queue to indicate a new image is available for download. 6.       The job message is deleted from the job queue. 7.       The role instance lifecycle table is updated with statistics on the number of frames rendered by the worker role instance, and the CPU time used. The code for this is shown below. public override void Run() {     // Set environment variables     string polyRayPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), PolyRayLocation);     string dtaPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), DTALocation);       LocalResource rayStorage = RoleEnvironment.GetLocalResource("RayFolder");     string localStorageRootPath = rayStorage.RootPath;       JobQueue jobQueue = new JobQueue("renderjobs");     JobQueue downloadQueue = new JobQueue("renderimagedownloadjobs");     CloudRayBlob sceneBlob = new CloudRayBlob("scenes");     CloudRayBlob imageBlob = new CloudRayBlob("images");     RoleLifecycleDataSource roleLifecycleDataSource = new RoleLifecycleDataSource();       Frames = 0;       while (true)     {         // Get the render job from the queue         CloudQueueMessage jobMsg = jobQueue.Get();           if (jobMsg != null)         {             // Get the file details             string sceneFile = jobMsg.AsString;             string tgaFile = sceneFile.Replace(".pi", ".tga");             string jpgFile = sceneFile.Replace(".pi", ".jpg");               string sceneFilePath = Path.Combine(localStorageRootPath, sceneFile);             string tgaFilePath = Path.Combine(localStorageRootPath, tgaFile);             string jpgFilePath = Path.Combine(localStorageRootPath, jpgFile);               // Copy the scene file to local storage             sceneBlob.DownloadFile(sceneFilePath);               // Run the ray tracer.             string polyrayArguments =                 string.Format("\"{0}\" -o \"{1}\" -a 2", sceneFilePath, tgaFilePath);             Process polyRayProcess = new Process();             polyRayProcess.StartInfo.FileName =                 Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), polyRayPath);             polyRayProcess.StartInfo.Arguments = polyrayArguments;             polyRayProcess.Start();             polyRayProcess.WaitForExit();               // Convert the image             string dtaArguments =                 string.Format(" {0} /FJ /P{1}", tgaFilePath, Path.GetDirectoryName (jpgFilePath));             Process dtaProcess = new Process();             dtaProcess.StartInfo.FileName =                 Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), dtaPath);             dtaProcess.StartInfo.Arguments = dtaArguments;             dtaProcess.Start();             dtaProcess.WaitForExit();               // Upload the image to blob storage             imageBlob.UploadFile(jpgFilePath);               // Add a download job.             downloadQueue.Add(jpgFile);               // Delete the render job message             jobQueue.Delete(jobMsg);               Frames++;         }         else         {             Thread.Sleep(1000);         }           // Log the worker role activity.         roleLifecycleDataSource.Alive             ("CloudRayWorker", RoleLifecycleDataSource.RoleLifecycleId, Frames);     } }     Monitoring Worker Role Instance Lifecycle In order to get more accurate statistics about the lifecycle of the worker role instances used to render the animation data was tracked in an Azure storage table. The following class was used to track the worker role lifecycles in Azure storage.   public class RoleLifecycle : TableServiceEntity {     public string ServerName { get; set; }     public string Status { get; set; }     public DateTime StartTime { get; set; }     public DateTime EndTime { get; set; }     public long SecondsRunning { get; set; }     public DateTime LastActiveTime { get; set; }     public int Frames { get; set; }     public string Comment { get; set; }       public RoleLifecycle()     {     }       public RoleLifecycle(string roleName)     {         PartitionKey = roleName;         RowKey = Utils.GetAscendingRowKey();         Status = "Started";         StartTime = DateTime.UtcNow;         LastActiveTime = StartTime;         EndTime = StartTime;         SecondsRunning = 0;         Frames = 0;     } }     A new instance of this class is created and added to the storage table when the role starts. It is then updated each time the worker renders a frame to record the total number of frames rendered and the total processing time. These statistics are used be the monitoring application to determine the effectiveness of use of resources in the render farm. Rendering the Animation The Azure solution was deployed to Windows Azure with the service configuration set to 16 worker role instances. This allows for the application to be tested in the cloud environment, and the performance of the application determined. When I demo the application at conferences and user groups I often start with 16 instances, and then scale up the application to the full 256 instances. The configuration to run 16 instances is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*">   <Role name="CloudRayWorkerRole">     <Instances count="16" />     <ConfigurationSettings>       <Setting name="DataConnectionString"         value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." />     </ConfigurationSettings>   </Role> </ServiceConfiguration>     About six minutes after deploying the application the first worker roles become active and start to render the first frames of the animation. The CloudRay Monitor application displays an icon for each worker role instance, with a number indicating the number of frames that the worker role has rendered. The statistics on the left show the number of active worker roles and statistics about the render process. The render time is the time since the first worker role became active; the CPU time is the total amount of processing time used by all worker role instances to render the frames.   Five minutes after the first worker role became active the last of the 16 worker roles activated. By this time the first seven worker roles had each rendered one frame of the animation.   With 16 worker roles u and running it can be seen that one hour and 45 minutes CPU time has been used to render 32 frames with a render time of just under 10 minutes.     At this rate it would take over 10 hours to render the 2,000 frames of the full animation. In order to complete the animation in under an hour more processing power will be required. Scaling the render farm from 16 instances to 256 instances is easy using the new management portal. The slider is set to 256 instances, and the configuration saved. We do not need to re-deploy the application, and the 16 instances that are up and running will not be affected. Alternatively, the configuration file for the Azure service could be modified to specify 256 instances.   <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*">   <Role name="CloudRayWorkerRole">     <Instances count="256" />     <ConfigurationSettings>       <Setting name="DataConnectionString"         value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." />     </ConfigurationSettings>   </Role> </ServiceConfiguration>     Six minutes after the new configuration has been applied 75 new worker roles have activated and are processing their first frames.   Five minutes later the full configuration of 256 worker roles is up and running. We can see that the average rate of frame rendering has increased from 3 to 12 frames per minute, and that over 17 hours of CPU time has been utilized in 23 minutes. In this test the time to provision 140 worker roles was about 11 minutes, which works out at about one every five seconds.   We are now half way through the rendering, with 1,000 frames complete. This has utilized just under three days of CPU time in a little over 35 minutes.   The animation is now complete, with 2,000 frames rendered in a little over 52 minutes. The CPU time used by the 256 worker roles is 6 days, 7 hours and 22 minutes with an average frame rate of 38 frames per minute. The rendering of the last 1,000 frames took 16 minutes 27 seconds, which works out at a rendering rate of 60 frames per minute. The frame counts in the server instances indicate that the use of a queue to distribute the workload has been very effective in distributing the load across the 256 worker role instances. The first 16 instances that were deployed first have rendered between 11 and 13 frames each, whilst the 240 instances that were added when the application was scaled have rendered between 6 and 9 frames each.   Completed Animation I’ve uploaded the completed animation to YouTube, a low resolution preview is shown below. Pin Board Animation Created using Windows Kinect and 256 Windows Azure Worker Roles   The animation can be viewed in 1280x720 resolution at the following link: http://www.youtube.com/watch?v=n5jy6bvSxWc Effective Use of Resources According to the CloudRay monitor statistics the animation took 6 days, 7 hours and 22 minutes CPU to render, this works out at 152 hours of compute time, rounded up to the nearest hour. As the usage for the worker role instances are billed for the full hour, it may have been possible to render the animation using fewer than 256 worker roles. When deciding the optimal usage of resources, the time required to provision and start the worker roles must also be considered. In the demo I started with 16 worker roles, and then scaled the application to 256 worker roles. It would have been more optimal to start the application with maybe 200 worker roles, and utilized the full hour that I was being billed for. This would, however, have prevented showing the ease of scalability of the application. The new management portal displays the CPU usage across the worker roles in the deployment. The average CPU usage across all instances is 93.27%, with over 99% used when all the instances are up and running. This shows that the worker role resources are being used very effectively. Grid Computing Scenarios Although I am using this scenario for a hobby project, there are many scenarios where a large amount of compute power is required for a short period of time. Windows Azure provides a great platform for developing these types of grid computing applications, and can work out very cost effective. ·         Windows Azure can provide massive compute power, on demand, in a matter of minutes. ·         The use of queues to manage the load balancing of jobs between role instances is a simple and effective solution. ·         Using a cloud-computing platform like Windows Azure allows proof-of-concept scenarios to be tested and evaluated on a very low budget. ·         No charges for inbound data transfer makes the uploading of large data sets to Windows Azure Storage services cost effective. (Transaction charges still apply.) Tips for using Windows Azure for Grid Computing Scenarios I found the implementation of a render farm using Windows Azure a fairly simple scenario to implement. I was impressed by ease of scalability that Azure provides, and by the short time that the application took to scale from 16 to 256 worker role instances. In this case it was around 13 minutes, in other tests it took between 10 and 20 minutes. The following tips may be useful when implementing a grid computing project in Windows Azure. ·         Using an Azure Storage queue to load-balance the units of work across multiple worker roles is simple and very effective. The design I have used in this scenario could easily scale to many thousands of worker role instances. ·         Windows Azure accounts are typically limited to 20 cores. If you need to use more than this, a call to support and a credit card check will be required. ·         Be aware of how the billing model works. You will be charged for worker role instances for the full clock our in which the instance is deployed. Schedule the workload to start just after the clock hour has started. ·         Monitor the utilization of the resources you are provisioning, ensure that you are not paying for worker roles that are idle. ·         If you are deploying third party applications to worker roles, you may well run into licensing issues. Purchasing software licenses on a per-processor basis when using hundreds of processors for a short time period would not be cost effective. ·         Third party software may also require installation onto the worker roles, which can be accomplished using start-up tasks. Bear in mind that adding a startup task and possible re-boot will add to the time required for the worker role instance to start and activate. An alternative may be to use a prepared VM and use VM roles. ·         Consider using the Windows Azure Autoscaling Application Block (WASABi) to autoscale the worker roles in your application. When using a large number of worker roles, the utilization must be carefully monitored, if the scaling algorithms are not optimal it could get very expensive!

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  • Help getting frame rate (fps) up in Python + Pygame

    - by Jordan Magnuson
    I am working on a little card-swapping world-travel game that I sort of envision as a cross between Bejeweled and the 10 Days geography board games. So far the coding has been going okay, but the frame rate is pretty bad... currently I'm getting low 20's on my Core 2 Duo. This is a problem since I'm creating the game for Intel's March developer competition, which is squarely aimed at netbooks packing underpowered Atom processors. Here's a screen from the game: ![www.necessarygames.com/my_games/betraveled/betraveled-fps.png][1] I am very new to Python and Pygame (this is the first thing I've used them for), and am sadly lacking in formal CS training... which is to say that I think there are probably A LOT of bad practices going on in my code, and A LOT that could be optimized. If some of you older Python hands wouldn't mind taking a look at my code and seeing if you can't find any obvious areas for optimization, I would be extremely grateful. You can download the full source code here: http://www.necessarygames.com/my_games/betraveled/betraveled_src0328.zip Compiled exe here: www.necessarygames.com/my_games/betraveled/betraveled_src0328.zip One thing I am concerned about is my event manager, which I feel may have some performance wholes in it, and another thing is my rendering... I'm pretty much just blitting everything to the screen all the time (see the render routines in my game_components.py below); I recently found out that you should only update the areas of the screen that have changed, but I'm still foggy on how that accomplished exactly... could this be a huge performance issue? Any thoughts are much appreciated! As usual, I'm happy to "tip" you for your time and energy via PayPal. Jordan Here are some bits of the source: Main.py #Remote imports import pygame from pygame.locals import * #Local imports import config import rooms from event_manager import * from events import * class RoomController(object): """Controls which room is currently active (eg Title Screen)""" def __init__(self, screen, ev_manager): self.room = None self.screen = screen self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.room = self.set_room(config.room) def set_room(self, room_const): #Unregister old room from ev_manager if self.room: self.room.ev_manager.unregister_listener(self.room) self.room = None #Set new room based on const if room_const == config.TITLE_SCREEN: return rooms.TitleScreen(self.screen, self.ev_manager) elif room_const == config.GAME_MODE_ROOM: return rooms.GameModeRoom(self.screen, self.ev_manager) elif room_const == config.GAME_ROOM: return rooms.GameRoom(self.screen, self.ev_manager) elif room_const == config.HIGH_SCORES_ROOM: return rooms.HighScoresRoom(self.screen, self.ev_manager) def notify(self, event): if isinstance(event, ChangeRoomRequest): if event.game_mode: config.game_mode = event.game_mode self.room = self.set_room(event.new_room) def render(self, surface): self.room.render(surface) #Run game def main(): pygame.init() screen = pygame.display.set_mode(config.screen_size) ev_manager = EventManager() spinner = CPUSpinnerController(ev_manager) room_controller = RoomController(screen, ev_manager) pygame_event_controller = PyGameEventController(ev_manager) spinner.run() # this runs the main function if this script is called to run. # If it is imported as a module, we don't run the main function. if __name__ == "__main__": main() event_manager.py #Remote imports import pygame from pygame.locals import * #Local imports import config from events import * def debug( msg ): print "Debug Message: " + str(msg) class EventManager: #This object is responsible for coordinating most communication #between the Model, View, and Controller. def __init__(self): from weakref import WeakKeyDictionary self.listeners = WeakKeyDictionary() self.eventQueue= [] self.gui_app = None #---------------------------------------------------------------------- def register_listener(self, listener): self.listeners[listener] = 1 #---------------------------------------------------------------------- def unregister_listener(self, listener): if listener in self.listeners: del self.listeners[listener] #---------------------------------------------------------------------- def post(self, event): if isinstance(event, MouseButtonLeftEvent): debug(event.name) #NOTE: copying the list like this before iterating over it, EVERY tick, is highly inefficient, #but currently has to be done because of how new listeners are added to the queue while it is running #(eg when popping cards from a deck). Should be changed. See: http://dr0id.homepage.bluewin.ch/pygame_tutorial08.html #and search for "Watch the iteration" for listener in list(self.listeners): #NOTE: If the weakref has died, it will be #automatically removed, so we don't have #to worry about it. listener.notify(event) #------------------------------------------------------------------------------ class PyGameEventController: """...""" def __init__(self, ev_manager): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.input_freeze = False #---------------------------------------------------------------------- def notify(self, incoming_event): if isinstance(incoming_event, UserInputFreeze): self.input_freeze = True elif isinstance(incoming_event, UserInputUnFreeze): self.input_freeze = False elif isinstance(incoming_event, TickEvent): #Share some time with other processes, so we don't hog the cpu pygame.time.wait(5) #Handle Pygame Events for event in pygame.event.get(): #If this event manager has an associated PGU GUI app, notify it of the event if self.ev_manager.gui_app: self.ev_manager.gui_app.event(event) #Standard event handling for everything else ev = None if event.type == QUIT: ev = QuitEvent() elif event.type == pygame.MOUSEBUTTONDOWN and not self.input_freeze: if event.button == 1: #Button 1 pos = pygame.mouse.get_pos() ev = MouseButtonLeftEvent(pos) elif event.type == pygame.MOUSEMOTION: pos = pygame.mouse.get_pos() ev = MouseMoveEvent(pos) #Post event to event manager if ev: self.ev_manager.post(ev) #------------------------------------------------------------------------------ class CPUSpinnerController: def __init__(self, ev_manager): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.clock = pygame.time.Clock() self.cumu_time = 0 self.keep_going = True #---------------------------------------------------------------------- def run(self): if not self.keep_going: raise Exception('dead spinner') while self.keep_going: time_passed = self.clock.tick() fps = self.clock.get_fps() self.cumu_time += time_passed self.ev_manager.post(TickEvent(time_passed, fps)) if self.cumu_time >= 1000: self.cumu_time = 0 self.ev_manager.post(SecondEvent()) pygame.quit() #---------------------------------------------------------------------- def notify(self, event): if isinstance(event, QuitEvent): #this will stop the while loop from running self.keep_going = False rooms.py #Remote imports import pygame #Local imports import config import continents from game_components import * from my_gui import * from pgu import high class Room(object): def __init__(self, screen, ev_manager): self.screen = screen self.ev_manager = ev_manager self.ev_manager.register_listener(self) def notify(self, event): if isinstance(event, TickEvent): pygame.display.set_caption('FPS: ' + str(int(event.fps))) self.render(self.screen) pygame.display.update() def get_highs_table(self): fname = 'high_scores.txt' highs_table = None config.all_highs = high.Highs(fname) if config.game_mode == config.TIME_CHALLENGE: if config.difficulty == config.EASY: highs_table = config.all_highs['time_challenge_easy'] if config.difficulty == config.MED_DIF: highs_table = config.all_highs['time_challenge_med'] if config.difficulty == config.HARD: highs_table = config.all_highs['time_challenge_hard'] if config.difficulty == config.SUPER: highs_table = config.all_highs['time_challenge_super'] elif config.game_mode == config.PLAN_AHEAD: pass return highs_table class TitleScreen(Room): def __init__(self, screen, ev_manager): Room.__init__(self, screen, ev_manager) self.background = pygame.image.load('assets/images/interface/background.jpg').convert() #Initialize #--------------------------------------- self.gui_form = gui.Form() self.gui_app = gui.App(config.gui_theme) self.ev_manager.gui_app = self.gui_app c = gui.Container(align=0,valign=0) #Quit Button #--------------------------------------- b = StartGameButton(ev_manager=self.ev_manager) c.add(b, 0, 0) self.gui_app.init(c) def render(self, surface): surface.blit(self.background, (0, 0)) #GUI self.gui_app.paint(surface) class GameModeRoom(Room): def __init__(self, screen, ev_manager): Room.__init__(self, screen, ev_manager) self.background = pygame.image.load('assets/images/interface/background.jpg').convert() self.create_gui() #Create pgu gui elements def create_gui(self): #Setup #--------------------------------------- self.gui_form = gui.Form() self.gui_app = gui.App(config.gui_theme) self.ev_manager.gui_app = self.gui_app c = gui.Container(align=0,valign=-1) #Mode Relaxed Button #--------------------------------------- b = GameModeRelaxedButton(ev_manager=self.ev_manager) self.b = b print b.rect c.add(b, 0, 200) #Mode Time Challenge Button #--------------------------------------- b = TimeChallengeButton(ev_manager=self.ev_manager) self.b = b print b.rect c.add(b, 0, 250) #Mode Think Ahead Button #--------------------------------------- # b = PlanAheadButton(ev_manager=self.ev_manager) # self.b = b # print b.rect # c.add(b, 0, 300) #Initialize #--------------------------------------- self.gui_app.init(c) def render(self, surface): surface.blit(self.background, (0, 0)) #GUI self.gui_app.paint(surface) class GameRoom(Room): def __init__(self, screen, ev_manager): Room.__init__(self, screen, ev_manager) #Game mode #--------------------------------------- self.new_board_timer = None self.game_mode = config.game_mode config.current_highs = self.get_highs_table() self.highs_dialog = None self.game_over = False #Images #--------------------------------------- self.background = pygame.image.load('assets/images/interface/game screen2-1.jpg').convert() self.logo = pygame.image.load('assets/images/interface/logo_small.png').convert_alpha() self.game_over_text = pygame.image.load('assets/images/interface/text_game_over.png').convert_alpha() self.trip_complete_text = pygame.image.load('assets/images/interface/text_trip_complete.png').convert_alpha() self.zoom_game_over = None self.zoom_trip_complete = None self.fade_out = None #Text #--------------------------------------- self.font = pygame.font.Font(config.font_sans, config.interface_font_size) #Create game components #--------------------------------------- self.continent = self.set_continent(config.continent) self.board = Board(config.board_size, self.ev_manager) self.deck = Deck(self.ev_manager, self.continent) self.map = Map(self.continent) self.longest_trip = 0 #Set pos of game components #--------------------------------------- board_pos = (SCREEN_MARGIN[0], 109) self.board.set_pos(board_pos) map_pos = (config.screen_size[0] - self.map.size[0] - SCREEN_MARGIN[0], 57); self.map.set_pos(map_pos) #Trackers #--------------------------------------- self.game_clock = Chrono(self.ev_manager) self.swap_counter = 0 self.level = 0 #Create gui #--------------------------------------- self.create_gui() #Create initial board #--------------------------------------- self.new_board = self.deck.deal_new_board(self.board) self.ev_manager.post(NewBoardComplete(self.new_board)) def set_continent(self, continent_const): #Set continent based on const if continent_const == config.EUROPE: return continents.Europe() if continent_const == config.AFRICA: return continents.Africa() else: raise Exception('Continent constant not recognized') #Create pgu gui elements def create_gui(self): #Setup #--------------------------------------- self.gui_form = gui.Form() self.gui_app = gui.App(config.gui_theme) self.ev_manager.gui_app = self.gui_app c = gui.Container(align=-1,valign=-1) #Timer Progress bar #--------------------------------------- self.timer_bar = None self.time_increase = None self.minutes_left = None self.seconds_left = None self.timer_text = None if self.game_mode == config.TIME_CHALLENGE: self.time_increase = config.time_challenge_start_time self.timer_bar = gui.ProgressBar(config.time_challenge_start_time,0,config.max_time_bank,width=306) c.add(self.timer_bar, 172, 57) #Connections Progress bar #--------------------------------------- self.connections_bar = None self.connections_bar = gui.ProgressBar(0,0,config.longest_trip_needed,width=306) c.add(self.connections_bar, 172, 83) #Quit Button #--------------------------------------- b = QuitButton(ev_manager=self.ev_manager) c.add(b, 950, 20) #Generate Board Button #--------------------------------------- b = GenerateBoardButton(ev_manager=self.ev_manager, room=self) c.add(b, 500, 20) #Board Size? #--------------------------------------- bs = SetBoardSizeContainer(config.BOARD_LARGE, ev_manager=self.ev_manager, board=self.board) c.add(bs, 640, 20) #Fill Board? #--------------------------------------- t = FillBoardCheckbox(config.fill_board, ev_manager=self.ev_manager) c.add(t, 740, 20) #Darkness? #--------------------------------------- t = UseDarknessCheckbox(config.use_darkness, ev_manager=self.ev_manager) c.add(t, 840, 20) #Initialize #--------------------------------------- self.gui_app.init(c) def advance_level(self): self.level += 1 print 'Advancing to next level' print 'New level: ' + str(self.level) if self.timer_bar: print 'Time increase: ' + str(self.time_increase) self.timer_bar.value += self.time_increase self.time_increase = max(config.min_advance_time, int(self.time_increase * 0.9)) self.board = self.new_board self.new_board = None self.zoom_trip_complete = None self.game_clock.unpause() def notify(self, event): #Tick event if isinstance(event, TickEvent): pygame.display.set_caption('FPS: ' + str(int(event.fps))) self.render(self.screen) pygame.display.update() #Wait to deal new board when advancing levels if self.zoom_trip_complete and self.zoom_trip_complete.finished: self.zoom_trip_complete = None self.ev_manager.post(UnfreezeCards()) self.new_board = self.deck.deal_new_board(self.board) self.ev_manager.post(NewBoardComplete(self.new_board)) #New high score? if self.zoom_game_over and self.zoom_game_over.finished and not self.highs_dialog: if config.current_highs.check(self.level) != None: self.zoom_game_over.visible = False data = 'time:' + str(self.game_clock.time) + ',swaps:' + str(self.swap_counter) self.highs_dialog = HighScoreDialog(score=self.level, data=data, ev_manager=self.ev_manager) self.highs_dialog.open() elif not self.fade_out: self.fade_out = FadeOut(self.ev_manager, config.TITLE_SCREEN) #Second event elif isinstance(event, SecondEvent): if self.timer_bar: if not self.game_clock.paused: self.timer_bar.value -= 1 if self.timer_bar.value <= 0 and not self.game_over: self.ev_manager.post(GameOver()) self.minutes_left = self.timer_bar.value / 60 self.seconds_left = self.timer_bar.value % 60 if self.seconds_left < 10: leading_zero = '0' else: leading_zero = '' self.timer_text = ''.join(['Time Left: ', str(self.minutes_left), ':', leading_zero, str(self.seconds_left)]) #Game over elif isinstance(event, GameOver): self.game_over = True self.zoom_game_over = ZoomImage(self.ev_manager, self.game_over_text) #Trip complete event elif isinstance(event, TripComplete): print 'You did it!' self.game_clock.pause() self.zoom_trip_complete = ZoomImage(self.ev_manager, self.trip_complete_text) self.new_board_timer = Timer(self.ev_manager, 2) self.ev_manager.post(FreezeCards()) print 'Room posted newboardcomplete' #Board Refresh Complete elif isinstance(event, BoardRefreshComplete): if event.board == self.board: print 'Longest trip needed: ' + str(config.longest_trip_needed) print 'Your longest trip: ' + str(self.board.longest_trip) if self.board.longest_trip >= config.longest_trip_needed: self.ev_manager.post(TripComplete()) elif event.board == self.new_board: self.advance_level() self.connections_bar.value = self.board.longest_trip self.connection_text = ' '.join(['Connections:', str(self.board.longest_trip), '/', str(config.longest_trip_needed)]) #CardSwapComplete elif isinstance(event, CardSwapComplete): self.swap_counter += 1 elif isinstance(event, ConfigChangeBoardSize): config.board_size = event.new_size elif isinstance(event, ConfigChangeCardSize): config.card_size = event.new_size elif isinstance(event, ConfigChangeFillBoard): config.fill_board = event.new_value elif isinstance(event, ConfigChangeDarkness): config.use_darkness = event.new_value def render(self, surface): #Background surface.blit(self.background, (0, 0)) #Map self.map.render(surface) #Board self.board.render(surface) #Logo surface.blit(self.logo, (10,10)) #Text connection_text = self.font.render(self.connection_text, True, BLACK) surface.blit(connection_text, (25, 84)) if self.timer_text: timer_text = self.font.render(self.timer_text, True, BLACK) surface.blit(timer_text, (25, 64)) #GUI self.gui_app.paint(surface) if self.zoom_trip_complete: self.zoom_trip_complete.render(surface) if self.zoom_game_over: self.zoom_game_over.render(surface) if self.fade_out: self.fade_out.render(surface) class HighScoresRoom(Room): def __init__(self, screen, ev_manager): Room.__init__(self, screen, ev_manager) self.background = pygame.image.load('assets/images/interface/background.jpg').convert() #Initialize #--------------------------------------- self.gui_app = gui.App(config.gui_theme) self.ev_manager.gui_app = self.gui_app c = gui.Container(align=0,valign=0) #High Scores Table #--------------------------------------- hst = HighScoresTable() c.add(hst, 0, 0) self.gui_app.init(c) def render(self, surface): surface.blit(self.background, (0, 0)) #GUI self.gui_app.paint(surface) game_components.py #Remote imports import pygame from pygame.locals import * import random import operator from copy import copy from math import sqrt, floor #Local imports import config from events import * from matrix import Matrix from textrect import render_textrect, TextRectException from hyphen import hyphenator from textwrap2 import TextWrapper ############################## #CONSTANTS ############################## SCREEN_MARGIN = (10, 10) #Colors BLACK = (0, 0, 0) WHITE = (255, 255, 255) RED = (255, 0, 0) YELLOW = (255, 200, 0) #Directions LEFT = -1 RIGHT = 1 UP = 2 DOWN = -2 #Cards CARD_MARGIN = (10, 10) CARD_PADDING = (2, 2) #Card types BLANK = 0 COUNTRY = 1 TRANSPORT = 2 #Transport types PLANE = 0 TRAIN = 1 CAR = 2 SHIP = 3 class Timer(object): def __init__(self, ev_manager, time_left): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.time_left = time_left self.paused = False def __repr__(self): return str(self.time_left) def pause(self): self.paused = True def unpause(self): self.paused = False def notify(self, event): #Pause Event if isinstance(event, Pause): self.pause() #Unpause Event elif isinstance(event, Unpause): self.unpause() #Second Event elif isinstance(event, SecondEvent): if not self.paused: self.time_left -= 1 class Chrono(object): def __init__(self, ev_manager, start_time=0): self.ev_manager = ev_manager self.ev_manager.register_listener(self) self.time = start_time self.paused = False def __repr__(self): return str(self.time_left) def pause(self): self.paused = True def unpause(self): self.paused = False def notify(self, event): #Pause Event if isinstance(event, Pause): self.pause() #Unpause Event elif isinstance(event, Unpause): self.unpause() #Second Event elif isinstance(event, SecondEvent): if not self.paused: self.time += 1 class Map(object): def __init__(self, continent): self.map_image = pygame.image.load(continent.map).convert_alpha() self.map_text = pygame.image.load(continent.map_text).convert_alpha() self.pos = (0, 0) self.set_color() self.map_image = pygame.transform.smoothscale(self.map_image, config.map_size) self.size = self.map_image.get_size() def set_pos(self, pos): self.pos = pos def set_color(self): image_pixel_array = pygame.PixelArray(self.map_image) image_pixel_array.replace(config.GRAY1, config.COLOR1) image_pixel_array.replace(config.GRAY2, config.COLOR2) image_pixel_array.replace(config.GRAY3, config.COLOR3) image_pixel_array.replace(config.GRAY4, config.COLOR4) image_pixel_array.replace(config.GRAY5, config.COLOR5)

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  • Data Modeling: Logical Modeling Exercise

    - by swisscheese
    In trying to learn the art of data storage I have been trying to take in as much solid information as possible. PerformanceDBA posted some really helpful tutorials/examples in the following posts among others: is my data normalized? and Relational table naming convention. I already asked a subset question of this model here. So to make sure I understood the concepts he presented and I have seen elsewhere I wanted to take things a step or two further and see if I am grasping the concepts. Hence the purpose of this post, which hopefully others can also learn from. Everything I present is conceptual to me and for learning rather than applying it in some production system. It would be cool to get some input from PerformanceDBA also since I used his models to get started, but I appreciate all input given from anyone. As I am new to databases and especially modeling I will be the first to admit that I may not always ask the right questions, explain my thoughts clearly, or use the right verbage due to lack of expertise on the subject. So please keep that in mind and feel free to steer me in the right direction if I head off track. If there is enough interest in this I would like to take this from the logical to physical phases to show the evolution of the process and share it here on Stack. I will keep this thread for the Logical Diagram though and start new one for the additional steps. For my understanding I will be building a MySQL DB in the end to run some tests and see if what I came up with actually works. Here is the list of things that I want to capture in this conceptual model. Edit for V1.2 The purpose of this is to list Bands, their members, and the Events that they will be appearing at, as well as offer music and other merchandise for sale Members will be able to match up with friends Members can write reviews on the Bands, their music, and their events. There can only be one review per member on a given item, although they can edit their reviews and history will be maintained. BandMembers will have the chance to write a single Comment on Reviews about the Band they are associated with. Collectively as a Band only one Comment is allowed per Review. Members can then rate all Reviews and Comments but only once per given instance Members can select their favorite Bands, music, Merchandise, and Events Bands, Songs, and Events will be categorized into the type of Genre that they are and then further subcategorized into a SubGenre if necessary. It is ok for a Band or Event to fall into more then one Genre/SubGenre combination. Event date, time, and location will be posted for a given band and members can show that they will be attending the Event. An Event can be comprised of more than one Band, and multiple Events can take place at a single location on the same day Every party will be tied to at least one address and address history shall be maintained. Each party could also be tied to more then one address at a time (i.e. billing, shipping, physical) There will be stored profiles for Bands, BandMembers, and general members. So there it is, maybe a bit involved but could be a great learning tool for many hopefully as the process evolves and input is given by the community. Any input? EDIT v1.1 In response to PerformanceDBA U.3) That means no merchandise other than Band merchandise in the database. Correct ? That was my original thought but you got me thinking. Maybe the site would want to sell its own merchandise or even other merchandise from the bands. Not sure a mod to make for that. Would it require an entire rework of the Catalog section or just the identifying relationship that exists with the Band? Attempted a mod to sell both complete albums or song. Either way they would both be in electronic format only available for download. That is why I listed an Album as being comprised of Songs rather then 2 separate entities. U.5) I understand what you bring up about the circular relation with Favorite. I would like to get to this “It is either one Entity with some form of differentiation (FavoriteType) which identifies its treatment” but how to is not clear to me. What am I missing here? u.6) “Business Rules This is probably the only area you are weak in.” Thanks for the honest response. I will readdress these but I hope to clear up some confusion in my head first with the responses I have posted back to you. Q.1) Yes I would like to have Accepted, Rejected, and Blocked. I am not sure what you are referring to as to how this would change the logical model? Q.2) A person does not have to be a User. They can exist only as a BandMember. Is that what you are asking? Minor Issue Zero, One, or More…Oops I admit I forgot to give this attention when building the model. I am submitting this version as is and will address in a future version. I need to read up more on Constraint Checking to make sure I am understanding things. M.4) Depends if you envision OrderPurchase in the future. Can you expand as to what you mean here? EDIT V1.2 In response to PerformanceDBA input... Lessons learned. I was mixing the concept of Identifying / Non-Identifying and Cardinality (i.e. Genre / SubGenre), and doing so inconsistently to make things worse. Associative Tables are not required in Logical Diagrams as their many-to-many relationships can be depicted and then expanded in the Physical Model. I was overlooking the Cardinality in a lot of the relationships The importance of reading through relationships using effective Verb Phrases to reassure I am modeling what I want to accomplish. U.2) In the concept of this model it is only required to track a Venue as a location for an Event. No further data needs to be collected. With that being said Events will take place on a given EventDate and will be hosted at a Venue. Venues will host multiple events and possibly multiple events on a given date. In my new model my thinking was that EventDate is already tied to Event . Therefore, Venue will not need a relationship with EventDate. The 5th and 6th bullets you have listed under U.2) leave me questioning my thinking though. Am I missing something here? U.3) Is it time to move the link between Item and Band up to Item and Party instead? With the current design I don't see a possibility to sell merchandise not tied to the band as you have brought up. U.5) I left as per your input rather than making it a discrete Supertype/Subtype Relationship as I don’t see a benefit of having that type of roll up. Additional Revisions AR.1) After going through the exercise for FavoriteItem, I feel that Item to Review requires a many-to-many relationship so that is indicated. Necessary? Ok here we go for v1.3 I took a few days on this version, going back and forth with my design. Once the logical process is complete, as I want to see if I am on the right track, I will go through in depth what I had learned and the troubles I faced as a beginner going through this process. The big point for this version was it took throwing in some Keys to help see what I was missing in the past. Going through the process of doing a matrix proved to be of great help also. Regardless of anything, if it wasn't for the input given by PerformanceDBA I would still be a lost soul wondering in the dark. Who knows my current design might reaffirm that I still am, but I have learned a lot so I am know I at least have a flashlight in my hand. At this point in time I admit that I am still confused about identifying and non-identifying relationships. In my model I had to use non-identifying relationships with non nulls just to join the relationships I wanted to model. In reading a lot on the subject there seems to be a lot of disagreement and indecisiveness on the subject so I did what I thought represented the right things in my model. When to force (identifying) and when to be free (non-identifying)? Anyone have inputs? EDIT V1.4 Ok took the V1.3 inputs and cleaned things up for this V1.4 Currently working on a V1.5 to include attributes.

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  • Problem interfacing GSM USB modem to Java application

    - by varun
    I am working on an open-source application called FrontlineSMS which can be interfaced with GSM modems to send and receive SMS. The windows installer that is available through their website works fine. Since i wanted to modify it, I got the source code and built the jar and tried to launch it. When I plug in the GSM modem and launch the application, it sometimes detects the GSM device and i am even able to send and receive SMS. Or else 1.) I get the following error- Launching FrontlineSMS for Windows... Stable Library ========================================= Native lib Version = RXTX-2.1-7 Java lib Version = RXTX-2.1-7 Error 0x5 at /home/bob/foo/rxtx-devel/build/../src/termios.c(860): Access is de ied. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x5 at /home/bob/foo/rxtx-devel/build/../src/termios.c(860): Access is de ied. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x57 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2352): The parame er is incorrect. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. Error 0x1 at /home/bob/foo/rxtx-devel/build/../src/termios.c(2497): Incorrect f nction. 2.) OR the application sometimes crashes by creating a log file which contains: # # A fatal error has been detected by the Java Runtime Environment: # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x10009ccb, pid=4452, tid=3464 # # JRE version: 6.0_20-b02 # Java VM: Java HotSpot(TM) Client VM (16.3-b01 mixed mode, sharing windows-x86 ) # Problematic frame: # C [rxtxSerial.dll+0x9ccb] # # If you would like to submit a bug report, please visit: # http://java.sun.com/webapps/bugreport/crash.jsp # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # --------------- T H R E A D --------------- Current thread (0x03433000): JavaThread "SmsModem :: COM18" daemon [_thread_in_native, id=3464, stack(0x070a0000,0x070f0000)] siginfo: ExceptionCode=0xc0000005, writing address 0x038cfa10 Registers: EAX=0x038cfa08, EBX=0x00000003, ECX=0x7c802413, EDX=0x00000001 ESP=0x070ef800, EBP=0x070ef9e8, ESI=0x3360b898, EDI=0x03433000 EIP=0x10009ccb, EFLAGS=0x00010202 Top of Stack: (sp=0x070ef800) 0x070ef800: 3360b8a0 6d9fbc40 6da2ed98 ffffffff 0x070ef810: 070ef848 6d8f0a2c 6d8f0340 070ef95c 0x070ef820: 070ef864 00000dfb 03433000 038cfa08 0x070ef830: 00000007 00000001 00000001 0000000a 0x070ef840: 03433bf4 fffffffe 070ef8f4 6d8f0b7a 0x070ef850: 070ef95c 03433bf8 6da6f210 6da6f538 0x070ef860: 070ef868 03433bf4 27f18708 27f18708 0x070ef870: 22eb9810 03433bc4 00000001 070ef898 Instructions: (pc=0x10009ccb) 0x10009cbb: 45 1c 7c 19 8b 85 44 fe ff ff 8b 95 4c fe ff ff 0x10009ccb: 89 50 08 8b 55 f4 89 d0 e9 f8 01 00 00 c7 85 50 Stack: [0x070a0000,0x070f0000], sp=0x070ef800, free space=13e070ef334k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) C [rxtxSerial.dll+0x9ccb] C [rxtxSerial.dll+0xa05e] j gnu.io.RXTXPort.readByte()I+0 j gnu.io.RXTXPort$SerialInputStream.read()I+61 j org.smslib.CSerialDriver.getResponse()Ljava/lang/String;+36 j net.frontlinesms.smsdevice.SmsModem._doDetection()Z+172 j net.frontlinesms.smsdevice.SmsModem.run()V+18 v ~StubRoutines::call_stub V [jvm.dll+0xf049c] V [jvm.dll+0x17fcf1] V [jvm.dll+0xf0667] V [jvm.dll+0xf06dd] V [jvm.dll+0x11a2a0] V [jvm.dll+0x1ddb14] V [jvm.dll+0x17f96c] C [msvcr71.dll+0x9565] C [kernel32.dll+0xb729] Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j gnu.io.RXTXPort.readByte()I+0 j gnu.io.RXTXPort$SerialInputStream.read()I+61 j org.smslib.CSerialDriver.getResponse()Ljava/lang/String;+36 j net.frontlinesms.smsdevice.SmsModem._doDetection()Z+172 j net.frontlinesms.smsdevice.SmsModem.run()V+18 v ~StubRoutines::call_stub --------------- P R O C E S S --------------- Java Threads: ( => current thread ) =>0x03433000 JavaThread "SmsModem :: COM18" daemon [_thread_in_native, id=3464, stack(0x070a0000,0x070f0000)] 0x0344b800 JavaThread "D3D Screen Updater" daemon [_thread_blocked, id=4404, stack(0x03dd0000,0x03e20000)] 0x002b7800 JavaThread "DestroyJavaVM" [_thread_blocked, id=3236, stack(0x008c0000,0x00910000)] 0x03f6f400 JavaThread "AWT-EventQueue-0" [_thread_blocked, id=1888, stack(0x038e0000,0x03930000)] 0x03ec2400 JavaThread "AWT-Shutdown" [_thread_blocked, id=4300, stack(0x03740000,0x03790000)] 0x032d8c00 JavaThread "EmailServerHandler" [_thread_blocked, id=5708, stack(0x03830000,0x03880000)] 0x032f7000 JavaThread "Incoming message processor" [_thread_blocked, id=4184, stack(0x03650000,0x036a0000)] 0x03004c00 JavaThread "AWT-Windows" daemon [_thread_in_native, id=4828, stack(0x035a0000,0x035f0000)] 0x0303f400 JavaThread "Java2D Disposer" daemon [_thread_blocked, id=3768, stack(0x03500000,0x03550000)] 0x02b1e800 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=4164, stack(0x02dd0000,0x02e20000)] 0x02b18c00 JavaThread "CompilerThread0" daemon [_thread_blocked, id=2936, stack(0x02d80000,0x02dd0000)] 0x02b17400 JavaThread "Attach Listener" daemon [_thread_blocked, id=5444, stack(0x02d30000,0x02d80000)] 0x02b15c00 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=4976, stack(0x02ce0000,0x02d30000)] 0x02b0d800 JavaThread "Finalizer" daemon [_thread_blocked, id=5876, stack(0x02c90000,0x02ce0000)] 0x02b0c400 JavaThread "Reference Handler" daemon [_thread_blocked, id=5984, stack(0x02c40000,0x02c90000)] Other Threads: 0x02b0ac00 VMThread [stack: 0x02bf0000,0x02c40000] [id=4508] 0x02b29800 WatcherThread [stack: 0x02e20000,0x02e70000] [id=6080] VM state:not at safepoint (normal execution) VM Mutex/Monitor currently owned by a thread: None Heap def new generation total 7808K, used 4003K [0x22990000, 0x23200000, 0x27ee0000) eden space 6976K, 45% used [0x22990000, 0x22ca8e90, 0x23060000) from space 832K, 100% used [0x23060000, 0x23130000, 0x23130000) to space 832K, 0% used [0x23130000, 0x23130000, 0x23200000) tenured generation total 17208K, used 15192K [0x27ee0000, 0x28fae000, 0x32990000) the space 17208K, 88% used [0x27ee0000, 0x28db6100, 0x28db6200, 0x28fae000) compacting perm gen total 13824K, used 13655K [0x32990000, 0x33710000, 0x36990000) the space 13824K, 98% used [0x32990000, 0x336e5f98, 0x336e6000, 0x33710000) ro space 10240K, 51% used [0x36990000, 0x36ebae00, 0x36ebae00, 0x37390000) rw space 12288K, 54% used [0x37390000, 0x37a272d8, 0x37a27400, 0x37f90000) Dynamic libraries: 0x00400000 - 0x00424000 C:\WINDOWS\system32\java.exe 0x7c900000 - 0x7c9b2000 C:\WINDOWS\system32\ntdll.dll 0x7c800000 - 0x7c8f6000 C:\WINDOWS\system32\kernel32.dll 0x77dd0000 - 0x77e6b000 C:\WINDOWS\system32\ADVAPI32.dll 0x77e70000 - 0x77f02000 C:\WINDOWS\system32\RPCRT4.dll 0x77fe0000 - 0x77ff1000 C:\WINDOWS\system32\Secur32.dll 0x7c340000 - 0x7c396000 C:\Program Files\Java\jre6\bin\msvcr71.dll 0x6d800000 - 0x6da97000 C:\Program Files\Java\jre6\bin\client\jvm.dll 0x7e410000 - 0x7e4a1000 C:\WINDOWS\system32\USER32.dll 0x77f10000 - 0x77f59000 C:\WINDOWS\system32\GDI32.dll 0x76b40000 - 0x76b6d000 C:\WINDOWS\system32\WINMM.dll 0x76390000 - 0x763ad000 C:\WINDOWS\system32\IMM32.DLL 0x6d7b0000 - 0x6d7bc000 C:\Program Files\Java\jre6\bin\verify.dll 0x6d330000 - 0x6d34f000 C:\Program Files\Java\jre6\bin\java.dll 0x6d290000 - 0x6d298000 C:\Program Files\Java\jre6\bin\hpi.dll 0x76bf0000 - 0x76bfb000 C:\WINDOWS\system32\PSAPI.DLL 0x6d7f0000 - 0x6d7ff000 C:\Program Files\Java\jre6\bin\zip.dll 0x6d000000 - 0x6d14a000 C:\Program Files\Java\jre6\bin\awt.dll 0x73000000 - 0x73026000 C:\WINDOWS\system32\WINSPOOL.DRV 0x77c10000 - 0x77c68000 C:\WINDOWS\system32\msvcrt.dll 0x774e0000 - 0x7761d000 C:\WINDOWS\system32\ole32.dll 0x773d0000 - 0x774d3000 C:\WINDOWS\WinSxS\x86_Microsoft.Windows.Common-Controls_6595b64144ccf1df_6.0.2600.5512_x-ww_35d4ce83\COMCTL32.dll 0x77f60000 - 0x77fd6000 C:\WINDOWS\system32\SHLWAPI.dll 0x5ad70000 - 0x5ada8000 C:\WINDOWS\system32\uxtheme.dll 0x74720000 - 0x7476c000 C:\WINDOWS\system32\MSCTF.dll 0x755c0000 - 0x755ee000 C:\WINDOWS\system32\msctfime.ime 0x7c9c0000 - 0x7d1d7000 C:\WINDOWS\system32\shell32.dll 0x6d230000 - 0x6d284000 C:\Program Files\Java\jre6\bin\fontmanager.dll 0x68000000 - 0x68036000 C:\WINDOWS\system32\rsaenh.dll 0x769c0000 - 0x76a74000 C:\WINDOWS\system32\USERENV.dll 0x5b860000 - 0x5b8b5000 C:\WINDOWS\system32\netapi32.dll 0x6d610000 - 0x6d623000 C:\Program Files\Java\jre6\bin\net.dll 0x71ab0000 - 0x71ac7000 C:\WINDOWS\system32\WS2_32.dll 0x71aa0000 - 0x71aa8000 C:\WINDOWS\system32\WS2HELP.dll 0x71a50000 - 0x71a8f000 C:\WINDOWS\System32\mswsock.dll 0x76f20000 - 0x76f47000 C:\WINDOWS\system32\DNSAPI.dll 0x76fb0000 - 0x76fb8000 C:\WINDOWS\System32\winrnr.dll 0x76f60000 - 0x76f8c000 C:\WINDOWS\system32\WLDAP32.dll 0x16080000 - 0x160a5000 C:\Program Files\Bonjour\mdnsNSP.dll 0x76d60000 - 0x76d79000 C:\WINDOWS\system32\Iphlpapi.dll 0x63560000 - 0x63568000 C:\Program Files\National Instruments\Shared\mDNS Responder\nimdnsNSP.dll 0x63550000 - 0x63559000 C:\WINDOWS\system32\nimdnsResponder.dll 0x78130000 - 0x781cb000 C:\WINDOWS\WinSxS\x86_Microsoft.VC80.CRT_1fc8b3b9a1e18e3b_8.0.50727.4053_x-ww_e6967989\MSVCR80.dll 0x76fc0000 - 0x76fc6000 C:\WINDOWS\system32\rasadhlp.dll 0x10000000 - 0x10012000 C:\Documents and Settings\bjz677\Desktop\client run\rxtxSerial.dll 0x73d90000 - 0x73db7000 C:\WINDOWS\system32\crtdll.dll 0x4fdd0000 - 0x4ff76000 C:\WINDOWS\system32\d3d9.dll 0x038d0000 - 0x038d6000 C:\WINDOWS\system32\d3d8thk.dll 0x77c00000 - 0x77c08000 C:\WINDOWS\system32\VERSION.dll 0x6d630000 - 0x6d639000 C:\Program Files\Java\jre6\bin\nio.dll 0x03930000 - 0x03977000 C:\Program Files\Iomega\DriveIcons\IMGHOOK.DLL 0x605d0000 - 0x605d9000 C:\WINDOWS\system32\mslbui.dll 0x77120000 - 0x771ab000 C:\WINDOWS\system32\OLEAUT32.DLL VM Arguments: java_command: net.frontlinesms.DesktopLauncher Launcher Type: SUN_STANDARD Environment Variables: JAVA_HOME=C:\Program Files\Java\jdk1.6.0_20\bin CLASSPATH=.;C:\Program Files\Java\jre6\lib\ext\QTJava.zip; PATH=C:\Program Files\Intel\MKL\10.0.2.019\ia32\bin;C:\Program Files\Intel\VTune\CGGlbCache;C:\Program Files\Intel\VTune\Analyzer\Bin;C:\Program Files\Intel\VTune\Shared\Bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;s:\datamart\bin;C:\Program Files\ATI Technologies\ATI.ACE\;C:\Program Files\IVI\bin;c:\Program Files\Microsoft SQL Server\90\Tools\binn\;C:\Program Files\MATLAB\R2007b\bin;C:\Program Files\MATLAB\R2007b\bin\win32;C:\VXIPNP\WinNT\Bin;C:\Program Files\Intel\Compiler\Fortran\10.1.021\\IA32\Lib;C:\Program Files\Intel\Compiler\Fortran\10.1.021\\EM64T\Lib;C:\VXIPNP\WinNT\Bin\;C:\WINDOWS\system32\WindowsPowerShell\v1.0;C:\WINDOWS\system32\WindowsPowerShell\v1.0;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\Java\jdk1.6.0_20\bin USERNAME=xxx OS=Windows_NT PROCESSOR_IDENTIFIER=x86 Family 6 Model 15 Stepping 2, GenuineIntel --------------- S Y S T E M --------------- OS: Windows XP Build 2600 Service Pack 3 CPU:total 2 (2 cores per cpu, 1 threads per core) family 6 model 15 stepping 2, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3 Memory: 4k page, physical 2094960k(1063364k free), swap 4032536k(3038408k free) vm_info: Java HotSpot(TM) Client VM (16.3-b01) for windows-x86 JRE (1.6.0_20-b02), built on Apr 12 2010 13:52:23 by "java_re" with MS VC++ 7.1 (VS2003) time: Wed Jun 16 11:53:40 2010 elapsed time: 45 seconds Anyone knows what caused this? Please answer keeping in mind I am new to Java. Thanks, Varun

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  • Suckerfish Menu Not Working. Nested UL not displaying block

    - by Brett
    I'm going out of my mind with this one. I'm trying to build a suckerfish css drop down menu. I have the first level working ok but I can't get the nested ul (under the Glossary tab) to display in block format and show my a background color. I've been at this for three days and I'm about to go crazy. If anyone can help I'd really appreciate it. You can see it here: www.brettlockhart.com/blast/ body { min-width:640px; margin:0px; padding:0px 40px 0px 40px; background-color:#eee; } /*Nav One styles*/ nav#navOne ul { width:100%; min-width:640px; height:25px; margin:0px auto; padding:0px; background-image:url(/blast/images/navOneBg.png); border-radius:0px 0px 8px 8px; text-align:right; float:right; } nav#navOne ul li { position:relative; display:inline; margin: 0px 0px 0px 10px auto; padding:3px 0px; border-left:1px #0b4c8f solid; line-height:23px; } nav#navOne ul li:last-child { margin-right:10px; } .arrowDown { margin: auto; font-family:Tahoma, Geneva, sans-serif; font-size:.7em; color:#FFF; padding: 0px 5px 0px 0px; } nav#navOne ul li a { margin: 0px auto; padding: 4px 10px 4px 15px; font-family:Tahoma, Geneva, sans-serif; font-size:.7em; color:#FFF; border-left:1px #5d9ee0 solid; text-decoration:none; line-height:23px; } /*Nav One rollover*/ nav#navOne ul li ul { display:none; background-image:none; } nav#navOne ul li:hover ul { display:block !important; } nav#navOne ul li:hover nav#navOne ul li ul li { background-color:#69C !important; left:0px; top:26px; z-index:10; } h1 { float:left; width:158px; text-indent:-9999px; background-image:url(/blast/images/logo.png); background-repeat:no-repeat; } #search { float:right; width:280px; margin:0px; padding:0px; } /*Nav Two styles*/ nav#navTwo h3 { display:inline; } nav#navTwo ul { width:100%; height:50px; margin:0 auto; padding:0px; border:1px solid red; clear:both; } nav#navTwo ul li { display:inline; border: 1px solid green; margin-top:20px; } <header> <nav id="navOne"> <ul> <li><a href="#">Sign In</a></li> <li><a href="#">Register</a></li> <li><a href="#">Print Page</a></li> <li id="glossary"><a href="#">Glossary</a> <ul> <li><a href="#">Item Placeholder</a></li> <li><a href="#">Item Placeholder</a></li> <li><a href="#">Item Placeholder</a></li> <li><a href="#">Item Placeholder</a></li> <li><a href="#">Item Placeholder</a></li> <li><a href="#">Item Placeholder</a></li> </ul> </li> <li><a href="#">Text Size: A A A</a></li> <li><a href="#">Select Your Location</a> <span class="arrowDown">&#x2C5;</span></li> </ul> </nav><!--/navOne--> <h1>Logo</h1> <div id="search"> <form action="?" method="get"> <fieldset> <input type="text" id="searchField"> <input type="submit" id="searchSubmit" value="Submit"> Search:<label for="radioHere">here</label> <input type="radio" id="radioHere" name="here" value="here"> <label for="radioWeb">the web</label> <input type="radio" id="radioWeb" name="the web" value="the web"> </fieldset> </form> </div><!--/search--> <nav id="navTwo"> <ul> <li><h3>Residential:</h3></li> <li>TV</li> <li>Internet</li> <li>Phone</li> <li>Pricing</li> <li class="navTwoSelected">Music</li> <li>Order</li> <li>Billing</li> <li>Support</li> <li>|</li> <li>Business</li> <li>About Us</li> </ul> </nav><!--/navTwo--> <nav id="navThree"> <ul> <li>Today</li> <li>Watch</li> <li>Surf</li> <li>Play</li> <li class="navThreeSelected">Listen</li> <li>Learn</li> <li>Local</li> </ul> <h3>Tools:</h3> <ul> <li>Webmail</li> <li>Account</li> <li>Billing</li> <li>Order Services</li> </ul> </nav><!--/navThree--> <nav id="navFour"> <h3>Your are here:</h3> <ul id="breadcrumbs"> <li>Residential ></li> <li>My Place ></li> <li>Listen ></li> <li class="currentPage">Music</li> </ul> </nav><!--/navFour--> </header>

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  • How to improve this piece of code

    - by user303518
    Can anyone help me on this. It may be very frustrating for you all. But I want you guys to take a moment to look at the code below and please tell me all the things that are wrong in the below piece of code. You can copy it into your visual studio to analyze this better. You don’t have to make this code compile. My task is to get the following things: Most obvious mistakes with this code All the things that are wrong/bad practices with the code below Modify/Write an optimized version of this code. Keep in mind, the code DOES NOT need to compile. Reduce the number of lines of code You should NEVER try to implement something like below: public List<ValidationErrorDto> ProcessEQuote(string eQuoteXml, long programUniversalID) { // Get Program Info. DataTable programs = GetAllPrograms(); DataRow[] programRows = programs.Select(string.Format("ProgramUniversalID = {0}", programUniversalID)); long programID = (long)programRows[0]["ProgramID"]; string programName = (string)programRows[0]["Description"]; // Get Config file values. string fromEmail = ConfigurationManager.AppSettings["eQuotesFromEmail"]; string technicalSupportPhone = ConfigurationManager.AppSettings["TechnicalSupportPhone"]; string fromEmailDisplayName = string.IsNullOrEmpty(ConfigurationManager.AppSettings["eQuotesFromDisplayName"]) ? null : string.Format(ConfigurationManager.AppSettings["eQuotesFromDisplayName"], programName); string itEmail = !string.IsNullOrEmpty(ConfigurationManager.AppSettings["ITEmail"]) ? ConfigurationManager.AppSettings["ITEmail"] : string.Empty; string itName = !string.IsNullOrEmpty(ConfigurationManager.AppSettings["ITName"]) ? ConfigurationManager.AppSettings["ITName"] : "IT"; try { List<ValidationErrorDto> allValidationErrors = new List<ValidationErrorDto>(); List<ValidationErrorDto> validationErrors = new List<ValidationErrorDto>(); if (validationErrors.Count == 0) { validationErrors.AddRange(ValidateEQuoteXmlAgainstSchema(eQuoteXml)); if (validationErrors.Count == 0) { XmlDocument eQuoteXmlDoc = new XmlDocument(); eQuoteXmlDoc.LoadXml(eQuoteXml); XmlElement rootElement = eQuoteXmlDoc.DocumentElement; XmlNodeList quotesList = rootElement.SelectNodes("Quote"); foreach (XmlNode node in quotesList) { // Each node should be a quote node but to be safe, check if (node.Name == "Quote") { string groupName = node.SelectSingleNode("Group/GroupName").InnerText; string groupCity = node.SelectSingleNode("Group/GroupCity").InnerText; string groupPostalCode = node.SelectSingleNode("Group/GroupZipCode").InnerText; string groupSicCode = node.SelectSingleNode("Group/GroupSIC").InnerText; string generalAgencyLicenseNumber = node.SelectSingleNode("Group/GALicenseNbr").InnerText; string brokerName = node.SelectSingleNode("Group/BrokerName").InnerText; string deliverToEmailAddress = node.SelectSingleNode("Group/ReturnEmailAddress").InnerText; string brokerEmail = node.SelectSingleNode("Group/BrokerEmail").InnerText; string groupEligibleEmployeeCountString = node.SelectSingleNode("Group/GroupNbrEmployees").InnerText; string quoteEffectiveDateString = node.SelectSingleNode("Group/QuoteEffectiveDate").InnerText; string salesRepName = node.SelectSingleNode("Group/SalesRepName").InnerText; string salesRepPhone = node.SelectSingleNode("Group/SalesRepPhone").InnerText; string salesRepEmail = node.SelectSingleNode("Group/SalesRepEmail").InnerText; string brokerLicenseNumber = node.SelectSingleNode("Group/BrokerLicenseNbr").InnerText; DateTime? quoteEffectiveDate = null; int eligibleEmployeeCount = int.Parse(groupEligibleEmployeeCountString); DateTime quoteEffectiveDateOut; if (!DateTime.TryParse(quoteEffectiveDateString, out quoteEffectiveDateOut)) validationErrors.Add(ValidationHelper.CreateValidationError((long)QuoteField.EffectiveDate, "Quote Effective Date", ValidationErrorDto.ValueOutOfRange, false, ValidationHelper.CreateValidationContext(Entity.QuoteDetail, "Quote"))); else quoteEffectiveDate = quoteEffectiveDateOut; Dictionary<string, string> replacementCodeValues = new Dictionary<string, string>(); if (string.IsNullOrEmpty(Resources.ParameterMessageKeys.ResourceManager.GetString("GroupName"))) throw new InvalidOperationException("GroupName key is not configured"); replacementCodeValues.Add(Resources.ParameterMessageKeys.GroupName, groupName); replacementCodeValues.Add(Resources.ParameterMessageKeys.ProgramName, programName); replacementCodeValues.Add(Resources.ParameterMessageKeys.SalesRepName, salesRepName); replacementCodeValues.Add(Resources.ParameterMessageKeys.SalesRepPhone, salesRepPhone); replacementCodeValues.Add(Resources.ParameterMessageKeys.SalesRepEmail, salesRepEmail); replacementCodeValues.Add(Resources.ParameterMessageKeys.TechnicalSupportPhone, technicalSupportPhone); replacementCodeValues.Add(Resources.ParameterMessageKeys.EligibleEmployeCount, eligibleEmployeeCount.ToString()); // Retrieve the CityID and StateID long? cityID = null; long? stateID = null; DataSet citiesAndStates = Addresses.GetCitiesAndStatesFromPostalCode(groupPostalCode); DataTable cities = citiesAndStates.Tables[0]; DataTable states = citiesAndStates.Tables[1]; DataRow[] cityRows = cities.Select(string.Format("Name = '{0}'", groupCity)); if (cityRows.Length > 0) { cityID = (long)cityRows[0]["CityID"]; DataRow[] stateRows = states.Select(string.Format("CityID = {0}", cityID)); if (stateRows.Length > 0) stateID = (long)stateRows[0]["StateID"]; } // If the StateID does not exist, then we cannot get the GeneralAgency, so set a validation error and do not contine. // Else, Continue and look for an General Agency. If a GA was found, look for or create a Broker. Then look for or create a Prospect Group // Then using the info, create a quote. if (!stateID.HasValue) validationErrors.Add(ValidationHelper.CreateValidationError((long)ProspectGroupField.State, "Prospect Group State", ValidationErrorDto.RequiredFieldMissing, false, ValidationHelper.CreateValidationContext(Entity.ProspectGroup, "Prospect Group"))); bool brokerValidationError = false; SalesRepDto salesRep = GetSalesRepByEmail(salesRepEmail, ref validationErrors); if (salesRep == null) { string exceptionMessage = "Sales Rep Not found in Opportunity System. Please make sure Sales Rep is present in the system by adding the sales rep in AWP SR Add Screen." + Environment.NewLine; exceptionMessage = exceptionMessage + " Sales Rep Name: " + salesRepName + Environment.NewLine; exceptionMessage = exceptionMessage + " Sales Rep Email: " + salesRepEmail + Environment.NewLine; exceptionMessage = exceptionMessage + " Module : E-Quote Service" + Environment.NewLine; throw new Exception(exceptionMessage); } if (validationErrors.Count == 0) { // Note that StateID and EffectiveDate should be valid at this point. If it weren't there would be validation errors. // Find General Agency long? generalAgencyID; validationErrors.AddRange(GetEQuoteGeneralAgency(generalAgencyLicenseNumber, stateID.Value, out generalAgencyID)); // If GA was found, check for Broker. if (validationErrors.Count == 0 && generalAgencyID.HasValue) { Dictionary<string, string> brokerNameParts = ContactHelper.GetNamePartsFromFullName(brokerName); long? brokerID; validationErrors.AddRange(CreateEQuoteBroker(brokerNameParts["FirstName"], brokerNameParts["LastName"], brokerEmail, brokerLicenseNumber, stateID.Value, generalAgencyID.Value, salesRep, programID, out brokerID)); // If Broker was found but had validation errors if (validationErrors.Count > 0) { DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteBrokerValidationFailureMessageEmail, replacementCodeValues); brokerValidationError = true; } // If Broker was found, check for Prospect Group if (validationErrors.Count == 0 && brokerID.HasValue) { long? prospectGroupID; validationErrors.AddRange(CreateEQuoteProspectGroup(groupName, cityID, stateID, groupPostalCode, groupSicCode, brokerID.Value, out prospectGroupID)); if (validationErrors.Count == 0 && prospectGroupID.HasValue) { if (validationErrors.Count == 0) { long? quoteID; validationErrors.AddRange(CreateEQuote(programID, prospectGroupID.Value, generalAgencyID.Value, quoteEffectiveDate.Value, eligibleEmployeeCount, deliverToEmailAddress, node.SelectNodes("Employees/Employee"), deliverToEmailAddress, out quoteID)); if (validationErrors.Count == 0 && quoteID.HasValue) { QuoteFromServiceDto quoteFromService = GetQuoteByQuoteID(quoteID.Value); // Generate Pre-Message replacementCodeValues.Add(Resources.ParameterMessageKeys.QuoteNumber, string.Format("{0}.{1}", quoteFromService.QuoteNumber, quoteFromService.QuoteVersion)); replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, brokerName); replacementCodeValues.Add(Resources.ParameterMessageKeys.LicenseNumbers, brokerLicenseNumber); DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, deliverToEmailAddress, DocumentType.EQuotePreMessageEmail, replacementCodeValues); bool quoteGenerated = false; try { quoteGenerated = GenerateAndDeliverInitialQuote(quoteID.Value); } catch (Exception exception) { TraceLogger.LogException(exception, LoggingCategory); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Name)) replacementCodeValues[Resources.ParameterMessageKeys.Name] = itName; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, itName); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Errors)) replacementCodeValues[Resources.ParameterMessageKeys.Errors] = string.Format("Errors:\r\n:{0}", exception); else replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Format("Errors:\r\n:{0}", exception)); DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); } if (!quoteGenerated) { // Generate System Failure Message if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Name)) replacementCodeValues[Resources.ParameterMessageKeys.Name] = brokerName; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, brokerName); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Errors)) replacementCodeValues[Resources.ParameterMessageKeys.Errors] = string.Empty; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Empty); DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); } } } } } } } //if (validationErrors.Count > 0) // Per spec, if Broker Validation returned an error we already sent an email, don't send another generic one if (validationErrors.Count > 0 && (!brokerValidationError)) { StringBuilder errorString = new StringBuilder(); foreach (ValidationErrorDto validationError in validationErrors) errorString = errorString.AppendLine(string.Format(" - {0}", ValidationHelper.GetValidationErrorReason(validationError, true))); replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, errorString.ToString()); if (replacementCodeValues.ContainsKey(Resources.ParameterMessageKeys.Name)) replacementCodeValues[Resources.ParameterMessageKeys.Name] = brokerName; else replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, brokerName); // HACK: If there is no effective date, then use Today's date. Do we care about the effecitve dat on validation message? if (quoteEffectiveDate.HasValue) DeliverEmailMessage(programID, quoteEffectiveDate.Value, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteValidationFailureMessageEmail, replacementCodeValues); else DeliverEmailMessage(programID, DateTime.Now, fromEmail, fromEmailDisplayName, itEmail, DocumentType.EQuoteValidationFailureMessageEmail, replacementCodeValues); } allValidationErrors.AddRange(validationErrors); validationErrors.Clear(); } } } else { // Use todays date as the effective date. Dictionary<string, string> replacementCodeValues = new Dictionary<string, string>(); StringBuilder errorString = new StringBuilder(); foreach (ValidationErrorDto validationError in validationErrors) errorString = errorString.AppendLine(string.Format(" - {0}", ValidationHelper.GetValidationErrorReason(validationError, true))); replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Format("The following validation errors occurred: \r\n{0}", errorString)); replacementCodeValues.Add(Resources.ParameterMessageKeys.ProgramName, programName); replacementCodeValues.Add(Resources.ParameterMessageKeys.GroupName, "Group"); replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, itName); DeliverEmailMessage(programID, DateTime.Now, fromEmail, null, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); allValidationErrors.AddRange(validationErrors); validationErrors.Clear(); } } return allValidationErrors; } catch (Exception exception) { TraceLogger.LogException(exception, LoggingCategory); // Use todays date as the effective date. Dictionary<string, string> replacementCodeValues = new Dictionary<string, string>(); replacementCodeValues.Add(Resources.ParameterMessageKeys.ProgramName, programName); replacementCodeValues.Add(Resources.ParameterMessageKeys.GroupName, "Group"); replacementCodeValues.Add(Resources.ParameterMessageKeys.Name, itName); replacementCodeValues.Add(Resources.ParameterMessageKeys.Errors, string.Format("Errors:\r\n:{0}", exception)); DeliverEmailMessage(programID, DateTime.Now, fromEmail, null, itEmail, DocumentType.EQuoteSystemFailureMessageEmail, replacementCodeValues); throw new FaultException(exception.ToString()); } }

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  • Zen and the Art of File and Folder Organization

    - by Mark Virtue
    Is your desk a paragon of neatness, or does it look like a paper-bomb has gone off? If you’ve been putting off getting organized because the task is too huge or daunting, or you don’t know where to start, we’ve got 40 tips to get you on the path to zen mastery of your filing system. For all those readers who would like to get their files and folders organized, or, if they’re already organized, better organized—we have compiled a complete guide to getting organized and staying organized, a comprehensive article that will hopefully cover every possible tip you could want. Signs that Your Computer is Poorly Organized If your computer is a mess, you’re probably already aware of it.  But just in case you’re not, here are some tell-tale signs: Your Desktop has over 40 icons on it “My Documents” contains over 300 files and 60 folders, including MP3s and digital photos You use the Windows’ built-in search facility whenever you need to find a file You can’t find programs in the out-of-control list of programs in your Start Menu You save all your Word documents in one folder, all your spreadsheets in a second folder, etc Any given file that you’re looking for may be in any one of four different sets of folders But before we start, here are some quick notes: We’re going to assume you know what files and folders are, and how to create, save, rename, copy and delete them The organization principles described in this article apply equally to all computer systems.  However, the screenshots here will reflect how things look on Windows (usually Windows 7).  We will also mention some useful features of Windows that can help you get organized. Everyone has their own favorite methodology of organizing and filing, and it’s all too easy to get into “My Way is Better than Your Way” arguments.  The reality is that there is no perfect way of getting things organized.  When I wrote this article, I tried to keep a generalist and objective viewpoint.  I consider myself to be unusually well organized (to the point of obsession, truth be told), and I’ve had 25 years experience in collecting and organizing files on computers.  So I’ve got a lot to say on the subject.  But the tips I have described here are only one way of doing it.  Hopefully some of these tips will work for you too, but please don’t read this as any sort of “right” way to do it. At the end of the article we’ll be asking you, the reader, for your own organization tips. Why Bother Organizing At All? For some, the answer to this question is self-evident. And yet, in this era of powerful desktop search software (the search capabilities built into the Windows Vista and Windows 7 Start Menus, and third-party programs like Google Desktop Search), the question does need to be asked, and answered. I have a friend who puts every file he ever creates, receives or downloads into his My Documents folder and doesn’t bother filing them into subfolders at all.  He relies on the search functionality built into his Windows operating system to help him find whatever he’s looking for.  And he always finds it.  He’s a Search Samurai.  For him, filing is a waste of valuable time that could be spent enjoying life! It’s tempting to follow suit.  On the face of it, why would anyone bother to take the time to organize their hard disk when such excellent search software is available?  Well, if all you ever want to do with the files you own is to locate and open them individually (for listening, editing, etc), then there’s no reason to ever bother doing one scrap of organization.  But consider these common tasks that are not achievable with desktop search software: Find files manually.  Often it’s not convenient, speedy or even possible to utilize your desktop search software to find what you want.  It doesn’t work 100% of the time, or you may not even have it installed.  Sometimes its just plain faster to go straight to the file you want, if you know it’s in a particular sub-folder, rather than trawling through hundreds of search results. Find groups of similar files (e.g. all your “work” files, all the photos of your Europe holiday in 2008, all your music videos, all the MP3s from Dark Side of the Moon, all your letters you wrote to your wife, all your tax returns).  Clever naming of the files will only get you so far.  Sometimes it’s the date the file was created that’s important, other times it’s the file format, and other times it’s the purpose of the file.  How do you name a collection of files so that they’re easy to isolate based on any of the above criteria?  Short answer, you can’t. Move files to a new computer.  It’s time to upgrade your computer.  How do you quickly grab all the files that are important to you?  Or you decide to have two computers now – one for home and one for work.  How do you quickly isolate only the work-related files to move them to the work computer? Synchronize files to other computers.  If you have more than one computer, and you need to mirror some of your files onto the other computer (e.g. your music collection), then you need a way to quickly determine which files are to be synced and which are not.  Surely you don’t want to synchronize everything? Choose which files to back up.  If your backup regime calls for multiple backups, or requires speedy backups, then you’ll need to be able to specify which files are to be backed up, and which are not.  This is not possible if they’re all in the same folder. Finally, if you’re simply someone who takes pleasure in being organized, tidy and ordered (me! me!), then you don’t even need a reason.  Being disorganized is simply unthinkable. Tips on Getting Organized Here we present our 40 best tips on how to get organized.  Or, if you’re already organized, to get better organized. Tip #1.  Choose Your Organization System Carefully The reason that most people are not organized is that it takes time.  And the first thing that takes time is deciding upon a system of organization.  This is always a matter of personal preference, and is not something that a geek on a website can tell you.  You should always choose your own system, based on how your own brain is organized (which makes the assumption that your brain is, in fact, organized). We can’t instruct you, but we can make suggestions: You may want to start off with a system based on the users of the computer.  i.e. “My Files”, “My Wife’s Files”, My Son’s Files”, etc.  Inside “My Files”, you might then break it down into “Personal” and “Business”.  You may then realize that there are overlaps.  For example, everyone may want to share access to the music library, or the photos from the school play.  So you may create another folder called “Family”, for the “common” files. You may decide that the highest-level breakdown of your files is based on the “source” of each file.  In other words, who created the files.  You could have “Files created by ME (business or personal)”, “Files created by people I know (family, friends, etc)”, and finally “Files created by the rest of the world (MP3 music files, downloaded or ripped movies or TV shows, software installation files, gorgeous desktop wallpaper images you’ve collected, etc).”  This system happens to be the one I use myself.  See below:  Mark is for files created by meVC is for files created by my company (Virtual Creations)Others is for files created by my friends and familyData is the rest of the worldAlso, Settings is where I store the configuration files and other program data files for my installed software (more on this in tip #34, below). Each folder will present its own particular set of requirements for further sub-organization.  For example, you may decide to organize your music collection into sub-folders based on the artist’s name, while your digital photos might get organized based on the date they were taken.  It can be different for every sub-folder! Another strategy would be based on “currentness”.  Files you have yet to open and look at live in one folder.  Ones that have been looked at but not yet filed live in another place.  Current, active projects live in yet another place.  All other files (your “archive”, if you like) would live in a fourth folder. (And of course, within that last folder you’d need to create a further sub-system based on one of the previous bullet points). Put some thought into this – changing it when it proves incomplete can be a big hassle!  Before you go to the trouble of implementing any system you come up with, examine a wide cross-section of the files you own and see if they will all be able to find a nice logical place to sit within your system. Tip #2.  When You Decide on Your System, Stick to It! There’s nothing more pointless than going to all the trouble of creating a system and filing all your files, and then whenever you create, receive or download a new file, you simply dump it onto your Desktop.  You need to be disciplined – forever!  Every new file you get, spend those extra few seconds to file it where it belongs!  Otherwise, in just a month or two, you’ll be worse off than before – half your files will be organized and half will be disorganized – and you won’t know which is which! Tip #3.  Choose the Root Folder of Your Structure Carefully Every data file (document, photo, music file, etc) that you create, own or is important to you, no matter where it came from, should be found within one single folder, and that one single folder should be located at the root of your C: drive (as a sub-folder of C:\).  In other words, do not base your folder structure in standard folders like “My Documents”.  If you do, then you’re leaving it up to the operating system engineers to decide what folder structure is best for you.  And every operating system has a different system!  In Windows 7 your files are found in C:\Users\YourName, whilst on Windows XP it was C:\Documents and Settings\YourName\My Documents.  In UNIX systems it’s often /home/YourName. These standard default folders tend to fill up with junk files and folders that are not at all important to you.  “My Documents” is the worst offender.  Every second piece of software you install, it seems, likes to create its own folder in the “My Documents” folder.  These folders usually don’t fit within your organizational structure, so don’t use them!  In fact, don’t even use the “My Documents” folder at all.  Allow it to fill up with junk, and then simply ignore it.  It sounds heretical, but: Don’t ever visit your “My Documents” folder!  Remove your icons/links to “My Documents” and replace them with links to the folders you created and you care about! Create your own file system from scratch!  Probably the best place to put it would be on your D: drive – if you have one.  This way, all your files live on one drive, while all the operating system and software component files live on the C: drive – simply and elegantly separated.  The benefits of that are profound.  Not only are there obvious organizational benefits (see tip #10, below), but when it comes to migrate your data to a new computer, you can (sometimes) simply unplug your D: drive and plug it in as the D: drive of your new computer (this implies that the D: drive is actually a separate physical disk, and not a partition on the same disk as C:).  You also get a slight speed improvement (again, only if your C: and D: drives are on separate physical disks). Warning:  From tip #12, below, you will see that it’s actually a good idea to have exactly the same file system structure – including the drive it’s filed on – on all of the computers you own.  So if you decide to use the D: drive as the storage system for your own files, make sure you are able to use the D: drive on all the computers you own.  If you can’t ensure that, then you can still use a clever geeky trick to store your files on the D: drive, but still access them all via the C: drive (see tip #17, below). If you only have one hard disk (C:), then create a dedicated folder that will contain all your files – something like C:\Files.  The name of the folder is not important, but make it a single, brief word. There are several reasons for this: When creating a backup regime, it’s easy to decide what files should be backed up – they’re all in the one folder! If you ever decide to trade in your computer for a new one, you know exactly which files to migrate You will always know where to begin a search for any file If you synchronize files with other computers, it makes your synchronization routines very simple.   It also causes all your shortcuts to continue to work on the other machines (more about this in tip #24, below). Once you’ve decided where your files should go, then put all your files in there – Everything!  Completely disregard the standard, default folders that are created for you by the operating system (“My Music”, “My Pictures”, etc).  In fact, you can actually relocate many of those folders into your own structure (more about that below, in tip #6). The more completely you get all your data files (documents, photos, music, etc) and all your configuration settings into that one folder, then the easier it will be to perform all of the above tasks. Once this has been done, and all your files live in one folder, all the other folders in C:\ can be thought of as “operating system” folders, and therefore of little day-to-day interest for us. Here’s a screenshot of a nicely organized C: drive, where all user files are located within the \Files folder:   Tip #4.  Use Sub-Folders This would be our simplest and most obvious tip.  It almost goes without saying.  Any organizational system you decide upon (see tip #1) will require that you create sub-folders for your files.  Get used to creating folders on a regular basis. Tip #5.  Don’t be Shy About Depth Create as many levels of sub-folders as you need.  Don’t be scared to do so.  Every time you notice an opportunity to group a set of related files into a sub-folder, do so.  Examples might include:  All the MP3s from one music CD, all the photos from one holiday, or all the documents from one client. It’s perfectly okay to put files into a folder called C:\Files\Me\From Others\Services\WestCo Bank\Statements\2009.  That’s only seven levels deep.  Ten levels is not uncommon.  Of course, it’s possible to take this too far.  If you notice yourself creating a sub-folder to hold only one file, then you’ve probably become a little over-zealous.  On the other hand, if you simply create a structure with only two levels (for example C:\Files\Work) then you really haven’t achieved any level of organization at all (unless you own only six files!).  Your “Work” folder will have become a dumping ground, just like your Desktop was, with most likely hundreds of files in it. Tip #6.  Move the Standard User Folders into Your Own Folder Structure Most operating systems, including Windows, create a set of standard folders for each of its users.  These folders then become the default location for files such as documents, music files, digital photos and downloaded Internet files.  In Windows 7, the full list is shown below: Some of these folders you may never use nor care about (for example, the Favorites folder, if you’re not using Internet Explorer as your browser).  Those ones you can leave where they are.  But you may be using some of the other folders to store files that are important to you.  Even if you’re not using them, Windows will still often treat them as the default storage location for many types of files.  When you go to save a standard file type, it can become annoying to be automatically prompted to save it in a folder that’s not part of your own file structure. But there’s a simple solution:  Move the folders you care about into your own folder structure!  If you do, then the next time you go to save a file of the corresponding type, Windows will prompt you to save it in the new, moved location. Moving the folders is easy.  Simply drag-and-drop them to the new location.  Here’s a screenshot of the default My Music folder being moved to my custom personal folder (Mark): Tip #7.  Name Files and Folders Intelligently This is another one that almost goes without saying, but we’ll say it anyway:  Do not allow files to be created that have meaningless names like Document1.doc, or folders called New Folder (2).  Take that extra 20 seconds and come up with a meaningful name for the file/folder – one that accurately divulges its contents without repeating the entire contents in the name. Tip #8.  Watch Out for Long Filenames Another way to tell if you have not yet created enough depth to your folder hierarchy is that your files often require really long names.  If you need to call a file Johnson Sales Figures March 2009.xls (which might happen to live in the same folder as Abercrombie Budget Report 2008.xls), then you might want to create some sub-folders so that the first file could be simply called March.xls, and living in the Clients\Johnson\Sales Figures\2009 folder. A well-placed file needs only a brief filename! Tip #9.  Use Shortcuts!  Everywhere! This is probably the single most useful and important tip we can offer.  A shortcut allows a file to be in two places at once. Why would you want that?  Well, the file and folder structure of every popular operating system on the market today is hierarchical.  This means that all objects (files and folders) always live within exactly one parent folder.  It’s a bit like a tree.  A tree has branches (folders) and leaves (files).  Each leaf, and each branch, is supported by exactly one parent branch, all the way back to the root of the tree (which, incidentally, is exactly why C:\ is called the “root folder” of the C: drive). That hard disks are structured this way may seem obvious and even necessary, but it’s only one way of organizing data.  There are others:  Relational databases, for example, organize structured data entirely differently.  The main limitation of hierarchical filing structures is that a file can only ever be in one branch of the tree – in only one folder – at a time.  Why is this a problem?  Well, there are two main reasons why this limitation is a problem for computer users: The “correct” place for a file, according to our organizational rationale, is very often a very inconvenient place for that file to be located.  Just because it’s correctly filed doesn’t mean it’s easy to get to.  Your file may be “correctly” buried six levels deep in your sub-folder structure, but you may need regular and speedy access to this file every day.  You could always move it to a more convenient location, but that would mean that you would need to re-file back to its “correct” location it every time you’d finished working on it.  Most unsatisfactory. A file may simply “belong” in two or more different locations within your file structure.  For example, say you’re an accountant and you have just completed the 2009 tax return for John Smith.  It might make sense to you to call this file 2009 Tax Return.doc and file it under Clients\John Smith.  But it may also be important to you to have the 2009 tax returns from all your clients together in the one place.  So you might also want to call the file John Smith.doc and file it under Tax Returns\2009.  The problem is, in a purely hierarchical filing system, you can’t put it in both places.  Grrrrr! Fortunately, Windows (and most other operating systems) offers a way for you to do exactly that:  It’s called a “shortcut” (also known as an “alias” on Macs and a “symbolic link” on UNIX systems).  Shortcuts allow a file to exist in one place, and an icon that represents the file to be created and put anywhere else you please.  In fact, you can create a dozen such icons and scatter them all over your hard disk.  Double-clicking on one of these icons/shortcuts opens up the original file, just as if you had double-clicked on the original file itself. Consider the following two icons: The one on the left is the actual Word document, while the one on the right is a shortcut that represents the Word document.  Double-clicking on either icon will open the same file.  There are two main visual differences between the icons: The shortcut will have a small arrow in the lower-left-hand corner (on Windows, anyway) The shortcut is allowed to have a name that does not include the file extension (the “.docx” part, in this case) You can delete the shortcut at any time without losing any actual data.  The original is still intact.  All you lose is the ability to get to that data from wherever the shortcut was. So why are shortcuts so great?  Because they allow us to easily overcome the main limitation of hierarchical file systems, and put a file in two (or more) places at the same time.  You will always have files that don’t play nice with your organizational rationale, and can’t be filed in only one place.  They demand to exist in two places.  Shortcuts allow this!  Furthermore, they allow you to collect your most often-opened files and folders together in one spot for convenient access.  The cool part is that the original files stay where they are, safe forever in their perfectly organized location. So your collection of most often-opened files can – and should – become a collection of shortcuts! If you’re still not convinced of the utility of shortcuts, consider the following well-known areas of a typical Windows computer: The Start Menu (and all the programs that live within it) The Quick Launch bar (or the Superbar in Windows 7) The “Favorite folders” area in the top-left corner of the Windows Explorer window (in Windows Vista or Windows 7) Your Internet Explorer Favorites or Firefox Bookmarks Each item in each of these areas is a shortcut!  Each of those areas exist for one purpose only:  For convenience – to provide you with a collection of the files and folders you access most often. It should be easy to see by now that shortcuts are designed for one single purpose:  To make accessing your files more convenient.  Each time you double-click on a shortcut, you are saved the hassle of locating the file (or folder, or program, or drive, or control panel icon) that it represents. Shortcuts allow us to invent a golden rule of file and folder organization: “Only ever have one copy of a file – never have two copies of the same file.  Use a shortcut instead” (this rule doesn’t apply to copies created for backup purposes, of course!) There are also lesser rules, like “don’t move a file into your work area – create a shortcut there instead”, and “any time you find yourself frustrated with how long it takes to locate a file, create a shortcut to it and place that shortcut in a convenient location.” So how to we create these massively useful shortcuts?  There are two main ways: “Copy” the original file or folder (click on it and type Ctrl-C, or right-click on it and select Copy):  Then right-click in an empty area of the destination folder (the place where you want the shortcut to go) and select Paste shortcut: Right-drag (drag with the right mouse button) the file from the source folder to the destination folder.  When you let go of the mouse button at the destination folder, a menu pops up: Select Create shortcuts here. Note that when shortcuts are created, they are often named something like Shortcut to Budget Detail.doc (windows XP) or Budget Detail – Shortcut.doc (Windows 7).   If you don’t like those extra words, you can easily rename the shortcuts after they’re created, or you can configure Windows to never insert the extra words in the first place (see our article on how to do this). And of course, you can create shortcuts to folders too, not just to files! Bottom line: Whenever you have a file that you’d like to access from somewhere else (whether it’s convenience you’re after, or because the file simply belongs in two places), create a shortcut to the original file in the new location. Tip #10.  Separate Application Files from Data Files Any digital organization guru will drum this rule into you.  Application files are the components of the software you’ve installed (e.g. Microsoft Word, Adobe Photoshop or Internet Explorer).  Data files are the files that you’ve created for yourself using that software (e.g. Word Documents, digital photos, emails or playlists). Software gets installed, uninstalled and upgraded all the time.  Hopefully you always have the original installation media (or downloaded set-up file) kept somewhere safe, and can thus reinstall your software at any time.  This means that the software component files are of little importance.  Whereas the files you have created with that software is, by definition, important.  It’s a good rule to always separate unimportant files from important files. So when your software prompts you to save a file you’ve just created, take a moment and check out where it’s suggesting that you save the file.  If it’s suggesting that you save the file into the same folder as the software itself, then definitely don’t follow that suggestion.  File it in your own folder!  In fact, see if you can find the program’s configuration option that determines where files are saved by default (if it has one), and change it. Tip #11.  Organize Files Based on Purpose, Not on File Type If you have, for example a folder called Work\Clients\Johnson, and within that folder you have two sub-folders, Word Documents and Spreadsheets (in other words, you’re separating “.doc” files from “.xls” files), then chances are that you’re not optimally organized.  It makes little sense to organize your files based on the program that created them.  Instead, create your sub-folders based on the purpose of the file.  For example, it would make more sense to create sub-folders called Correspondence and Financials.  It may well be that all the files in a given sub-folder are of the same file-type, but this should be more of a coincidence and less of a design feature of your organization system. Tip #12.  Maintain the Same Folder Structure on All Your Computers In other words, whatever organizational system you create, apply it to every computer that you can.  There are several benefits to this: There’s less to remember.  No matter where you are, you always know where to look for your files If you copy or synchronize files from one computer to another, then setting up the synchronization job becomes very simple Shortcuts can be copied or moved from one computer to another with ease (assuming the original files are also copied/moved).  There’s no need to find the target of the shortcut all over again on the second computer Ditto for linked files (e.g Word documents that link to data in a separate Excel file), playlists, and any files that reference the exact file locations of other files. This applies even to the drive that your files are stored on.  If your files are stored on C: on one computer, make sure they’re stored on C: on all your computers.  Otherwise all your shortcuts, playlists and linked files will stop working! Tip #13.  Create an “Inbox” Folder Create yourself a folder where you store all files that you’re currently working on, or that you haven’t gotten around to filing yet.  You can think of this folder as your “to-do” list.  You can call it “Inbox” (making it the same metaphor as your email system), or “Work”, or “To-Do”, or “Scratch”, or whatever name makes sense to you.  It doesn’t matter what you call it – just make sure you have one! Once you have finished working on a file, you then move it from the “Inbox” to its correct location within your organizational structure. You may want to use your Desktop as this “Inbox” folder.  Rightly or wrongly, most people do.  It’s not a bad place to put such files, but be careful:  If you do decide that your Desktop represents your “to-do” list, then make sure that no other files find their way there.  In other words, make sure that your “Inbox”, wherever it is, Desktop or otherwise, is kept free of junk – stray files that don’t belong there. So where should you put this folder, which, almost by definition, lives outside the structure of the rest of your filing system?  Well, first and foremost, it has to be somewhere handy.  This will be one of your most-visited folders, so convenience is key.  Putting it on the Desktop is a great option – especially if you don’t have any other folders on your Desktop:  the folder then becomes supremely easy to find in Windows Explorer: You would then create shortcuts to this folder in convenient spots all over your computer (“Favorite Links”, “Quick Launch”, etc). Tip #14.  Ensure You have Only One “Inbox” Folder Once you’ve created your “Inbox” folder, don’t use any other folder location as your “to-do list”.  Throw every incoming or created file into the Inbox folder as you create/receive it.  This keeps the rest of your computer pristine and free of randomly created or downloaded junk.  The last thing you want to be doing is checking multiple folders to see all your current tasks and projects.  Gather them all together into one folder. Here are some tips to help ensure you only have one Inbox: Set the default “save” location of all your programs to this folder. Set the default “download” location for your browser to this folder. If this folder is not your desktop (recommended) then also see if you can make a point of not putting “to-do” files on your desktop.  This keeps your desktop uncluttered and Zen-like: (the Inbox folder is in the bottom-right corner) Tip #15.  Be Vigilant about Clearing Your “Inbox” Folder This is one of the keys to staying organized.  If you let your “Inbox” overflow (i.e. allow there to be more than, say, 30 files or folders in there), then you’re probably going to start feeling like you’re overwhelmed:  You’re not keeping up with your to-do list.  Once your Inbox gets beyond a certain point (around 30 files, studies have shown), then you’ll simply start to avoid it.  You may continue to put files in there, but you’ll be scared to look at it, fearing the “out of control” feeling that all overworked, chaotic or just plain disorganized people regularly feel. So, here’s what you can do: Visit your Inbox/to-do folder regularly (at least five times per day). Scan the folder regularly for files that you have completed working on and are ready for filing.  File them immediately. Make it a source of pride to keep the number of files in this folder as small as possible.  If you value peace of mind, then make the emptiness of this folder one of your highest (computer) priorities If you know that a particular file has been in the folder for more than, say, six weeks, then admit that you’re not actually going to get around to processing it, and move it to its final resting place. Tip #16.  File Everything Immediately, and Use Shortcuts for Your Active Projects As soon as you create, receive or download a new file, store it away in its “correct” folder immediately.  Then, whenever you need to work on it (possibly straight away), create a shortcut to it in your “Inbox” (“to-do”) folder or your desktop.  That way, all your files are always in their “correct” locations, yet you still have immediate, convenient access to your current, active files.  When you finish working on a file, simply delete the shortcut. Ideally, your “Inbox” folder – and your Desktop – should contain no actual files or folders.  They should simply contain shortcuts. Tip #17.  Use Directory Symbolic Links (or Junctions) to Maintain One Unified Folder Structure Using this tip, we can get around a potential hiccup that we can run into when creating our organizational structure – the issue of having more than one drive on our computer (C:, D:, etc).  We might have files we need to store on the D: drive for space reasons, and yet want to base our organized folder structure on the C: drive (or vice-versa). Your chosen organizational structure may dictate that all your files must be accessed from the C: drive (for example, the root folder of all your files may be something like C:\Files).  And yet you may still have a D: drive and wish to take advantage of the hundreds of spare Gigabytes that it offers.  Did you know that it’s actually possible to store your files on the D: drive and yet access them as if they were on the C: drive?  And no, we’re not talking about shortcuts here (although the concept is very similar). By using the shell command mklink, you can essentially take a folder that lives on one drive and create an alias for it on a different drive (you can do lots more than that with mklink – for a full rundown on this programs capabilities, see our dedicated article).  These aliases are called directory symbolic links (and used to be known as junctions).  You can think of them as “virtual” folders.  They function exactly like regular folders, except they’re physically located somewhere else. For example, you may decide that your entire D: drive contains your complete organizational file structure, but that you need to reference all those files as if they were on the C: drive, under C:\Files.  If that was the case you could create C:\Files as a directory symbolic link – a link to D:, as follows: mklink /d c:\files d:\ Or it may be that the only files you wish to store on the D: drive are your movie collection.  You could locate all your movie files in the root of your D: drive, and then link it to C:\Files\Media\Movies, as follows: mklink /d c:\files\media\movies d:\ (Needless to say, you must run these commands from a command prompt – click the Start button, type cmd and press Enter) Tip #18. Customize Your Folder Icons This is not strictly speaking an organizational tip, but having unique icons for each folder does allow you to more quickly visually identify which folder is which, and thus saves you time when you’re finding files.  An example is below (from my folder that contains all files downloaded from the Internet): To learn how to change your folder icons, please refer to our dedicated article on the subject. Tip #19.  Tidy Your Start Menu The Windows Start Menu is usually one of the messiest parts of any Windows computer.  Every program you install seems to adopt a completely different approach to placing icons in this menu.  Some simply put a single program icon.  Others create a folder based on the name of the software.  And others create a folder based on the name of the software manufacturer.  It’s chaos, and can make it hard to find the software you want to run. Thankfully we can avoid this chaos with useful operating system features like Quick Launch, the Superbar or pinned start menu items. Even so, it would make a lot of sense to get into the guts of the Start Menu itself and give it a good once-over.  All you really need to decide is how you’re going to organize your applications.  A structure based on the purpose of the application is an obvious candidate.  Below is an example of one such structure: In this structure, Utilities means software whose job it is to keep the computer itself running smoothly (configuration tools, backup software, Zip programs, etc).  Applications refers to any productivity software that doesn’t fit under the headings Multimedia, Graphics, Internet, etc. In case you’re not aware, every icon in your Start Menu is a shortcut and can be manipulated like any other shortcut (copied, moved, deleted, etc). With the Windows Start Menu (all version of Windows), Microsoft has decided that there be two parallel folder structures to store your Start Menu shortcuts.  One for you (the logged-in user of the computer) and one for all users of the computer.  Having two parallel structures can often be redundant:  If you are the only user of the computer, then having two parallel structures is totally redundant.  Even if you have several users that regularly log into the computer, most of your installed software will need to be made available to all users, and should thus be moved out of the “just you” version of the Start Menu and into the “all users” area. To take control of your Start Menu, so you can start organizing it, you’ll need to know how to access the actual folders and shortcut files that make up the Start Menu (both versions of it).  To find these folders and files, click the Start button and then right-click on the All Programs text (Windows XP users should right-click on the Start button itself): The Open option refers to the “just you” version of the Start Menu, while the Open All Users option refers to the “all users” version.  Click on the one you want to organize. A Windows Explorer window then opens with your chosen version of the Start Menu selected.  From there it’s easy.  Double-click on the Programs folder and you’ll see all your folders and shortcuts.  Now you can delete/rename/move until it’s just the way you want it. Note:  When you’re reorganizing your Start Menu, you may want to have two Explorer windows open at the same time – one showing the “just you” version and one showing the “all users” version.  You can drag-and-drop between the windows. Tip #20.  Keep Your Start Menu Tidy Once you have a perfectly organized Start Menu, try to be a little vigilant about keeping it that way.  Every time you install a new piece of software, the icons that get created will almost certainly violate your organizational structure. So to keep your Start Menu pristine and organized, make sure you do the following whenever you install a new piece of software: Check whether the software was installed into the “just you” area of the Start Menu, or the “all users” area, and then move it to the correct area. Remove all the unnecessary icons (like the “Read me” icon, the “Help” icon (you can always open the help from within the software itself when it’s running), the “Uninstall” icon, the link(s)to the manufacturer’s website, etc) Rename the main icon(s) of the software to something brief that makes sense to you.  For example, you might like to rename Microsoft Office Word 2010 to simply Word Move the icon(s) into the correct folder based on your Start Menu organizational structure And don’t forget:  when you uninstall a piece of software, the software’s uninstall routine is no longer going to be able to remove the software’s icon from the Start Menu (because you moved and/or renamed it), so you’ll need to remove that icon manually. Tip #21.  Tidy C:\ The root of your C: drive (C:\) is a common dumping ground for files and folders – both by the users of your computer and by the software that you install on your computer.  It can become a mess. There’s almost no software these days that requires itself to be installed in C:\.  99% of the time it can and should be installed into C:\Program Files.  And as for your own files, well, it’s clear that they can (and almost always should) be stored somewhere else. In an ideal world, your C:\ folder should look like this (on Windows 7): Note that there are some system files and folders in C:\ that are usually and deliberately “hidden” (such as the Windows virtual memory file pagefile.sys, the boot loader file bootmgr, and the System Volume Information folder).  Hiding these files and folders is a good idea, as they need to stay where they are and are almost never needed to be opened or even seen by you, the user.  Hiding them prevents you from accidentally messing with them, and enhances your sense of order and well-being when you look at your C: drive folder. Tip #22.  Tidy Your Desktop The Desktop is probably the most abused part of a Windows computer (from an organization point of view).  It usually serves as a dumping ground for all incoming files, as well as holding icons to oft-used applications, plus some regularly opened files and folders.  It often ends up becoming an uncontrolled mess.  See if you can avoid this.  Here’s why… Application icons (Word, Internet Explorer, etc) are often found on the Desktop, but it’s unlikely that this is the optimum place for them.  The “Quick Launch” bar (or the Superbar in Windows 7) is always visible and so represents a perfect location to put your icons.  You’ll only be able to see the icons on your Desktop when all your programs are minimized.  It might be time to get your application icons off your desktop… You may have decided that the Inbox/To-do folder on your computer (see tip #13, above) should be your Desktop.  If so, then enough said.  Simply be vigilant about clearing it and preventing it from being polluted by junk files (see tip #15, above).  On the other hand, if your Desktop is not acting as your “Inbox” folder, then there’s no reason for it to have any data files or folders on it at all, except perhaps a couple of shortcuts to often-opened files and folders (either ongoing or current projects).  Everything else should be moved to your “Inbox” folder. In an ideal world, it might look like this: Tip #23.  Move Permanent Items on Your Desktop Away from the Top-Left Corner When files/folders are dragged onto your desktop in a Windows Explorer window, or when shortcuts are created on your Desktop from Internet Explorer, those icons are always placed in the top-left corner – or as close as they can get.  If you have other files, folders or shortcuts that you keep on the Desktop permanently, then it’s a good idea to separate these permanent icons from the transient ones, so that you can quickly identify which ones the transients are.  An easy way to do this is to move all your permanent icons to the right-hand side of your Desktop.  That should keep them separated from incoming items. Tip #24.  Synchronize If you have more than one computer, you’ll almost certainly want to share files between them.  If the computers are permanently attached to the same local network, then there’s no need to store multiple copies of any one file or folder – shortcuts will suffice.  However, if the computers are not always on the same network, then you will at some point need to copy files between them.  For files that need to permanently live on both computers, the ideal way to do this is to synchronize the files, as opposed to simply copying them. We only have room here to write a brief summary of synchronization, not a full article.  In short, there are several different types of synchronization: Where the contents of one folder are accessible anywhere, such as with Dropbox Where the contents of any number of folders are accessible anywhere, such as with Windows Live Mesh Where any files or folders from anywhere on your computer are synchronized with exactly one other computer, such as with the Windows “Briefcase”, Microsoft SyncToy, or (much more powerful, yet still free) SyncBack from 2BrightSparks.  This only works when both computers are on the same local network, at least temporarily. A great advantage of synchronization solutions is that once you’ve got it configured the way you want it, then the sync process happens automatically, every time.  Click a button (or schedule it to happen automatically) and all your files are automagically put where they’re supposed to be. If you maintain the same file and folder structure on both computers, then you can also sync files depend upon the correct location of other files, like shortcuts, playlists and office documents that link to other office documents, and the synchronized files still work on the other computer! Tip #25.  Hide Files You Never Need to See If you have your files well organized, you will often be able to tell if a file is out of place just by glancing at the contents of a folder (for example, it should be pretty obvious if you look in a folder that contains all the MP3s from one music CD and see a Word document in there).  This is a good thing – it allows you to determine if there are files out of place with a quick glance.  Yet sometimes there are files in a folder that seem out of place but actually need to be there, such as the “folder art” JPEGs in music folders, and various files in the root of the C: drive.  If such files never need to be opened by you, then a good idea is to simply hide them.  Then, the next time you glance at the folder, you won’t have to remember whether that file was supposed to be there or not, because you won’t see it at all! To hide a file, simply right-click on it and choose Properties: Then simply tick the Hidden tick-box:   Tip #26.  Keep Every Setup File These days most software is downloaded from the Internet.  Whenever you download a piece of software, keep it.  You’ll never know when you need to reinstall the software. Further, keep with it an Internet shortcut that links back to the website where you originally downloaded it, in case you ever need to check for updates. See tip #33 below for a full description of the excellence of organizing your setup files. Tip #27.  Try to Minimize the Number of Folders that Contain Both Files and Sub-folders Some of the folders in your organizational structure will contain only files.  Others will contain only sub-folders.  And you will also have some folders that contain both files and sub-folders.  You will notice slight improvements in how long it takes you to locate a file if you try to avoid this third type of folder.  It’s not always possible, of course – you’ll always have some of these folders, but see if you can avoid it. One way of doing this is to take all the leftover files that didn’t end up getting stored in a sub-folder and create a special “Miscellaneous” or “Other” folder for them. Tip #28.  Starting a Filename with an Underscore Brings it to the Top of a List Further to the previous tip, if you name that “Miscellaneous” or “Other” folder in such a way that its name begins with an underscore “_”, then it will appear at the top of the list of files/folders. The screenshot below is an example of this.  Each folder in the list contains a set of digital photos.  The folder at the top of the list, _Misc, contains random photos that didn’t deserve their own dedicated folder: Tip #29.  Clean Up those CD-ROMs and (shudder!) Floppy Disks Have you got a pile of CD-ROMs stacked on a shelf of your office?  Old photos, or files you archived off onto CD-ROM (or even worse, floppy disks!) because you didn’t have enough disk space at the time?  In the meantime have you upgraded your computer and now have 500 Gigabytes of space you don’t know what to do with?  If so, isn’t it time you tidied up that stack of disks and filed them into your gorgeous new folder structure? So what are you waiting for?  Bite the bullet, copy them all back onto your computer, file them in their appropriate folders, and then back the whole lot up onto a shiny new 1000Gig external hard drive! Useful Folders to Create This next section suggests some useful folders that you might want to create within your folder structure.  I’ve personally found them to be indispensable. The first three are all about convenience – handy folders to create and then put somewhere that you can always access instantly.  For each one, it’s not so important where the actual folder is located, but it’s very important where you put the shortcut(s) to the folder.  You might want to locate the shortcuts: On your Desktop In your “Quick Launch” area (or pinned to your Windows 7 Superbar) In your Windows Explorer “Favorite Links” area Tip #30.  Create an “Inbox” (“To-Do”) Folder This has already been mentioned in depth (see tip #13), but we wanted to reiterate its importance here.  This folder contains all the recently created, received or downloaded files that you have not yet had a chance to file away properly, and it also may contain files that you have yet to process.  In effect, it becomes a sort of “to-do list”.  It doesn’t have to be called “Inbox” – you can call it whatever you want. Tip #31.  Create a Folder where Your Current Projects are Collected Rather than going hunting for them all the time, or dumping them all on your desktop, create a special folder where you put links (or work folders) for each of the projects you’re currently working on. You can locate this folder in your “Inbox” folder, on your desktop, or anywhere at all – just so long as there’s a way of getting to it quickly, such as putting a link to it in Windows Explorer’s “Favorite Links” area: Tip #32.  Create a Folder for Files and Folders that You Regularly Open You will always have a few files that you open regularly, whether it be a spreadsheet of your current accounts, or a favorite playlist.  These are not necessarily “current projects”, rather they’re simply files that you always find yourself opening.  Typically such files would be located on your desktop (or even better, shortcuts to those files).  Why not collect all such shortcuts together and put them in their own special folder? As with the “Current Projects” folder (above), you would want to locate that folder somewhere convenient.  Below is an example of a folder called “Quick links”, with about seven files (shortcuts) in it, that is accessible through the Windows Quick Launch bar: See tip #37 below for a full explanation of the power of the Quick Launch bar. Tip #33.  Create a “Set-ups” Folder A typical computer has dozens of applications installed on it.  For each piece of software, there are often many different pieces of information you need to keep track of, including: The original installation setup file(s).  This can be anything from a simple 100Kb setup.exe file you downloaded from a website, all the way up to a 4Gig ISO file that you copied from a DVD-ROM that you purchased. The home page of the software manufacturer (in case you need to look up something on their support pages, their forum or their online help) The page containing the download link for your actual file (in case you need to re-download it, or download an upgraded version) The serial number Your proof-of-purchase documentation Any other template files, plug-ins, themes, etc that also need to get installed For each piece of software, it’s a great idea to gather all of these files together and put them in a single folder.  The folder can be the name of the software (plus possibly a very brief description of what it’s for – in case you can’t remember what the software does based in its name).  Then you would gather all of these folders together into one place, and call it something like “Software” or “Setups”. If you have enough of these folders (I have several hundred, being a geek, collected over 20 years), then you may want to further categorize them.  My own categorization structure is based on “platform” (operating system): The last seven folders each represents one platform/operating system, while _Operating Systems contains set-up files for installing the operating systems themselves.  _Hardware contains ROMs for hardware I own, such as routers. Within the Windows folder (above), you can see the beginnings of the vast library of software I’ve compiled over the years: An example of a typical application folder looks like this: Tip #34.  Have a “Settings” Folder We all know that our documents are important.  So are our photos and music files.  We save all of these files into folders, and then locate them afterwards and double-click on them to open them.  But there are many files that are important to us that can’t be saved into folders, and then searched for and double-clicked later on.  These files certainly contain important information that we need, but are often created internally by an application, and saved wherever that application feels is appropriate. A good example of this is the “PST” file that Outlook creates for us and uses to store all our emails, contacts, appointments and so forth.  Another example would be the collection of Bookmarks that Firefox stores on your behalf. And yet another example would be the customized settings and configuration files of our all our software.  Granted, most Windows programs store their configuration in the Registry, but there are still many programs that use configuration files to store their settings. Imagine if you lost all of the above files!  And yet, when people are backing up their computers, they typically only back up the files they know about – those that are stored in the “My Documents” folder, etc.  If they had a hard disk failure or their computer was lost or stolen, their backup files would not include some of the most vital files they owned.  Also, when migrating to a new computer, it’s vital to ensure that these files make the journey. It can be a very useful idea to create yourself a folder to store all your “settings” – files that are important to you but which you never actually search for by name and double-click on to open them.  Otherwise, next time you go to set up a new computer just the way you want it, you’ll need to spend hours recreating the configuration of your previous computer! So how to we get our important files into this folder?  Well, we have a few options: Some programs (such as Outlook and its PST files) allow you to place these files wherever you want.  If you delve into the program’s options, you will find a setting somewhere that controls the location of the important settings files (or “personal storage” – PST – when it comes to Outlook) Some programs do not allow you to change such locations in any easy way, but if you get into the Registry, you can sometimes find a registry key that refers to the location of the file(s).  Simply move the file into your Settings folder and adjust the registry key to refer to the new location. Some programs stubbornly refuse to allow their settings files to be placed anywhere other then where they stipulate.  When faced with programs like these, you have three choices:  (1) You can ignore those files, (2) You can copy the files into your Settings folder (let’s face it – settings don’t change very often), or (3) you can use synchronization software, such as the Windows Briefcase, to make synchronized copies of all your files in your Settings folder.  All you then have to do is to remember to run your sync software periodically (perhaps just before you run your backup software!). There are some other things you may decide to locate inside this new “Settings” folder: Exports of registry keys (from the many applications that store their configurations in the Registry).  This is useful for backup purposes or for migrating to a new computer Notes you’ve made about all the specific customizations you have made to a particular piece of software (so that you’ll know how to do it all again on your next computer) Shortcuts to webpages that detail how to tweak certain aspects of your operating system or applications so they are just the way you like them (such as how to remove the words “Shortcut to” from the beginning of newly created shortcuts).  In other words, you’d want to create shortcuts to half the pages on the How-To Geek website! Here’s an example of a “Settings” folder: Windows Features that Help with Organization This section details some of the features of Microsoft Windows that are a boon to anyone hoping to stay optimally organized. Tip #35.  Use the “Favorite Links” Area to Access Oft-Used Folders Once you’ve created your great new filing system, work out which folders you access most regularly, or which serve as great starting points for locating the rest of the files in your folder structure, and then put links to those folders in your “Favorite Links” area of the left-hand side of the Windows Explorer window (simply called “Favorites” in Windows 7):   Some ideas for folders you might want to add there include: Your “Inbox” folder (or whatever you’ve called it) – most important! The base of your filing structure (e.g. C:\Files) A folder containing shortcuts to often-accessed folders on other computers around the network (shown above as Network Folders) A folder containing shortcuts to your current projects (unless that folder is in your “Inbox” folder) Getting folders into this area is very simple – just locate the folder you’re interested in and drag it there! Tip #36.  Customize the Places Bar in the File/Open and File/Save Boxes Consider the screenshot below: The highlighted icons (collectively known as the “Places Bar”) can be customized to refer to any folder location you want, allowing instant access to any part of your organizational structure. Note:  These File/Open and File/Save boxes have been superseded by new versions that use the Windows Vista/Windows 7 “Favorite Links”, but the older versions (shown above) are still used by a surprisingly large number of applications. The easiest way to customize these icons is to use the Group Policy Editor, but not everyone has access to this program.  If you do, open it up and navigate to: User Configuration > Administrative Templates > Windows Components > Windows Explorer > Common Open File Dialog If you don’t have access to the Group Policy Editor, then you’ll need to get into the Registry.  Navigate to: HKEY_CURRENT_USER \ Software \ Microsoft  \ Windows \ CurrentVersion \ Policies \ comdlg32 \ Placesbar It should then be easy to make the desired changes.  Log off and log on again to allow the changes to take effect. Tip #37.  Use the Quick Launch Bar as a Application and File Launcher That Quick Launch bar (to the right of the Start button) is a lot more useful than people give it credit for.  Most people simply have half a dozen icons in it, and use it to start just those programs.  But it can actually be used to instantly access just about anything in your filing system: For complete instructions on how to set this up, visit our dedicated article on this topic. Tip #38.  Put a Shortcut to Windows Explorer into Your Quick Launch Bar This is only necessary in Windows Vista and Windows XP.  The Microsoft boffins finally got wise and added it to the Windows 7 Superbar by default. Windows Explorer – the program used for managing your files and folders – is one of the most useful programs in Windows.  Anyone who considers themselves serious about being organized needs instant access to this program at any time.  A great place to create a shortcut to this program is in the Windows XP and Windows Vista “Quick Launch” bar: To get it there, locate it in your Start Menu (usually under “Accessories”) and then right-drag it down into your Quick Launch bar (and create a copy). Tip #39.  Customize the Starting Folder for Your Windows 7 Explorer Superbar Icon If you’re on Windows 7, your Superbar will include a Windows Explorer icon.  Clicking on the icon will launch Windows Explorer (of course), and will start you off in your “Libraries” folder.  Libraries may be fine as a starting point, but if you have created yourself an “Inbox” folder, then it would probably make more sense to start off in this folder every time you launch Windows Explorer. To change this default/starting folder location, then first right-click the Explorer icon in the Superbar, and then right-click Properties:Then, in Target field of the Windows Explorer Properties box that appears, type %windir%\explorer.exe followed by the path of the folder you wish to start in.  For example: %windir%\explorer.exe C:\Files If that folder happened to be on the Desktop (and called, say, “Inbox”), then you would use the following cleverness: %windir%\explorer.exe shell:desktop\Inbox Then click OK and test it out. Tip #40.  Ummmmm…. No, that’s it.  I can’t think of another one.  That’s all of the tips I can come up with.  I only created this one because 40 is such a nice round number… Case Study – An Organized PC To finish off the article, I have included a few screenshots of my (main) computer (running Vista).  The aim here is twofold: To give you a sense of what it looks like when the above, sometimes abstract, tips are applied to a real-life computer, and To offer some ideas about folders and structure that you may want to steal to use on your own PC. Let’s start with the C: drive itself.  Very minimal.  All my files are contained within C:\Files.  I’ll confine the rest of the case study to this folder: That folder contains the following: Mark: My personal files VC: My business (Virtual Creations, Australia) Others contains files created by friends and family Data contains files from the rest of the world (can be thought of as “public” files, usually downloaded from the Net) Settings is described above in tip #34 The Data folder contains the following sub-folders: Audio:  Radio plays, audio books, podcasts, etc Development:  Programmer and developer resources, sample source code, etc (see below) Humour:  Jokes, funnies (those emails that we all receive) Movies:  Downloaded and ripped movies (all legal, of course!), their scripts, DVD covers, etc. Music:  (see below) Setups:  Installation files for software (explained in full in tip #33) System:  (see below) TV:  Downloaded TV shows Writings:  Books, instruction manuals, etc (see below) The Music folder contains the following sub-folders: Album covers:  JPEG scans Guitar tabs:  Text files of guitar sheet music Lists:  e.g. “Top 1000 songs of all time” Lyrics:  Text files MIDI:  Electronic music files MP3 (representing 99% of the Music folder):  MP3s, either ripped from CDs or downloaded, sorted by artist/album name Music Video:  Video clips Sheet Music:  usually PDFs The Data\Writings folder contains the following sub-folders: (all pretty self-explanatory) The Data\Development folder contains the following sub-folders: Again, all pretty self-explanatory (if you’re a geek) The Data\System folder contains the following sub-folders: These are usually themes, plug-ins and other downloadable program-specific resources. The Mark folder contains the following sub-folders: From Others:  Usually letters that other people (friends, family, etc) have written to me For Others:  Letters and other things I have created for other people Green Book:  None of your business Playlists:  M3U files that I have compiled of my favorite songs (plus one M3U playlist file for every album I own) Writing:  Fiction, philosophy and other musings of mine Mark Docs:  Shortcut to C:\Users\Mark Settings:  Shortcut to C:\Files\Settings\Mark The Others folder contains the following sub-folders: The VC (Virtual Creations, my business – I develop websites) folder contains the following sub-folders: And again, all of those are pretty self-explanatory. Conclusion These tips have saved my sanity and helped keep me a productive geek, but what about you? What tips and tricks do you have to keep your files organized?  Please share them with us in the comments.  Come on, don’t be shy… Similar Articles Productive Geek Tips Fix For When Windows Explorer in Vista Stops Showing File NamesWhy Did Windows Vista’s Music Folder Icon Turn Yellow?Print or Create a Text File List of the Contents in a Directory the Easy WayCustomize the Windows 7 or Vista Send To MenuAdd Copy To / Move To on Windows 7 or Vista Right-Click Menu TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Track Daily Goals With 42Goals Video Toolbox is a Superb Online Video Editor Fun with 47 charts and graphs Tomorrow is Mother’s Day Check the Average Speed of YouTube Videos You’ve Watched OutlookStatView Scans and Displays General Usage Statistics

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  • Agile Development

    - by James Oloo Onyango
    Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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  • Coupling/Cohesion

    - by user559142
    Hi All, Whilst there are many good examples on this forum that contain examples of coupling and cohesion, I am struggling to apply it to my code fully. I can identify parts in my code that may need changing. Would any Java experts be able to take a look at my code and explain to me what aspects are good and bad. I don't mind changing it myself at all. It's just that many people seem to disagree with each other and I'm finding it hard to actually understand what principles to follow... package familytree; /** * * @author David */ public class Main { /** * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic here KeyboardInput in = new KeyboardInput(); FamilyTree familyTree = new FamilyTree(in, System.out); familyTree.start(); } } package familytree; import java.io.PrintStream; /** * * @author David */ public class FamilyTree { /** * @param args the command line arguments */ private static final int DISPLAY_FAMILY_MEMBERS = 1; private static final int ADD_FAMILY_MEMBER = 2; private static final int REMOVE_FAMILY_MEMBER = 3; private static final int EDIT_FAMILY_MEMBER = 4; private static final int SAVE_FAMILY_TREE = 5; private static final int LOAD_FAMILY_TREE = 6; private static final int DISPLAY_ANCESTORS = 7; private static final int DISPLAY_DESCENDANTS = 8; private static final int QUIT = 9; private KeyboardInput in; private Family family; private PrintStream out; public FamilyTree(KeyboardInput in, PrintStream out) { this.in = in; this.out = out; family = new Family(); } public void start() { out.println("\nWelcome to the Family Tree Builder"); //enterUserDetails(); initialise(); while (true) { displayFamilyTreeMenu(); out.print("\nEnter Choice: "); int option = in.readInteger(); if (option > 0 && option <= 8) { if (quit(option)) { break; } executeOption(option); } else { out.println("Invalid Choice!"); } } } //good private void displayFamilyTreeMenu() { out.println("\nFamily Tree Menu"); out.println(DISPLAY_FAMILY_MEMBERS + ". Display Family Members"); out.println(ADD_FAMILY_MEMBER + ". Add Family Member"); out.println(REMOVE_FAMILY_MEMBER + ". Remove Family Member"); out.println(EDIT_FAMILY_MEMBER + ". Edit Family Member"); out.println(SAVE_FAMILY_TREE + ". Save Family Tree"); out.println(LOAD_FAMILY_TREE + ". Load Family Tree"); out.println(DISPLAY_ANCESTORS + ". Display Ancestors"); out.println(DISPLAY_DESCENDANTS + ". Display Descendants"); out.println(QUIT + ". Quit"); } //good private boolean quit(int opt) { return (opt == QUIT) ? true : false; } //good private void executeOption(int choice) { switch (choice) { case DISPLAY_FAMILY_MEMBERS: displayFamilyMembers(); break; case ADD_FAMILY_MEMBER: addFamilyMember(); break; case REMOVE_FAMILY_MEMBER: break; case EDIT_FAMILY_MEMBER: break; case SAVE_FAMILY_TREE: break; case LOAD_FAMILY_TREE: break; case DISPLAY_ANCESTORS: displayAncestors(); break; case DISPLAY_DESCENDANTS: displayDescendants(); break; default: out.println("Not a valid option! Try again."); break; } } //for selecting family member for editing adding nodes etc private void displayFamilyMembers() { out.println("\nDisplay Family Members"); int count = 0; for (FamilyMember member : family.getFamilyMembers()) { out.println(); if (count + 1 < 10) { out.println((count + 1) + ". " + member.getFirstName() + " " + member.getLastName()); out.println(" " + member.getDob()); out.println(" Generation: " + member.getGeneration()); } else { out.println((count + 1) + ". " + member.getFirstName() + " " + member.getLastName()); out.println(" " + member.getDob()); out.println(" Generation: " + member.getGeneration()); } count++; } } private int selectRelative() { out.println("\nSelect Relative"); out.println("1. Add Parents"); out.println("2. Add Child"); out.println("3. Add Partner"); out.println("4. Add Sibling"); out.print("\nEnter Choice: "); int choice = in.readInteger(); if (choice > 0 && choice < 5) { return choice; } return (-1); } private void addFamilyMember() { int memberIndex = selectMember(); if (memberIndex >= 0) { FamilyMember member = family.getFamilyMember(memberIndex); int relative = selectRelative(); if (relative > 0) { out.println("\nAdd Member"); //if choice is valid switch (relative) { case 1: //adding parents if (member.getFather() == null) { FamilyMember mum, dad; out.println("Enter Mothers Details"); mum = addMember(relative, "Female"); out.println("\nEnter Fathers Details"); dad = addMember(relative, "Male"); member.linkParent(mum); member.linkParent(dad); mum.linkPartner(dad); mum.setGeneration(member.getGeneration() - 1); dad.setGeneration(member.getGeneration() - 1); sortGenerations(); } else { out.println(member.getFirstName() + " " + member.getLastName() + " already has parents."); } break; case 2: //adding child if (member.getPartner() == null) { FamilyMember partner; if (member.getGender().equals("Male")) { out.println("Enter Mothers Details"); partner = addMember(1, "Female"); } else { out.println("Enter Fathers Details"); partner = addMember(1, "Male"); } //create partner member.linkPartner(partner); partner.setGeneration(member.getGeneration()); out.println(); } out.println("Enter Childs Details"); FamilyMember child = addMember(relative, ""); child.linkParent(member); child.linkParent(member.getPartner()); child.setGeneration(member.getGeneration() + 1); sortGenerations(); break; case 3: //adding partner if (member.getPartner() == null) { out.println("Enter Partners Details"); FamilyMember partner = addMember(relative, ""); member.linkPartner(partner); partner.setGeneration(member.getGeneration()); } else { out.println(member.getFirstName() + " " + member.getLastName() + " already has a partner."); } break; case 4: //adding sibling FamilyMember mum, dad; if (member.getFather() == null) { out.println("Enter Mothers Details"); mum = addMember(1, "Female"); out.println("\nEnter Fathers Details"); dad = addMember(1, "Male"); member.linkParent(mum); member.linkParent(dad); mum.linkPartner(dad); mum.setGeneration(member.getGeneration() - 1); dad.setGeneration(member.getGeneration() - 1); sortGenerations(); out.println("\nEnter Siblings Details"); } else { out.println("Enter Siblings Details"); } FamilyMember sibling = addMember(relative, ""); //create mum and dad mum = member.getMother(); dad = member.getFather(); sibling.linkParent(mum); sibling.linkParent(dad); sibling.setGeneration(member.getGeneration()); break; } } else { out.println("Invalid Option!"); } } else { out.println("Invalid Option!"); } } private int selectMember() { displayFamilyMembers(); out.print("\nSelect Member: "); int choice = in.readInteger(); if (choice > 0 && choice <= family.getFamilyMembers().size()) { return (choice - 1); } return -1; } private FamilyMember addMember(int option, String gender) { out.print("Enter First Name: "); String fName = formatString(in.readString().trim()); out.print("Enter Last Name: "); String lName = formatString(in.readString().trim()); if (option != 1) { //if not adding parents out.println("Select Gender"); out.println("1. Male"); out.println("2. Female"); out.print("Enter Choice: "); int gOpt = in.readInteger(); if (gOpt == 1) { gender = "Male"; } else if (gOpt == 2) { gender = "Female"; } else { out.println("Invalid Choice"); return null; } } String dob = enterDateOfBirth(); lName = formatString(lName); FamilyMember f = family.getFamilyMember(family.addMember(fName, lName, gender, dob)); f.setIndex(family.getFamilyMembers().size() - 1); return (f); } private String formatString(String s){ String firstLetter = s.substring(0, 1); String remainingLetters = s.substring(1, s.length()); s = firstLetter.toUpperCase() + remainingLetters.toLowerCase(); return s; } private String enterDateOfBirth(){ out.print("Enter Year Of Birth (0 - 2011): "); String y = in.readString(); out.print("Enter Month Of Birth (1-12): "); String m = in.readString(); if (Integer.parseInt(m) < 10) { m = "0" + m; } m += "-"; out.print("Enter Date of Birth (1-31): "); String d = in.readString(); if (Integer.parseInt(d) < 10) { d = "0" + d; } d += "-"; String dob = d + m + y; while(!DateValidator.isValid(dob)){ out.println("Invalid Date. Try Again:"); dob = enterDateOfBirth(); } return (dob); } private void displayAncestors() { out.print("\nDisplay Ancestors For Which Member: "); int choice = selectMember(); if (choice >= 0) { FamilyMember node = family.getFamilyMember(choice ); FamilyMember ms = findRootNode(node, 0, 2, -1); FamilyMember fs = findRootNode(node, 1, 2, -1); out.println("\nPrint Ancestors"); out.println("\nMothers Side"); printDescendants(ms, node, ms.getGeneration()); out.println("\nFathers Side"); printDescendants(fs, node, fs.getGeneration()); } else { out.println("Invalid Option!"); } } private void displayDescendants() { out.print("\nDisplay Descendants For Which Member: "); int choice = selectMember(); if (choice >= 0) { FamilyMember node = family.getFamilyMember(choice); out.println("\nPrint Descendants"); printDescendants(node, null, 0); } else { out.println("Invalid Option!"); } } private FamilyMember findRootNode(FamilyMember node, int parent, int numGenerations, int count) { FamilyMember root; count++; if (node.hasParents() && count < numGenerations) { if (parent == 0) { node = node.getMother(); root = findRootNode(node, 1, numGenerations, count); } else { node = node.getFather(); root = findRootNode(node, 1, numGenerations, count); } return root; } return node; } private int findHighestLeafGeneration(FamilyMember node) { int gen = node.getGeneration(); for (int i = 0; i < node.getChildren().size(); i++) { int highestChild = findHighestLeafGeneration(node.getChild(i)); if (highestChild > gen) { gen = highestChild; } } return gen; } private void printDescendants(FamilyMember root, FamilyMember node, int gen) { out.print((root.getGeneration() + 1) + " " + root.getFullName()); out.print(" [" + root.getDob() + "] "); if (root.getPartner() != null) { out.print("+Partner: " + root.getPartner().getFullName() + " [" + root.getPartner().getDob() + "] "); } if (root == node) { out.print("*"); } out.println(); if (!root.getChildren().isEmpty() && root != node) { for (int i = 0; i < root.getChildren().size(); i++) { for (int j = 0; j < root.getChild(i).getGeneration() - gen; j++) { out.print(" "); } printDescendants(root.getChild(i), node, gen); } } else { return; } } //retrieve highest generation public int getRootGeneration(){ int min = family.getFamilyMember(0).getGeneration(); for(int i = 0; i < family.getFamilyMembers().size(); i++){ min = Math.min(min, family.getFamilyMember(i).getGeneration()); } return Math.abs(min); } public void sortGenerations(){ int amount = getRootGeneration(); for (FamilyMember member : family.getFamilyMembers()) { member.setGeneration(member.getGeneration() + amount); } } //test method - temporary private void initialise() { family.addMember("Bilbo", "Baggins", "Male", "23-06-1920"); } } package familytree; import java.util.ArrayList; import java.util.Date; /** * * @author David */ public class Family { //family members private ArrayList<FamilyMember> family; //create Family public Family() { family = new ArrayList<FamilyMember>(); } //add member to the family public int addMember(String f, String l, String g, String d) { family.add(new FamilyMember(f, l, g, d)); return family.size()-1; } //remove member from family public void removeMember(int index) { family.remove(index); } public FamilyMember getFamilyMember(int index) { return family.get(index); } //return family public ArrayList <FamilyMember> getFamilyMembers() { return family; } public void changeFirstName(int index, String f) { family.get(index).setFirstName(f);//change to setfirstname and others } public void changeLastName(int index, String l) { family.get(index).setLastName(l); } public void changeAge(int index, int a) { family.get(index).setAge(a); } public void changeDOB() { //implement } } package familytree; import java.util.ArrayList; import java.util.Collections; /** * * @author David */ public class FamilyMember extends Person { private FamilyMember mother; private FamilyMember father; private FamilyMember partner; private ArrayList<FamilyMember> children; private int generation; private int index; //initialise family member public FamilyMember(String f, String l, String g, String d) { super(f, l, g, d); mother = null; father = null; partner = null; children = new ArrayList<FamilyMember>(); generation = 0; index = -1; } public void linkParent(FamilyMember parent) { if (parent.getGender().equals("Female")) { this.setMother(parent); } else { this.setFather(parent); } parent.addChild(this); } public void linkPartner(FamilyMember partner) { partner.setPartner(this); this.setPartner(partner); } public boolean hasParents() { if (this.getMother() == null && this.getFather() == null) { return false; } return true; } public FamilyMember getMother() { return mother; } public FamilyMember getFather() { return father; } public FamilyMember getPartner() { return partner; } public FamilyMember getChild(int index) { return children.get(index); } public int getGeneration() { return generation; } public int getIndex() { return index; } public ArrayList<FamilyMember> getChildren() { return children; } public void setMother(FamilyMember f) { mother = f; } public void setFather(FamilyMember f) { father = f; } public void setPartner(FamilyMember f) { partner = f; } public void addChild(FamilyMember f) { children.add(f); //add child if(children.size() > 1){ //sort in ascending order Collections.sort(children, new DateComparator()); } } public void addChildAt(FamilyMember f, int index) { children.set(index, f); } public void setGeneration(int g) { generation = g; } public void setIndex(int i){ index = i; } } package familytree; /** * * @author David */ public class Person{ private String fName; private String lName; private String gender; private int age; private String dob; public Person(String fName, String lName, String gender, String dob){ this.fName = fName; this.lName = lName; this.gender = gender; this.dob = dob; } public String getFullName(){ return (this.fName + " " + this.lName); } public String getFirstName(){ return (fName); } public String getLastName(){ return (lName); } public String getGender(){ return (gender); } public String getDob(){ return dob; } public int getAge(){ return age; } public void setFirstName(String fName){ this.fName = fName; } public void setLastName(String lName){ this.lName = lName; } public void setGender(String gender){ this.gender = gender; } public void setAge(int age){ this.age = age; } }

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  • What are good design practices when working with Entity Framework

    - by AD
    This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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