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• Best system for creating a 2d racing track

  - by tesselode

  I am working a 2D racing game and I'm trying to figure out what is the best way to define the track. At the very least, I need to be able to create a closed circuit with any amount of turns at any angle, and I need vehicles to collide with the edges of the track. I also want the following things to be true if possible (but they are optional): The code is simple and free of funky workarounds and extras I can define all of the parts of the track (such as turns) relative to the previous parts I can predict the exact position of the road at a certain point (that way I can easily and cleanly make closed circuits) Here are my options: Use a set of points. This is my current system. I have a set of turns and width changes that the track is supposed to make over time. I have a point which I transform according to these instructions, and I place a point every 5 steps or so, depending on how precise I want the track to be. These points make up the track. The main problem with this is the discrepancy between the collisions and the way the track is drawn. I won't get into too much detail, but the picture below shows what is happening (although it is exaggerated a bit). The blue lines are what is drawn, the red lines are what the vehicle collides with. I could work around this, but I'd rather avoid funky workaround code. Beizer curves. These seem cool, but my first impression of them is that they'll be a little daunting to learn and are probably too complicated for my needs. Some other kind of curve? I have heard of some other kinds of curves; maybe those are more applicable. Use Box2D or another physics engine. Instead of defining the center of the track, I could use a physics engine to define shapes that make up the road. The downside to this, however, is that I have to put in a little more work to place the checkpoints. Something completely different. Basically, what is the simplest system for generating a race track that would allow me to create closed circuits cleanly, handle collisions, and not have a ton of weird code?

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• Collaborative work (small team) - Best practices

  - by LEM01

  I'm currently working in a very small team of programmers (2-3) and I'm looking for advices/best practices on how to organise our work. We're all working on the same application using PHP. Today we're kind of all working on our way. Today situation: List item that have to be worked on by each dev 1/week. What has to be done is defined at a high functional level (ex: Build the search engine for this product..) Commit / merge our individual branches (git) every week before the next meeting No real dev rules, no code review No test written (aouutch) Problems faced: Code quality issue: discovering someone else code is sometime tough (inline, variable+function+class names, spaces, comments..) Changes in already existing classes (impact on someone else work) Responsibility of each dev unclear: after getting someone else code and discover something messy, should I make the change? Should he make the change? How to plan those things,... What I'm looking for: Basically I'm looking into structuring the way we develop things in order to avoid frustration and improve overall quality. How to define coding standards (naming convention, code rules...)? Do you you any validation script to make sure code is valid before committing? Do you think that defining an architect role in the team is needed? Someone that would actually define what has to be developed during the next phase. By defining interfaces or class descriptions that have to be written. (Does it make sense in such a small team?) Today we're losing time into understanding what others did or tried to do, we're also losing time in discussion like "you should have done it that way! Why is this class doing that and not that..? Shouldn't we have a embedded class rather that this set of data...". I'm looking into a work process, maybe with more defined responsibilities and process in order to improve our performance. If you have experience, advices, best practices or anything to share that we could benefit from it will be much appreciated! Thanks a lot for your time!

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• Why are MVC & TDD not employed more in game architecture?

  - by secoif

  I will preface this by saying I haven't looked a huge amount of game source, nor built much in the way of games. But coming from trying to employ 'enterprise' coding practices in web apps, looking at game source code seriously hurts my head: "What is this view logic doing in with business logic? this needs refactoring... so does this, refactor, refactorrr" This worries me as I'm about to start a game project, and I'm not sure whether trying to mvc/tdd the dev process is going to hinder us or help us, as I don't see many game examples that use this or much push for better architectural practices it in the community. The following is an extract from a great article on prototyping games, though to me it seemed exactly the attitude many game devs seem to use when writing production game code: Mistake #4: Building a system, not a game ...if you ever find yourself working on something that isn’t directly moving your forward, stop right there. As programmers, we have a tendency to try to generalize our code, and make it elegant and be able to handle every situation. We find that an itch terribly hard not scratch, but we need to learn how. It took me many years to realize that it’s not about the code, it’s about the game you ship in the end. Don’t write an elegant game component system, skip the editor completely and hardwire the state in code, avoid the data-driven, self-parsing, XML craziness, and just code the damned thing. ... Just get stuff on the screen as quickly as you can. And don’t ever, ever, use the argument “if we take some extra time and do this the right way, we can reuse it in the game”. EVER. is it because games are (mostly) visually oriented so it makes sense that the code will be weighted heavily in the view, thus any benefits from moving stuff out to models/controllers, is fairly minimal, so why bother? I've heard the argument that MVC introduces a performance overhead, but this seems to me to be a premature optimisation, and that there'd more important performance issues to tackle before you worry about MVC overheads (eg render pipeline, AI algorithms, datastructure traversal, etc). Same thing regarding TDD. It's not often I see games employing test cases, but perhaps this is due to the design issues above (mixed view/business) and the fact that it's difficult to test visual components, or components that rely on probablistic results (eg operate within physics simulations). Perhaps I'm just looking at the wrong source code, but why do we not see more of these 'enterprise' practices employed in game design? Are games really so different in their requirements, or is a people/culture issue (ie game devs come from a different background and thus have different coding habits)?

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• Criteria for a programming language to be considered "mature"

  - by Giorgio

  I was recently reading an answer to this question, and I was struck by the statement "The language is mature". So I was wondering what we actually mean when we say that "A programming language is mature"? Normally, a programming language is initially developed out of a need, e.g. Try out / implement a new programming paradigm or a new combination of features that cannot be found in existing languages. Try to solve a problem or overcome a limitation of an existing language. Create a language for teaching programming. Create a language that solves a particular class of problems (e.g. concurrency). Create a language and an API for a special application field, e.g. the web (in this case the language might reuse a well-known paradigm, but the whole API must be new). Create a language to push your competitor out of the market (in this case the creator might want the new language to be very similar to an existing one, in order to attract developers to the new programming language and platform). Regardless of what the original motivation and scenario in which a language has been created, eventually some languages are considered mature. In my intuition, this means that the language has achieved (at least one of) its goals, e.g. "We can now use language X as a reliable tool for writing web applications." This is however a bit vague, so I wanted to ask what you consider the most important criteria (if any) that are applied when saying that a language is mature. IMPORTANT NOTE This question is (on purpose) language-agnostic because I am only interested in general criteria. Please write only language-agnostic answers and comments! I am not asking whether any specific "language X is mature" or "which programming languages can be considered mature", or whether "language X is more mature than language Y": please avoid posting any opinions or reference about any specific languages because these are out of the scope of this question. EDIT To make the question more precise, by criteria I mean such things as "tool support", "adoption by the industry", "stability", "rich API", "large user community", "successful application record", "standardization", "clean and uniform semantics", and so on.

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• Practices for domain models in Javascript (with frameworks)

  - by AndyBursh

  This is a question I've to-and-fro'd with for a while, and searched for and found nothing on: what're the accepted practices surrounding duplicating domain models in Javascript for a web application, when using a framework like Backbone or Knockout? Given a web application of a non-trivial size with a set of domain models on the server side, should we duplicate these models in the web application (see the example at the bottom)? Or should we use the dynamic nature to load these models from the server? To my mind, the arguments for duplicating the models are in easing validation of fields, ensuring that fields that expected to be present are in fact present etc. My approach is to treat the client-side code like an almost separate application, doing trivial things itself and only relying on the server for data and complex operations (which require data the client-side doesn't have). I think treating the client-side code like this is akin to separation between entities from an ORM and the models used with the view in the UI layer: they may have the same fields and relate to the same domain concept, but they're distinct things. On the other hand, it seems to me that duplicating these models on the server side is a clear violation of DRY and likely to lead to differing results on the client- and server-side (where one piece gets updated but the other doesn't). To avoid this violation of DRY we can simply use Javascripts dynamism to get the field names and data from the server as and when they're neeed. So: are there any accepted guidelines around when (and when not) to repeat yourself in these situations? Or this a purely subjective thing, based on the project and developer(s)? Example Server-side model class M { int A DateTime B int C int D = (A*C) double SomeComplexCalculation = ServiceLayer.Call(); } Client-side model function M(){ this.A = ko.observable(); this.B = ko.observable(); this.C = ko.observable(); this.D = function() { return A() * C(); } this.SomeComplexCalculation = ko.observalbe(); return this; }l M.GetComplexValue = function(){ this.SomeComplexCalculation(Ajax.CallBackToServer()); }; I realise this question is quite similar to this one, but I think this is more about almost wholly untying the web application from the server, where that question is about doing this only in the case of complex calculation.

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• Determining whether a visitor reached two different pages in one visit

  - by Shaun

  I have a funnel that I would like to track. Tracking this funnel won't work with the default "goal funnel" tracking in Google due to the fact that I am mixing events and pageviews. As such, I've created a series of reports: Visits to demo pages - An inclusion filter on "Page". Triggers an Event on these pages - An inclusion filter on "Page" and "Event Category". Does not bounce - An inclusion filter on "Page" and an exclusion filter on "Exit Page" for these same pages. Reach our storefront - ?? Purchase something - An inclusion filter on "Page" and a report that shows "Transactions". At a basic level, I need to track users who reached demo pages, then reached any page on our store. Intuitively, I created a segment, used two inclusive "Page" filters (one for the demo pages and one for any page in our store), and combined them with an "AND" operator. I thought this was working until I tried to do the same thing in a dashboard widget and on a custom report. When I tried the same thing in those areas, I got zero results. I figured this might be because widgets and custom report filters function differently from segment filters (the options are different for all of them), so I tried applying my "demo page && store page" segment to a report that gave me a general page list. All I saw was a list of the specific pages. I tried simplifying things by creating a custom report that showed all visits to store pages, then applied a segment that filtered for users who visited demo pages. This got me the same numbers as my "demo page && store page" segment, but showed a list of demo pages. This has led me to believe that the "demo page && store page segment" approach and the "demo segment && store report" functionally behave the same. However, this experience has left me questioning whether they're giving me what I want. Are these methods showing me all users who reached both sets of pages? Is there a better/easier/more standard way of doing this aside from looking at visitor flow reports? I'm trying to avoid a combination of custom variables/events and using the horizontal funnel approach since it would consume a large number of our limited goals and seems more complicated than is necessary for tracking this funnel.

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• Working with Windows and Unix

  - by user554629

  Beware of new line characters One of the most frequent issues we encounter in Tech Support is the corruption of files that are transferred between Windows and Unix.   The transfer can occur at any stage, but ultimately involves a transfer of a file using an ftp client that is running on Windows;  it could be ftp or filezilla. Windows uses two characters to mark the end of a line in a text file (CR/LF),carriage return, linefeed.   Unix uses a single character (CR). In all situations, it is best to use binary mode transfer for all files, including ascii text files. Common problems: upload a core file from unix to windows using ftp in ascii mode.The file is going to be larger on Windows than Unix.ftp doesn't know if this is a text file with real line-ends, it takes every ascii CR and transmits two ascii characters CR/LF.The core file, tar file, library ... will be corrupted when transferred to Oracle. download a shell script to Windows, and transfer it to Unix using ftpIf the file is edited on Windows, the unix script line-end chars will be doubled.Unix doesn't know how to handle that, and will likely tell you the script is not executable.Why?  The first line of a shell script ( called "sh-bang" ), identifies the command interpreter the unix shell should use for this script.   Common examples:#/bin/sh#/bin/ksh#/bin/bash#/bin/perl#/bin/sh^M    # will not be understood.#/bin/env ksh # special syntax.  Find ksh and run it dos2unix is a common utility found on most unix platforms, that repairs the issue of Windows LineEnd characters in unix script files.   I've written my own flavor of this utility for use in Tech Support and build environments, that is a bit easier to use, and has some nice side-effects. accepts a list of files:   dos2unix *.sh repairs the file in-place.  Doesn't generate a new file you have to name retains the same timestamp;  it is the encoding that changed, not the file content. Here are the versions of dos2unix for each of the environments we work in.They are compressed with gzip, to avoid the ftp ascii transfer trap,and because I am quite limited in the number of files I can upload to this blog. AIX Linux Solaris sparc  Windows 

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• URL slugs: ideal length, and the real SEO effects of these slugs

  - by tattvamasi

  this question is addressed widely on SO and outside it, but for some reason, instead of taking it as a good load of great advice, all this information is confusing me. ** Problem ** I already had, on one of my sites, "prettified" urls. I had taken out the query strings, rewritten the URLS, and the link was short enough for me, but had a problem: the ID of the item or post in the URL isn't good for users. One of the users asked is there's a way to get rid of numbers, and I thought it was better for users to just see a clue of the page content in the URL. ** Solution ** With this in mind, I am trying with a section of the site.Armed with 301 redirects, some parsing work, and a lot of patience, I have added the URL slugs to some blog entries, and the slug of the URL reports the title of the article (something close to http://example.com/my-news/terribly-boring-and-long-url-that-replaces-the-number-I-liked-so-much/ ** Problems after Solution ** The problem, as I see it, is that now the URL of those blog articles is very descriptive for sure, but it is also impossible to remember. So, this brings me to the same issue I had with my previous problem: if numbers say nothing and can't be remembered, what's the use of these slugs? I prefer to see http://example.com/my-news/1/ than http://example.com/my-news/terribly-boring-and-long-url-that-replaces-the-number-I-liked-so-much/ To avoid forcing my user to memorize my URLS, I have added a script that finds the closest match to the URL you type, and redirects there. This is something I like, because the page now acts as a sort of little search engine, and users can play with the URLS to find articles. ** Open questions ** I still have some open questions, and don't seem to be able to find an answer, because answers tend to contradict one another. 1) How many characters should an URL ideally be long? I've read the magic number 115 and am sticking to that, but am not sure. 2) Is this really good for SEO? One of those blog articles I have redirected, with ID number in the URL and all, ranked second on Google. I've just found this question, and the answer seems to be consistent with what I think URL slug and SEO - structure (but see this other question with the opposite opinion) 3) To make a question with a specific example, would this URL risk to be penalized? Is it acceptable? Is it too long? StackOverflow seems to have comparably long URLs, but I'm not sure it's a winning strategy in my case. I just wanted to facilitate my users without running into Google's algorithms.

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• Advice on how to build html5 basic tile game (multi player, cross device)

  - by Eric

  I just read http://buildnewgames.com/real-time-multiplayer/ which explains the fundamentals and bets practices to build a massive real time multiplayer html5 game. My question is however given the “simplicity” of the game I need to build (simple kind of scratch game where you find or not something behind a tile), do I really need complex tools (canvas or node.js for example) ? The game The gamestakes place with a picture of our office as a background (tilemap). For HR purpose, we wish to create the following game fore employees: each day they can come to the website and click on a certain number of tiles (3 max per day) and find behind it motivation advice and interesting facts about the company. The constraints and rules the screen is divided into isometric 2D square tiles. There are basically an image (photograph of our office) number of tiles on the screen game: about 10,000 to much more (with scroll , see below) the players can scroll in 4 directions there are only 2 types of tiles: already open and closed player can open tiles that have not been yet open by other players there is no path for players : any player can click on any tile on the screen at any moment (if it’s not already done by another player) 2 players can’t be on the same tile at the same moment (or if they can, I’ll have to manage to see which one clicked on it first) only one type of player (all with similar roles), no weapon, no internal score… very simple game. no complex physics (collision only occurs if 2 players are on the same tile) The target I need to achieve: cross device, cross browsers high performance reaction (subsecond reactions) average nb of players per hour: up to 10K players per hour (quite high indeed but it’s because we aim at proving our case for the game to our business unit) So what I would like to know: 2D Tiled map: Do I need tiledmapeditor or can I enable me split the screen like here ? should I use canvas or plain html/css could be sufficient for my need? do I need a game engine/framework such as melon.js or crafty./js ? (even if the game play is extremely basic, I do need mouse and touché device support, mouse emulations on touch devices…) or ca I easily/quickly do it without? for my constraints and targets, should I use CPU acceleration ? for my constraints and targets, should I use web workers ? for the database, for a massively real time game should I avoid to put the current locations of player in MySQL as i feel it might slow me down. What kind of DB should I implement ? Thanks for your help !

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• HOW TO: Change Internet Expenses Cost Center Prompt

  - by rveliche

  The cost center segment on the General Information page in Oracle Internet Expenses derives its label from the Prompt entered on the KFF setup. Changing this is not possible with the simple personalization, the details below provide the instructions to change the Prompt. Create a custom class, I call it CustomHeaderKffCO.java in the package oracle.apps.ap.oie.entry.header.webui  (or any other). This class will have to extend from oracle.apps.ap.oie.entry.header.webui.HeaderKffCO. Add the following logic to your custom class. package oracle.apps.ap.oie.entry.header.webui; import oracle.apps.fnd.framework.webui.OAPageContext; import oracle.apps.fnd.framework.webui.beans.OAWebBean; import oracle.apps.fnd.framework.webui.beans.message.OAMessageLayoutBean; import oracle.apps.fnd.framework.webui.OAControllerImpl; public class CustomHeaderKffCO extends HeaderKffCO {   public void processRequest(OAPageContext pageContext, OAWebBean webBean)   {      super.processRequest(pageContext, webBean);     OAMessageLayoutBean layoutBean = (OAMessageLayoutBean) webBean.findChildRecursive("KffSEGMENT2MessageLayout");    if(layoutBean != null)   {     // You should use messages/lookups to avoid translation issues.     layoutBean.setLabel("Cost Center");   }   } } KffSEGMENT2MessageLayout is for illustration only, my Chart Of Accounts has SEGMENT2 as the cost center segment. Please change this to a segment being used eg.Segment6 should be KFFSEGMENT6MessageLayout Note that super.processRequest(pageContext, webBean); is a must and should always be the first statement. Once the class is compiled, copy the class to an appropriate directory, in my case I used $JAVA_TOP/oracle/apps/ap/oie/entry/header/webui. Navigate to the General Information page, click on "Personalize General Information Page".Click on Personalize icon next to Message Component Layout: (OIEGeneralInformationMsgCLayout)In the controller class section update the new controller at the appropriate levelIf the Link "Personalize General Information Page" is not visible on your instance, check your personalization profiles.

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• Setting the SlideShowExtender's Index

  - by Bunch

  The AJAX SlideShowExtender is pretty useful. It does what it says and works without much fuss. There was one trick I needed it to perform that I could not find natively within the control. That was to set the slide’s current index. With a little JavaScript however I could make the control do what I wanted. The example below assumes a few things. First you already have a SlideShowExtender setup and working (or see this post). Second this SlideShowExtender is on a page all by itself so the index to set the slide to is passed in the URL. The scenario I had was this SSE was showing full images, the index was passed from another page that had a SSE showing thumbnails. JavaScript in <head> <script type="text/javascript">      function pageLoad() {          var slider = $find("sse");          var photoIndex = GetQuerystring('Index', 0);          slider._currentIndex = photoIndex - 1;          slider._slides = '';          slider.setCurrentImage();      }      function GetQuerystring(key, default_) {          if (default_ == null) default_ = '0';          key = key.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");          var regex = new RegExp("[\\?&]" + key + "=([^&#]*)");          var qs = regex.exec(window.location.href);          if (qs == null)              return default_;          else              return qs[1];      } </script> The GetQuerystring function is what grabs the Index value I pass from the page with the thumbnails. It does not have anything else to do with setting the slide index. The code in the pageLoad function sets the index on the slide_currentIndex line. The slider.setCurrentImage() line does pretty much what it says. I added the slider._slider = ‘’ to avoid an error (not a show stopper just a bit annoying). Control in <body> <cc1:SlideShowExtender ID="ssePhotos" runat="server" TargetControlID="imgFull" AutoPlay="false"          PreviousButtonID="btnPrev" NextButtonID="btnNext" SlideShowServicePath="PlacePhotos.asmx"           SlideShowServiceMethod="GetPlaceFullPhotos" BehaviorID="sse" ImageDescriptionLabelID="lblPictureDescription"> </cc1:SlideShowExtender> The main property to set with the SSE is the BehaviorID. This is what a JavaScript function can use to find the control rather than the control’s ID value. Technorati Tags: AJAX,ASP.Net,JavaScript

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• Rolling With the Punches

  - by D'Arcy Lussier

  So I’ve been tweeting the last little while “Rolling with the punches” and I’ve had some people ask me what that meant. Whether you’re running a conference (like I am this week), or a project, or a birthday party for a 2 year old, you need to be ready to handle those things that are unexpected. Risk mitigation can only go so far and its at those times that you need to become resourceful. So let me tell you what the last few days have been like. Today is the first day of Prairie Dev Con Winnipeg, a conference that I run. On Friday I was informed that my keynote speaker had lost his voice, one of my speakers had a family emergency and had to back out, and I got a warning from another that he was travelling over the weekend and if there was a storm or something he may not be able to get back by Monday for his talk. A storm didn’t happen, but their car did break down and he was delayed. Finally, Saturday night I took my printing order to Staples. It was at 5 and they closed at 6, and I had a bunch of surveys to be printed and cut. The girl working said that she’d have it ready by the next day (Sunday). Her intent was to come in the next morning and finish the job. Unfortunately, she had to be hospitalized that night and never made it into work…and never informed anyone of the remaining work. They found out at 3pm when I came to pick it up and there was no way they’d be able to cut everything in time. So how did we roll with these punches? - Miguel, my keynote speaker, was a trooper and was able to do the keynote but asked that his session get moved from Monday to Tuesday. This is why I wait until the last day before printing out schedules, they can change up to the event and even later. - I was able to move some sessions around to accommodate my stranded speaker and fill the empty slot from the speaker that couldn’t make it. - Staples was able to get me half the cut surveys so I took those and my wife will pick up the rest today. I altered how we’d collect session surveys, and actually I think it’ll work better. So all of this is to say, plan but also plan for what you can’t plan for – there will be things that happen that blindside you, that you’re not sure how to handle or solve. Stop, take a deep breath, and don’t feel that you need to limit yourself to the boundaries that you initially set for yourself. Roll with the punch and learn from it so that you can avoid the blow next time. Now, back to the conference! D

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• Is it dangerous for me to give some of my Model classes Control-like methods?

  - by Pureferret

  In my personal project I have tried to stick to MVC, but I've also been made aware that sticking to MVC too tightly can be a bad thing as it makes writing awkward and forces the flow of the program in odd ways (i.e. some simple functions can be performed by something that normally wouldn't, and avoid MVC related overheads). So I'm beginning to feel justified in this compromise: I have some 'manager programs' that 'own' data and have some way to manipulate it, as such I think they'd count as both part of the model, and part of the control, and to me this feels more natural than keepingthem separate. For instance: One of my Managers is the PlayerCharacterManager that has these methods: void buySkill(PlayerCharacter playerCharacter, Skill skill); void changeName(); void changeRole(); void restatCharacter(); void addCharacterToGame(); void createNewCharacter(); PlayerCharacter getPlayerCharacter(); List<PlayerCharacter> getPlayersCharacter(Player player); List<PlayerCharacter> getAllCharacters(); I hope the mothod names are transparent enough that they don't all need explaining. I've called it a manager because it will help manage all of the PlayerCharacter 'model' objects the code creates, and create and keep a map of these. I may also get it to store other information in the future. I plan to have another two similar classes for this sort of control, but I will orchestrate when and how this happens, and what to do with the returned data via a pure controller class. This splitting up control between informed managers and the controller, as opposed to operating just through a controller seems like it will simplify my code and make it flow more. My question is, is this a dangerous choice, in terms of making the code harder to follow/test/fix? Is this somethign established as good or bad or neutral? I oculdn't find anything similar except the idea of Actors but that's not quite why I'm trying to do. Edit: Perhaps an example is needed; I'm using the Controller to update the view and access the data, so when I click the 'Add new character to a player button' it'll call methods in the controller that then go and tell the PlayerCharacterManager class to create a new character instance, it'll call the PlayerManager class to add that new character to the player-character map, and then it'll add this information to the database, and tell the view to update any GUIs effected. That is the sort of 'control sequence' I'm hoping to create with these manager classes.

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• Is there a factory pattern to prevent multiple instances for same object (instance that is Equal) good design?

  - by dsollen

  I have a number of objects storing state. There are essentially two types of fields. The ones that uniquely define what the object is (what node, what edge etc), and the others that store state describing how these things are connected (this node is connected to these edges, this edge is part of these paths) etc. My model is updating the state variables using package methods, so all these objects act as immutable to anyone not in Model scope. All Objects extend one base type. I've toyed with the idea of a Factory approach which accepts a Builder object and constructs the applicable object. However, if an instance of the object already exists (ie would return true if I created the object defined by the builder and passed it to the equal method for the existing instance) the factory returns the current object instead of creating a new instance. Because the Equal method would only compare what uniquely defines the type of object (this is node A to node B) but won't check the dynamic state stuff (node A is currently connected to nodes C and E) this would be a way of ensuring anyone that wants my Node A automatically knows its state connections. More importantly it would prevent aliasing nightmares of someone trying to pass an instance of node A with different state then the node A in my model has. I've never heard of this pattern before, and it's a bit odd. I would have to do some overriding of serialization methods to make it work (ensure that when I read in a serilized object I add it to my facotry list of known instances, and/or return an existing factory in its place), as well as using a weakHashMap as if it was a weakHashSet to know whether an instance exists without worrying about a quasi-memory leak occuring. I don't know if this is too confusing or prone to its own obscure bugs. One thing I know is that plugins interface with lowest level hardware. The plugins have to be able to return state that is different than my memory; to tell my memory when its own state is inconsistent. I believe this is possible despite their fetching objects that exist in my memory; we allow building of objects without checking their consistency with the model until the addToModel is called anyways; and the existing plugins design was written before all this extra state existed and worked fine without ever being aware of it. Should I just be using some other design to avoid this crazyness? (I have another question to that affect that I'm posting).

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• Best language on Linux to replace manual tasks that use SSH/Telnet? [on hold]

  - by Calab

  I've been tasked to create and maintain a web browser based interface to replace several of the manual tasks that we perform now. I currently have a "shakey" but working program written in Perl (2779 lines) that uses basic Expect coding, but it has some limitations that require a great deal of coding to get around. Because of this I am going to do a complete rewrite and want to do it "right" this time. My question is this... What would be the best language to use to create a web based interface to perform SSH/Telnet tasks that we would normally do manually? Keep in mind the following requirements: Runs on a CentOS Linux system v5.10 Http will be served by Apache2 This is an INTRANET site and only accessible within our organization. User load will be light. No more that 5 users accessing it at one time. perl 5.8.8, php 5.3.3, python 2.7.2 are available... Not sure what other languages to check for, or what modules might be installed in each language. The web interface will need to provide progress indicators and text output produced by the remote connection, in real time as it is generated. If we are running our process on multiple hosts, they should be in individual threads so that they can run side by side, not sequentially. I want the ability to "trap" on specific text generated by the remote host and display an alert to the user - such as when the remote host generates an error message. I would like to avoid as much client side scripting (javascript/vbscript) as I can. Most users will be on Windows PC's using Chrome or IE as a browser. Users will be downloading the resulting output so they can process it as they see fit. I currently have no experience with "Ajax" or the like. Most of my coding experience is old 6809 assembly, Visual Basic 6, and whatever I can cut/paste from online examples in various languages (hence my "shaky" Perl program) My coding environment is Eclipse for remote code editing, but I prefer stuff like UltraEdit if I can get a decent syntax file for the language I'm using. I do have su access on the server, but I'm not the only one using this server so I can't just upgrade/install blindly as I might impact other software currently running on the machine. One reason that I'm asking here, instead of searching (which I did) is that most replies were, "use language 'xyz', but you need to use an external SSH connection" - like I'm using Expect in my Perl script. Most also did not agree on what language that 'xyz' should be. ...so, after this long posting, can someone offer some advice?

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• is a factory pattern to prevent multuple instances for same object (instance that is Equal) good design?

  - by dsollen

  I have a number of objects storing state. There are essentially two types of fields. The ones that uniquly define what the object is (what node, what edge etc), and the oens that store state describing how these things are connected (this node is connected to these edges, this edge is part of these paths) etc. My model is updating the state variables using package methdos, so these objects all act as immutable to anyone not in Model scope. All Objects extend one base type. I've toyed with the idea of a Factory approch which accepts a Builder object and construct the applicable object. However, if an instance of the object already exists (ie would return true if I created the object defined by the builder and passed it to the equal method for the existing instance) the factory returns the current object instead of creating a new instance. Because the Equal method would only compare what uniquly defines the type of object (this is node A nto node B) but won't check the dynamic state stuff (node A is currently connected to nodes C and E) this would be a way of ensuring anyone that wants my Node A automatically knows it's state connections. More importantly it would prevent aliasing nightmares of someone trying to pass an instance of node A with different state then the node A in my model has. I've never heard of this pattern before, and it's a bit odd. I would have to do some overiding of serlization methods to make it work (ensure when I read in a serilized object I add it to my facotry list of known instances, and/or return an existing factory in it's place), as well as using a weakHashMap as if it was a weakHashSet to know rather an instance exists without worrying about a quasi-memory leak occuring. I don't know if this is too confusing or prone to it's own obscure bugs. One thing I know is that plugins interface with lowest level hardware. The plugins have to be able to return state taht is different then my memory; to tell my memory when it's own state is inconsistent. I believe this is possible despit their fetching objects that exist in my memory; we allow building of objects without checking their consistency with the model until the addToModel is called anyways; and the existing plugins design was written before all this extra state existed and worked fine without ever being aware of it. Should I just be using some other design to avoid this crazyness? (I have another question to that affect I'm posting).

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• High traffic chat - how to check if there is new message and show it for all users

  - by user2633999

  I already had question about this but obviously it was not accepted very well, apparently too long when it's actually more information so you could have given me better answer. Ok, I will be much clearer now. Best possible logic to develop scalable chat in terms of stability, storing/reading messages on chat, updating chat on new message for all users etc.? I have most of this developed, the logic I think I miss is -- check if there is new message and show it for all users. I have this implemented but it crashes the site due to its traffic of 300k-400k people, so that's my main question. The chat is PHP based and uses Pusher (www.pusher.com) for instant messaging but it lacks what I need because it's more like a websocket. I'm using hardcoded files to keep messages (want to avoid database as much as possible). It's a no extension type of file, I'm sure you know. I'm getting crash with $fp = fopen(..., "w"); // pretend ... is the path and filename fwrite($fp, $msg); //hardcode the message fclose($fp); where $msg is the message itself. I'm having 1 file per message. I show last 150 messages = 150 file accesses and reads, yeah it's too much I guess. I have better logic now which I'm pursuing and that is 1 file with last 50-100 messages at all time. Sure it should be much better. How does it crash, that's the trickiest part because everything seems ordinary, believe me it is difficult to determine what exactly crashes the site, but in like 5 minutes when I try to open the site it's gone, then I put the old content without chat and is back online again. I'm having jquery post every 1 second to check if there is new message. I'm using timestamp in a special file where I keep the time last message was sent and if ((time() - time in file) <= 2) = reload last 150 messages including the last one. Too much input/output, write/read or however to say it I think is what crashes the site.

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• Cocos2D - Detecting collision

  - by Grace

  I am a beginner in cocos2d and im facing a problem with detecting collision for my coins. Sometimes it works sometimes it doesn't. So basically, im creating a game which the user (ship) have to avoid the obstacles and collect coins on the way. The collision of the obstacle works well but not for the coins. I was thinking maybe the loops for creating many coins is the problem but im not sure. Can anyone help? My codes: - (void)update:(ccTime)dt{ double curTime = CACurrentMediaTime(); if (curTime > _nextBridgeSpawn) { float randSecs = [self randomValueBetween:3.0 andValue:5.0]; _nextBridgeSpawn = randSecs + curTime; float randX = [self randomValueBetween:50 andValue:500]; float randDuration = [self randomValueBetween:8.0 andValue:10.0]; CCSprite *bridge = [_bridge objectAtIndex:_nextBridge]; _nextBridge++; if (_nextBridge >= _bridge.count) _nextBridge = 0; [bridge stopAllActions]; bridge.position = ccp(winSize.width/2, winSize.height); bridge.visible = YES; [bridge runAction:[CCSequence actions: [CCMoveBy actionWithDuration:randDuration position:ccp(0, -winSize.height)], [CCCallFuncN actionWithTarget:self selector:@selector(setInvisible:)], nil]]; this is where i declare my coins (continued from the update method) int randCoin = [self randomValueBetween:0 andValue:5]; _coin = [[CCArray alloc] initWithCapacity:randCoin]; for(int i = 0; i < randCoin; ++i) { coin = [CCSprite spriteWithFile:@"coin.png"]; coin.visible = NO; [self addChild:coin]; [_coin addObject:coin]; } float randCoinX = [self randomValueBetween:winSize.width/5 andValue:winSize.width - (border.contentSize.width *2)]; float randCoinY = [self randomValueBetween:100 andValue:700]; float randCoinPlace = [self randomValueBetween:30 andValue:60]; for (int i = 0; i < _coin.count; ++i) { CCSprite *coin2 = [_coin objectAtIndex:i]; coin2.position = ccp(randCoinX, (bridge.position.y + randCoinY) + (randCoinPlace *i)); coin2.visible = YES; [coin2 runAction:[CCSequence actions: [CCMoveBy actionWithDuration:randDuration position:ccp(0, -winSize.height-2000)], [CCCallFuncN actionWithTarget:self selector:@selector(setInvisible:)], nil]]; } } this is to check for collision (also in the update method) for (CCSprite *bridge in _bridge) { if (!bridge.visible) continue; if (CGRectIntersectsRect(ship.boundingBox, bridge.boundingBox)){ bridge.visible = NO; [ship runAction:[CCBlink actionWithDuration:1.0 blinks:5]]; } } } //this is the collision for coins which only work at times for (CCSprite *coin2 in _coin) { if (!coin2.visible) continue; if (CGRectIntersectsRect(ship.boundingBox, coin2.boundingBox)) { NSLog(@"Coin collected"); coin2.visible = NO; } } } Thank you.

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• The term "interface" in C++

  - by Flexo

  Java makes a clear distinction between class and interface. (I believe C# does also, but I have no experience with it). When writing C++ however there is no language enforced distinction between class and interface. Consequently I've always viewed interface as a workaround for the lack of multiple inheritance in Java. Making such a distinction feels arbitrary and meaningless in C++. I've always tended to go with the "write things in the most obvious way" approach, so if in C++ I've got what might be called an interface in Java, e.g.: class Foo { public: virtual void doStuff() = 0; ~Foo() = 0; }; and I then decided that most implementers of Foo wanted to share some common functionality I would probably write: class Foo { public: virtual void doStuff() = 0; ~Foo() {} protected: // If it needs this to do its thing: int internalHelperThing(int); // Or if it doesn't need the this pointer: static int someOtherHelper(int); }; Which then makes this not an interface in the Java sense anymore. Instead C++ has two important concepts, related to the same underlying inheritance problem: virtual inhertiance Classes with no member variables can occupy no extra space when used as a base "Base class subobjects may have zero size" Reference Of those I try to avoid #1 wherever possible - it's rare to encounter a scenario where that genuinely is the "cleanest" design. #2 is however a subtle, but important difference between my understanding of the term "interface" and the C++ language features. As a result of this I currently (almost) never refer to things as "interfaces" in C++ and talk in terms of base classes and their sizes. I would say that in the context of C++ "interface" is a misnomer. It has come to my attention though that not many people make such a distinction. Do I stand to lose anything by allowing (e.g. protected) non-virtual functions to exist within an "interface" in C++? (My feeling is the exactly the opposite - a more natural location for shared code) Is the term "interface" meaningful in C++ - does it imply only pure virtual or would it be fair to call C++ classes with no member variables an interface still?

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• Application workflow

  - by manseuk

  I am in the planning process for a new application, the application will be written in PHP (using the Symfony 2 framework) but I'm not sure how relevant that is. The application will be browser based, although there will eventually be API access for other systems to interact with the data stored within the application, again probably not relavent at this point. The application manages SIM cards for lots of different providers - each SIM card belongs to a single provider but a single customer might have many SIM cards across many providers. The application allows the user to perform actions against the SIM card - for example Activate it, Barr it, Check on its status etc Some of the providers provide an API for doing this - so a single access point with multiple methods eg activateSIM, getStatus, barrSIM etc. The method names differ for each provider and some providers offer methods for extra functions that others don't. Some providers don't have APIs but do offer these methods by sending emails with attachments - the attachments are normally a CSV file that contains the SIM reference and action required - the email is processed by the provider and replied to once the action has been complete. To give you an example - the front end of my application will provide a customer with a list of SIM cards they own and give them access to the actions that are provided by the provider of each specific SIM card - some methods may require extra data which will either be stored in the backend or collected from the user frontend. Once the user has selected their action and added any required data I will handle the process in the backend and provide either instant feedback, in the case of the providers with APIs, or start the process off by sending an email and waiting for its reply before processing it and updating the backend so that next time the user checks the SIM card its status is correct (ie updated by a backend process). My reason for creating this question is because I'm stuck !! I'm confused about how to approach the actual workflow logic. I was thinking about creating a Provider Interface with the most common methods getStatus, activateSIM and barrSIM and then implementing that interface for each provider. So class Provider1 implements Provider - Then use a Factory to create the required class depending on user selected SIM card and invoking the method selected. This would work fine if all providers offered the same methods but they don't - there are a subset which are common but some providers offer extra methods - how can I implement that flexibly ? How can I deal with the processes where the workflow is different - ie some methods require and API call and value returned and some require an email to be sent and the next stage of the process doesn't start until the email reply is recieved ... Please help ! (I hope this is a readable question and that this is the correct place to be asking) Update I guess what I'm trying to avoid is a big if or switch / case statement - some design pattern that gives me a flexible approach to implementing this kind of fluid workflow .. anyone ?

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• Searching for Windows User SID's in C#

  - by Ubiquitous Che

  Context Context first - issues I'm trying to resolve are below. One of our clients has asked as to quote how long it would take for us to improve one of our applications. This application currently provides basic user authentication in the form of username/password combinations. This client would like the ability for their employees to log-in using the details of whatever Windows User account is currently logged in at the time of running the application. It's not a deal-breaker if I tell them know - but the client might be willing to pay the costs of development to add this feature to the application. It's worth looking into. Based on my hunting around, it seems like storing the user login details against Domain\Username will be problematic if those details are changed. But Windows User SID's aren't supposed to change at all. I've got the impression that it would be best to record Windows Users by SID - feel free to relieve me of that if I'm wrong. I've been having a fiddle with some Windows API calls. From within C#, grabbing the current user's SID is easy enough. I can already take any user's SID and process it using LookupAccountSid to get username and domain for display purposes. For the interested, my code for this is at the end of this post. That's just the tip of the iceberg, however. The two issues below are completely outside my experience. Not only do I not know how to implement them - I don't even known how to find out how to implement them, or what the pitfalls are on various systems. Any help getting myself aimed in the right direction would be very much appreciated. Issue 1) Getting hold of the local user at runtime is meaningless if that user hasn't been granted access to the application. We will need to add a new section to our application's 'administrator console' for adding Windows Users (or groups) and assigning within-app permissions against those users. Something like an 'Add Windows User Login' button that will raise a pop-up window that will allow the user to search for available Windows User accounts on the network (not just the local machine) to be added to the list of available application logins. If there's already a component in .NET or Windows that I can shanghai into doing this for me, it would make me a very happy man. Issue 2) I also want to know how to take a given Windows User SID and check it against a given Windows User Group (probably taken from a database). I'm not sure how to get started with this one either, though I expect it to be easier than the issue above. For the Interested [STAThread] static void Main(string[] args) { MessageBox.Show(WindowsUserManager.GetAccountNameFromSID(WindowsIdentity.GetCurrent().User.Value)); MessageBox.Show(WindowsUserManager.GetAccountNameFromSID("S-1-5-21-57989841-842925246-1957994488-1003")); } public static class WindowsUserManager { public static string GetAccountNameFromSID(string SID) { try { StringBuilder name = new StringBuilder(); uint cchName = (uint)name.Capacity; StringBuilder referencedDomainName = new StringBuilder(); uint cchReferencedDomainName = (uint)referencedDomainName.Capacity; WindowsUserManager.SID_NAME_USE sidUse; int err = (int)ESystemError.ERROR_SUCCESS; if (!WindowsUserManager.LookupAccountSid(null, SID, name, ref cchName, referencedDomainName, ref cchReferencedDomainName, out sidUse)) { err = Marshal.GetLastWin32Error(); if (err == (int)ESystemError.ERROR_INSUFFICIENT_BUFFER) { name.EnsureCapacity((int)cchName); referencedDomainName.EnsureCapacity((int)cchReferencedDomainName); err = WindowsUserManager.LookupAccountSid(null, SID, name, ref cchName, referencedDomainName, ref cchReferencedDomainName, out sidUse) ? (int)ESystemError.ERROR_SUCCESS : Marshal.GetLastWin32Error(); } } if (err != (int)ESystemError.ERROR_SUCCESS) throw new ApplicationException(String.Format("Could not retrieve acount name from SID. {0}", SystemExceptionManager.GetDescription(err))); return String.Format(@"{0}\{1}", referencedDomainName.ToString(), name.ToString()); } catch (Exception ex) { if (ex is ApplicationException) throw ex; throw new ApplicationException("Could not retrieve acount name from SID", ex); } } private enum SID_NAME_USE { SidTypeUser = 1, SidTypeGroup, SidTypeDomain, SidTypeAlias, SidTypeWellKnownGroup, SidTypeDeletedAccount, SidTypeInvalid, SidTypeUnknown, SidTypeComputer } [DllImport("advapi32.dll", EntryPoint = "GetLengthSid", CharSet = CharSet.Auto)] private static extern int GetLengthSid(IntPtr pSID); [DllImport("advapi32.dll", SetLastError = true)] private static extern bool ConvertStringSidToSid( string StringSid, out IntPtr ptrSid); [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern bool LookupAccountSid( string lpSystemName, [MarshalAs(UnmanagedType.LPArray)] byte[] Sid, StringBuilder lpName, ref uint cchName, StringBuilder ReferencedDomainName, ref uint cchReferencedDomainName, out SID_NAME_USE peUse); private static bool LookupAccountSid( string lpSystemName, string stringSid, StringBuilder lpName, ref uint cchName, StringBuilder ReferencedDomainName, ref uint cchReferencedDomainName, out SID_NAME_USE peUse) { byte[] SID = null; IntPtr SID_ptr = IntPtr.Zero; try { WindowsUserManager.ConvertStringSidToSid(stringSid, out SID_ptr); int err = SID_ptr == IntPtr.Zero ? Marshal.GetLastWin32Error() : (int)ESystemError.ERROR_SUCCESS; if (SID_ptr == IntPtr.Zero || err != (int)ESystemError.ERROR_SUCCESS) throw new ApplicationException(String.Format("'{0}' could not be converted to a SID byte array. {1}", stringSid, SystemExceptionManager.GetDescription(err))); int size = (int)GetLengthSid(SID_ptr); SID = new byte[size]; Marshal.Copy(SID_ptr, SID, 0, size); } catch (Exception ex) { if (ex is ApplicationException) throw ex; throw new ApplicationException(String.Format("'{0}' could not be converted to a SID byte array. {1}.", stringSid, ex.Message), ex); } finally { // Always want to release the SID_ptr (if it exists) to avoid memory leaks. if (SID_ptr != IntPtr.Zero) Marshal.FreeHGlobal(SID_ptr); } return WindowsUserManager.LookupAccountSid(lpSystemName, SID, lpName, ref cchName, ReferencedDomainName, ref cchReferencedDomainName, out peUse); } }

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• Signals and threads - good or bad design decision?

  - by Jens

  I have to write a program that performs highly computationally intensive calculations. The program might run for several days. The calculation can be separated easily in different threads without the need of shared data. I want a GUI or a web service that informs me of the current status. My current design uses BOOST::signals2 and BOOST::thread. It compiles and so far works as expected. If a thread finished one iteration and new data is available it calls a signal which is connected to a slot in the GUI class. My question(s): Is this combination of signals and threads a wise idea? I another forum somebody advised someone else not to "go down this road". Are there potential deadly pitfalls nearby that I failed to see? Is my expectation realistic that it will be "easy" to use my GUI class to provide a web interface or a QT, a VTK or a whatever window? Is there a more clever alternative (like other boost libs) that I overlooked? following code compiles with g++ -Wall -o main -lboost_thread-mt <filename>.cpp code follows: #include <boost/signals2.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <iostream> #include <iterator> #include <string> using std::cout; using std::cerr; using std::string; /** * Called when a CalcThread finished a new bunch of data. */ boost::signals2::signal<void(string)> signal_new_data; /** * The whole data will be stored here. */ class DataCollector { typedef boost::mutex::scoped_lock scoped_lock; boost::mutex mutex; public: /** * Called by CalcThreads call the to store their data. */ void push(const string &s, const string &caller_name) { scoped_lock lock(mutex); _data.push_back(s); signal_new_data(caller_name); } /** * Output everything collected so far to std::out. */ void out() { typedef std::vector<string>::const_iterator iter; for (iter i = _data.begin(); i != _data.end(); ++i) cout << " " << *i << "\n"; } private: std::vector<string> _data; }; /** * Several of those can calculate stuff. * No data sharing needed. */ struct CalcThread { CalcThread(string name, DataCollector &datcol) : _name(name), _datcol(datcol) { } /** * Expensive algorithms will be implemented here. * @param num_results how many data sets are to be calculated by this thread. */ void operator()(int num_results) { for (int i = 1; i <= num_results; ++i) { std::stringstream s; s << "["; if (i == num_results) s << "LAST "; s << "DATA " << i << " from thread " << _name << "]"; _datcol.push(s.str(), _name); } } private: string _name; DataCollector &_datcol; }; /** * Maybe some VTK or QT or both will be used someday. */ class GuiClass { public: GuiClass(DataCollector &datcol) : _datcol(datcol) { } /** * If the GUI wants to present or at least count the data collected so far. * @param caller_name is the name of the thread whose data is new. */ void slot_data_changed(string caller_name) const { cout << "GuiClass knows: new data from " << caller_name << std::endl; } private: DataCollector & _datcol; }; int main() { DataCollector datcol; GuiClass mc(datcol); signal_new_data.connect(boost::bind(&GuiClass::slot_data_changed, &mc, _1)); CalcThread r1("A", datcol), r2("B", datcol), r3("C", datcol), r4("D", datcol), r5("E", datcol); boost::thread t1(r1, 3); boost::thread t2(r2, 1); boost::thread t3(r3, 2); boost::thread t4(r4, 2); boost::thread t5(r5, 3); t1.join(); t2.join(); t3.join(); t4.join(); t5.join(); datcol.out(); cout << "\nDone" << std::endl; return 0; }

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• Am I crazy? (How) should I create a jQuery content editor?

  - by Brendon Muir

  Ok, so I created a CMS mainly aimed at Primary Schools. It's getting fairly popular in New Zealand but the one thing I hate with a passion is the largely bad quality of in browser WYSIWYG editors. I've been using KTML (made by InterAKT which was purchased by Adobe a few years ago). In my opinion this editor does a lot of great things (image editing/management, thumbnailing and pretty good content editing). Unfortunately time has had its nasty way with this product and new browsers are beginning to break features and generally degrade the performance of this tool. It's also quite scary basing my livelihood on a defunct product! I've been hunting, in fact I regularly hunt around to see if anything has changed in the WYSIWYG arena. The closest thing I've seen that excites me is the WYSIHAT framework, but they've decided to ignore a pretty relevant editing paradigm which I'm going to outline below. This is the idea for my proposed editor, and I don't know of any existing products that can do this properly: Right, so the traditional model for editing let's say a Page in a CMS is to log into a 'back end' and click edit on the page. This will then load another screen with the editor in it and perhaps a few other fields. More advanced CMS's will maybe have several editing boxes that are for different portions of the page. Anyway, the big problem with this way of doing things is that the user is editing a document outside of the final context it will appear in. In the simplest terms, this means the page template. Many things can be wrong, e.g. the with of the editing area might be different to the width of the actual template area. The height is nearly always fixed because existing editors always seem to use IFRAMES for backward compatibility. And there are plenty of other beefs which I'm sure you're quite aware of if you're in this development area. Here's my editor utopia: You click 'Edit Page': The actual page (with its actual template) displays. Portions of the page have been marked as editable via a class name. You click on one of these areas (in my case it'd just be the big 'body' area in the middle of the template) and a editing bar drops down from the top of the screen with all your standard controls (bold, italic, insert image etc...). Iframes are never used, instead we rely on setting contentEditable to true on the DIV's in question. Firefox 2 and IE6 can go away, let's move on. You can edit the page knowing exactly how it will look when you save it. Because all the styles for this template are loaded, your headings will look correct, everything will be just dandy. Is this such a radical concept? Why are we still content with TinyMCE and that other editor that is too embarrassing to use because it sounds like a swear word!? Let's face the facts: I'm a JavaScript novice. I did once play around in this area using the Javascript Anthology from SitePoint as a guide. It was quite a cool learning experience, but they of course used the IFRAME to make their lives easier. I tried to go a different route and just use contentEditable and even tried to sidestep the native content editing routines (execCommand) and instead wrote my own. They kind of worked but there were always issues. Now we have jQuery, and a few libraries that abstract things like IE's lack of Range support. I'm wondering, am I crazy, or is it actually a good idea to try and build an editor around this editing paradigm using jQuery and relevant plugins to make the job easier? My actual questions: Where would you start? What plugins do you know of that would help the most? Is it worth it, or is there a magical project that already exists that I should join in on? What are the biggest hurdles to overcome in a project like this? Am I crazy? I hope this question has been posted on the right board. I figured it is a technical question as I'm wanting to know specific hurdles and pitfalls to watch out for and also if it is technically feasible with todays technology. Looking forward to hearing peoples thoughts and opinions.

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• Overly accessible and incredibly resource hungry relationships between business objects. How can I f

  - by Mike

  Hi, Firstly, This might seem like a long question. I don't think it is... The code is just an overview of what im currently doing. It doesn't feel right, so I am looking for constructive criticism and warnings for pitfalls and suggestions of what I can do. I have a database with business objects. I need to access properties of parent objects. I need to maintain some sort of state through business objects. If you look at the classes, I don't think that the access modifiers are right. I don't think its structured very well. Most of the relationships are modelled with public properties. SubAccount.Account.User.ID <-- all of those are public.. Is there a better way to model a relationship between classes than this so its not so "public"? The other part of this question is about resources: If I was to make a User.GetUserList() function that returns a List, and I had 9000 users, when I call the GetUsers method, it will make 9000 User objects and inside that it will make 9000 new AccountCollection objects. What can I do to make this project not so resource hungry? Please find the code below and rip it to shreds. public class User { public string ID {get;set;} public string FirstName {get; set;} public string LastName {get; set;} public string PhoneNo {get; set;} public AccountCollection accounts {get; set;} public User { accounts = new AccountCollection(this); } public static List<Users> GetUsers() { return Data.GetUsers(); } } public AccountCollection : IEnumerable<Account> { private User user; public AccountCollection(User user) { this.user = user; } public IEnumerable<Account> GetEnumerator() { return Data.GetAccounts(user); } } public class Account { public User User {get; set;} //This is public so that the subaccount can access its Account's User's ID public int ID; public string Name; public Account(User user) { this.user = user; } } public SubAccountCollection : IEnumerable<SubAccount> { public Account account {get; set;} public SubAccountCollection(Account account) { this.account = account; } public IEnumerable<SubAccount> GetEnumerator() { return Data.GetSubAccounts(account); } } public class SubAccount { public Account account {get; set;} //this is public so that my Data class can access the account, to get the account's user's ID. public SubAccount(Account account) { this.account = account; } public Report GenerateReport() { Data.GetReport(this); } } public static class Data { public static List<Account> GetSubAccounts(Account account) { using (var dc = new databaseDataContext()) { List<SubAccount> query = (from a in dc.Accounts where a.UserID == account.User.ID //this is getting the account's user's ID select new SubAccount(account) { ID = a.ID, Name = a.Name, }).ToList(); } } public static List<Account> GetAccounts(User user) { using (var dc = new databaseDataContext()) { List<Account> query = (from a in dc.Accounts where a.UserID == User.ID //this is getting the user's ID select new Account(user) { ID = a.ID, Name = a.Name, }).ToList(); } } public static Report GetReport(SubAccount subAccount) { Report report = new Report(); //database access code here //need to get the user id of the subaccount's account for data querying. //i've got the subaccount, but how should i get the user id. //i would imagine something like this: int accountID = subAccount.Account.User.ID; //but this would require the subaccount's Account property to be public. //i do not want this to be accessible from my other project (UI). //reading up on internal seems to do the trick, but within my code it still feels //public. I could restrict the property to read, and only private set. return report; } public static List<User> GetUsers() { using (var dc = new databaseDataContext()) { var query = (from u in dc.Users select new User { ID = u.ID, FirstName = u.FirstName, LastName = u.LastName, PhoneNo = u.PhoneNo }).ToList(); return query; } } }

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• NTUSER.DAT and UsrClass.dat files building up by the thousands, why and can I delete?

  - by Anthony

  I've noticed that my web server, 2008 Xen VM, gradually loosing free space - more than I would of though from normal use and decided to investigate. There are two problem areas: *C:\Users\Administrator\ (6,755.0 MB)* with files: NTUSER.DAT{randomness}.TMContainer'0000 randomness'.regtrans-ms NTUSER.DAT{randomness}.TM.blf AND C:\Users\Administrator\AppData\Local\Microsoft\Windows\ (6,743.8 MB) with files UsrClass.dat{randomness}.TMContainer'0000 randomness'.regtrans-ms UsrClass.dat{randomness}.TM.blf From what I understand these are in-time backups of registry changes. If that is the case I cannot possibly understand why there would be 10000+ changes. (That's how many files there are per folder location, over 20,000 per folder in total.) The files are using almost 15GB of space and I want rid of them, I'm just wondering can I remove them. However, I need to understand why they are being created so I can avoid this in the future. Any ideas why there would be so many? Is there a way I can check to see what is making the modifications? Are they created with login attempts? Are they created in relation to every day Web Server use? etc. and so on

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