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  • Design Question - how do you break the dependency between classes using an interface?

    - by Seth Spearman
    Hello, I apologize in advance but this will be a long question. I'm stuck. I am trying to learn unit testing, C#, and design patterns - all at once. (Maybe that's my problem.) As such I am reading the Art of Unit Testing (Osherove), and Clean Code (Martin), and Head First Design Patterns (O'Reilly). I am just now beginning to understand delegates and events (which you would see if you were to troll my SO questions of recent). I still don't quite get lambdas. To contextualize all of this I have given myself a learning project I am calling goAlarms. I have an Alarm class with members you'd expect (NextAlarmTime, Name, AlarmGroup, Event Trigger etc.) I wanted the "Timer" of the alarm to be extensible so I created an IAlarmScheduler interface as follows... public interface AlarmScheduler { Dictionary<string,Alarm> AlarmList { get; } void Startup(); void Shutdown(); void AddTrigger(string triggerName, string groupName, Alarm alarm); void RemoveTrigger(string triggerName); void PauseTrigger(string triggerName); void ResumeTrigger(string triggerName); void PauseTriggerGroup(string groupName); void ResumeTriggerGroup(string groupName); void SetSnoozeTrigger(string triggerName, int duration); void SetNextOccurrence (string triggerName, DateTime nextOccurrence); } This IAlarmScheduler interface define a component that will RAISE an alarm (Trigger) which will bubble up to my Alarm class and raise the Trigger Event of the alarm itself. It is essentially the "Timer" component. I have found that the Quartz.net component is perfectly suited for this so I have created a QuartzAlarmScheduler class which implements IAlarmScheduler. All that is fine. My problem is that the Alarm class is abstract and I want to create a lot of different KINDS of alarm. For example, I already have a Heartbeat alarm (triggered every (int) interval of minutes), AppointmentAlarm (triggered on set date and time), Daily Alarm (triggered every day at X) and perhaps others. And Quartz.NET is perfectly suited to handle this. My problem is a design problem. I want to be able to instantiate an alarm of any kind without my Alarm class (or any derived classes) knowing anything about Quartz. The problem is that Quartz has awesome factories that return just the right setup for the Triggers that will be needed by my Alarm classes. So, for example, I can get a Quartz trigger by using TriggerUtils.MakeMinutelyTrigger to create a trigger for the heartbeat alarm described above. Or TriggerUtils.MakeDailyTrigger for the daily alarm. I guess I could sum it up this way. Indirectly or directly I want my alarm classes to be able to consume the TriggerUtils.Make* classes without knowing anything about them. I know that is a contradiction, but that is why I am asking the question. I thought about putting a delegate field into the alarm which would be assigned one of these Make method but by doing that I am creating a hard dependency between alarm and Quartz which I want to avoid for both unit testing purposes and design purposes. I thought of using a switch for the type in QuartzAlarmScheduler per here but I know it is bad design and I am trying to learn good design. If I may editorialize a bit. I've decided that coding (predefined) classes is easy. Design is HARD...in fact, really hard and I am really fighting feeling stupid right now. I guess I want to know if you really smart people took a while to really understand and master this stuff or should I feel stupid (as I do) because I haven't grasped it better in the couple of weeks/months I have been studying. You guys are awesome and thanks in advance for your answers. Seth

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  • Business rule validation of hierarchical list of objects ASP.NET MVC

    - by SergeanT
    I have a list of objects that are organized in a tree using a Depth property: public class Quota { [Range(0, int.MaxValue, ErrorMessage = "Please enter an amount above zero.")] public int Amount { get; set; } public int Depth { get; set; } [Required] [RegularExpression("^[a-zA-Z]+$")] public string Origin { get; set; } // ... another properties with validation attributes } For data example (amount - origin) 100 originA 200 originB 50 originC 150 originD the model data looks like: IList<Quota> model = new List<Quota>(); model.Add(new Quota{ Amount = 100, Depth = 0, Origin = "originA"); model.Add(new Quota{ Amount = 200, Depth = 0, Origin = "originB"); model.Add(new Quota{ Amount = 50, Depth = 1, Origin = "originC"); model.Add(new Quota{ Amount = 150, Depth = 1, Orinig = "originD"); Editing of the list Then I use Editing a variable length list, ASP.NET MVC 2-style to raise editing of the list. Controller actions QuotaController.cs: public class QuotaController : Controller { // // GET: /Quota/EditList public ActionResult EditList() { IList<Quota> model = // ... assigments as in example above; return View(viewModel); } // // POST: /Quota/EditList [HttpPost] public ActionResult EditList(IList<Quota> quotas) { if (ModelState.IsValid) { // ... save logic return RedirectToAction("Details"); } return View(quotas); // Redisplay the form with errors } // ... other controller actions } View EditList.aspx: <%@ Page Title="" Language="C#" ... Inherits="System.Web.Mvc.ViewPage<IList<Quota>>" %> ... <h2>Edit Quotas</h2> <%=Html.ValidationSummary("Fix errors:") %> <% using (Html.BeginForm()) { foreach (var quota in Model) { Html.RenderPartial("QuotaEditorRow", quota); } %> <% } %> ... Partial View QuotaEditorRow.ascx: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Quota>" %> <div class="quotas" style="margin-left: <%=Model.Depth*45 %>px"> <% using (Html.BeginCollectionItem("Quotas")) { %> <%=Html.HiddenFor(m=>m.Id) %> <%=Html.HiddenFor(m=>m.Depth) %> <%=Html.TextBoxFor(m=>m.Amount, new {@class = "number", size = 5})%> <%=Html.ValidationMessageFor(m=>m.Amount) %> Origin: <%=Html.TextBoxFor(m=>m.Origin)%> <%=Html.ValidationMessageFor(m=>m.Origin) %> ... <% } %> </div> Business rule validation How do I implement validation of business rule: Amount of quota and sum of amounts of nested quotas should equal (e.a. 200 = 50 + 150 in example)? I want to appropriate inputs Html.TextBoxFor(m=>m.Amount) be highlighted red if the rule is broken for it. In example if user enters not 200, but 201 - it should be red on submit. Using sever validation only. Thanks a lot for any advise.

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  • Resizing Images In a Table Using JavaScript

    - by Abluescarab
    Hey, all. I apologize beforehand if none of this makes sense, or if I sound incompetent... I've been making webpages for a while, but don't know any JavaScript. I am trying to make a webpage for a friend, and he requested if I could write some code to resize the images in the page based on the user's screen resolution. I did some research on this question, and it's kind of similar to this, this, and this. Unfortunately, those articles didn't answer my question entirely because none of the methods described worked. Right now, I have a three-column webpage with 10 images in a table in the left sidebar, and when I use percentages for their sizes, they don't resize right between monitors. As such, I'm trying to write a JavaScript function that changes their sizes after detecting the screen resolution. The code is stripped from my post if I put it all, so I'll just say that each image links to a website and uses a separate image to change color when you hover over it. Would I have to address both images to change their sizes correctly? I use a JavaScript function to switch between them. Anyway, I tried both methods in this article and neither worked for me. If it helps, I'm using Google Chrome, but I'm trying to make this page as cross-browser as possible. Here's the code I have so far in my JavaScript function: function resizeImages() { var w = window.width; var h = window.height; var yuk = document.getElementById('yuk').style; var wb = document.getElementById('wb').style; var tf = document.getElementById('tf').style; var lh = document.getElementById('lh').style; var ko = document.getElementById('ko').style; var gz = document.getElementById('gz').style; var fb = document.getElementById('fb').style; var eg = document.getElementById('eg').style; var dl = document.getElementById('dl').style; var da = document.getElementById('da').style; if (w = "800" && h = "600") { } else if (w = "1024" && h = "768") { } else if (w = "1152" && h = "864") { } else if (w = "1280" && h = "720") { } else if (w = "1280" && h = "768") { } else if (w = "1280" && h = "800") { } else if (w = "1280" && h = "960") { } else if (w = "1280" && h = "1024") { } } Yeah, I don't have much in it because I don't know if I'm doing it right yet. Is this a way I can detect the "width" and "height" properties of a window? The "yuk", "wb", etcetera are the images I'm trying to change the size of. To sum it up: I want to resize images based on screen resolution using JavaScript, but my research attempts have been... futile. I'm sorry if that was long-winded, but thanks ahead of time!

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  • evaluating cost/benefits of using extension methods in C# => 3.0

    - by BillW
    Hi, In what circumstances (usage scenarios) would you choose to write an extension rather than sub-classing an object ? < full disclosure : I am not an MS employee; I do not know Mitsu Furota personally; I do know the author of the open-source Componax library mentioned here, but I have no business dealings with him whatsoever; I am not creating, or planning to create any commercial product using extensions : in sum : this post is from pure intellectal curiousity related to my trying to (continually) become aware of "best practices" I find the idea of extension methods "cool," and obviously you can do "far-out" things with them as in the many examples you can in Mitsu Furota's (MS) blog postslink text. A personal friend wrote the open-source Componax librarylink text, and there's some remarkable facilities in there; but he is in complete command of his small company with total control over code guidelines, and every line of code "passes through his hands." While this is speculation on my part : I think/guess other issues might come into play in a medium-to-large software team situation re use of Extensions. Looking at MS's guidelines at link text, you find : In general, you will probably be calling extension methods far more often than implementing your own. ... In general, we recommend that you implement extension methods sparingly and only when you have to. Whenever possible, client code that must extend an existing type should do so by creating a new type derived from the existing type. For more information, see Inheritance (C# Programming Guide). ... When the compiler encounters a method invocation, it first looks for a match in the type's instance methods. If no match is found, it will search for any extension methods that are defined for the type, and bind to the first extension method that it finds. And at Ms's link text : Extension methods present no specific security vulnerabilities. They can never be used to impersonate existing methods on a type, because all name collisions are resolved in favor of the instance or static method defined by the type itself. Extension methods cannot access any private data in the extended class. Factors that seem obvious to me would include : I assume you would not write an extension unless you expected it be used very generally and very frequently. On the other hand : couldn't you say the same thing about sub-classing ? Knowing we can compile them into a seperate dll, and add the compiled dll, and reference it, and then use the extensions : is "cool," but does that "balance out" the cost inherent in the compiler first having to check to see if instance methods are defined as described above. Or the cost, in case of a "name clash," of using the Static invocation methods to make sure your extension is invoked rather than the instance definition ? How frequent use of Extensions would affect run-time performance or memory use : I have no idea. So, I'd appreciate your thoughts, or knowing about how/when you do, or don't do, use Extensions, compared to sub-classing. thanks, Bill

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  • (Ordered) Set Partitions in fixed-size Blocks

    - by Eugen
    Here is a function I would like to write but am unable to do so. Even if you don't / can't give a solution I would be grateful for tips. For example, I know that there is a correlation between the ordered represantions of the sum of an integer and ordered set partitions but that alone does not help me in finding the solution. So here is the description of the function I need: The Task Create an efficient* function List<int[]> createOrderedPartitions(int n_1, int n_2,..., int n_k) that returns a list of arrays of all set partions of the set {0,...,n_1+n_2+...+n_k-1} in number of arguments blocks of size (in this order) n_1,n_2,...,n_k (e.g. n_1=2, n_2=1, n_3=1 -> ({0,1},{3},{2}),...). Here is a usage example: int[] partition = createOrderedPartitions(2,1,1).get(0); partition[0]; // -> 0 partition[1]; // -> 1 partition[2]; // -> 3 partition[3]; // -> 2 Note that the number of elements in the list is (n_1+n_2+...+n_n choose n_1) * (n_2+n_3+...+n_n choose n_2) * ... * (n_k choose n_k). Also, createOrderedPartitions(1,1,1) would create the permutations of {0,1,2} and thus there would be 3! = 6 elements in the list. * by efficient I mean that you should not initially create a bigger list like all partitions and then filter out results. You should do it directly. Extra Requirements If an argument is 0 treat it as if it was not there, e.g. createOrderedPartitions(2,0,1,1) should yield the same result as createOrderedPartitions(2,1,1). But at least one argument must not be 0. Of course all arguments must be = 0. Remarks The provided pseudo code is quasi Java but the language of the solution doesn't matter. In fact, as long as the solution is fairly general and can be reproduced in other languages it is ideal. Actually, even better would be a return type of List<Tuple<Set>> (e.g. when creating such a function in Python). However, then the arguments wich have a value of 0 must not be ignored. createOrderedPartitions(2,0,2) would then create [({0,1},{},{2,3}),({0,2},{},{1,3}),({0,3},{},{1,2}),({1,2},{},{0,3}),...] Background I need this function to make my mastermind-variation bot more efficient and most of all the code more "beautiful". Take a look at the filterCandidates function in my source code. There are unnecessary / duplicate queries because I'm simply using permutations instead of specifically ordered partitions. Also, I'm just interested in how to write this function. My ideas for (ugly) "solutions" Create the powerset of {0,...,n_1+...+n_k}, filter out the subsets of size n_1, n_2 etc. and create the cartesian product of the n subsets. However this won't actually work because there would be duplicates, e.g. ({1,2},{1})... First choose n_1 of x = {0,...,n_1+n_2+...+n_n-1} and put them in the first set. Then choose n_2 of x without the n_1 chosen elements beforehand and so on. You then get for example ({0,2},{},{1,3},{4}). Of course, every possible combination must be created so ({0,4},{},{1,3},{2}), too, and so on. Seems rather hard to implement but might be possible. Research I guess this goes in the direction I want however I don't see how I can utilize it for my specific scenario. http://rosettacode.org/wiki/Combinations

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  • Need .Net method to compute a Google Pagerank request checksum.

    - by Steve K
    The company I work for is currently developing a SEO tool which needs to include a domain or url Pagerank. It is possible to retrieve such data directly from Google by sending a request to the url called by the Google ToolBar. On of the parameters send to that url is a checksum of the domain whose pagerank is being requested. I have found multiple .Net methods for calculating that check sum; however, every one randomly returns corrupt values every so often. I can only handle errors to a certain point before my final data set becomes useless. I know that there are countless tools out there, from browser plugins to desktop applications, that can process page rank, so it can't be impossible. My question, then, is two fold: 1) Any anyone heard of the problem I am having? (specifically in .Net) If so, how can it (or has it) be resolved? 2) Is there a better source for retrieving Pagerank data? Below is the Url and checksum code I have been using. "http://toolbarqueries.google.com/search?client=navclient-auto&ie=UTF-8&oe=UTF-8&features=Rank:&q=info:" & strUrl & "ch=" & strCheckSum where: strUrl = the url being queried strCheckSum = CheckHash(GetHash(url)) (see code below) Any help would be greatly appreciated. ''' <summary> ''' Returns a hash-string from the site's URL ''' </summary> ''' <param name="_SiteURL">full URL as indexed by Google</param> ''' <returns>HASH for site as a string</returns> Private Shared Function GetHash(ByVal _SiteURL As String) As String Try Dim _Check1 As Long = StrToNum(_SiteURL, 5381, 33) Dim _Check2 As Long = StrToNum(_SiteURL, 0, 65599) _Check1 >>= 2 _Check1 = ((_Check1 >> 4) And 67108800) Or (_Check1 And 63) _Check1 = ((_Check1 >> 4) And 4193280) Or (_Check1 And 1023) _Check1 = ((_Check1 >> 4) And 245760) Or (_Check1 And 16383) Dim T1 As Long = ((((_Check1 And 960) << 4) Or (_Check1 And 60)) << 2) Or (_Check2 And 3855) Dim T2 As Long = ((((_Check1 And 4294950912) << 4) Or (_Check1 And 15360)) << 10) Or (_Check2 And 252641280) Return Convert.ToString(T1 Or T2) Catch Return "0" End Try End Function ''' <summary> ''' Checks the HASH-string returned and adds check numbers as necessary ''' </summary> ''' <param name="_HashNum">generated HASH-string</param> ''' <returns>modified HASH-string</returns> Private Shared Function CheckHash(ByVal _HashNum As String) As String Try Dim _CheckByte As Long = 0 Dim _Flag As Long = 0 Dim _tempI As Long = Convert.ToInt64(_HashNum) If _tempI < 0 Then _tempI = _tempI * (-1) End If Dim _Hash As String = _tempI.ToString() Dim _Length As Integer = _Hash.Length For x As Integer = _Length - 1 To 0 Step -1 Dim _quick As Char = _Hash(x) Dim _Re As Long = Convert.ToInt64(_quick.ToString()) If 1 = (_Flag Mod 2) Then _Re += _Re _Re = CLng(((_Re \ 10) + (_Re Mod 10))) End If _CheckByte += _Re _Flag += 1 Next _CheckByte = _CheckByte Mod 10 If 0 <> _CheckByte Then _CheckByte = 10 - _CheckByte If 1 = (_Flag Mod 2) Then If 1 = (_CheckByte Mod 2) Then _CheckByte >>= 1 End If End If End If If _Hash.Length = 9 Then _CheckByte += 5 End If Return "7" + _CheckByte.ToString() + _Hash Catch Return "0" End Try End Function ''' <summary> ''' Converts the string (site URL) into numbers for the HASH ''' </summary> ''' <param name="_str">Site URL as passed by GetHash()</param> ''' <param name="_Chk">Necessary passed value</param> ''' <param name="_Magic">Necessary passed value</param> ''' <returns>Long Integer manipulation of string passed</returns> Private Shared Function StrToNum(ByVal _str As String, ByVal _Chk As Long, ByVal _Magic As Long) As Long Try Dim _Int64Unit As Long = Convert.ToInt64(Math.Pow(2, 32)) Dim _StrLen As Integer = _str.Length For x As Integer = 0 To _StrLen - 1 _Chk *= _Magic If _Chk >= _Int64Unit Then _Chk = (_Chk - (_Int64Unit * Convert.ToInt64(_Chk \ _Int64Unit))) _Chk = IIf((_Chk < -2147483648), (_Chk + _Int64Unit), _Chk) End If _Chk += CLng(Asc(_str(x))) Next Catch End Try Return _Chk End Function

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  • Adding view cart function

    - by user228390
    Hey guys need some help in adding a view cart button but I'm stuck not sure how to code it. any help? The way I have coded it is that when a user clicks 'add item' they will get a alert box with info about the total price but I want that to appear in the HTML file but only once I have clicked on 'view cart' and I need it to be in a table format with info about the name, sum, price of the items and total. any ideas how I can do this? here is my javascript var f,d,str,items,qnts,price,bag,total; function cart(){ f=document.forms[0]; d=f.getElementsByTagName('div'); var items=[];var qnts=[];price=[];bag=[] for(i=0,e=0;i<d.length;i++){ items[i]=d[i].getElementsByTagName('b')[0].innerHTML; qnts[i]=d[i].getElementsByTagName('select')[0].value; str=d[i].getElementsByTagName('p')[1].innerHTML; priceStart(str,i); if(qnts[i]!=0){bag.push(new Array()); ib=bag[bag.length-1]; ib.push(items[i]);ib.push(qnts[i]);ib.push(price[i]);ib.push(qnts[i]*price[i]);} } if(bag.length>0){ total=bag[0][3]; if(bag.length>1){for(t=1;t<bag.length;t++){total+=bag[t][3]}} alert(bag.join('\n')+'\n----------------\ntotal='+total) } } function priceStart(str,inx){for(j=0;j<str.length;j++){if(str.charAt(j)!=' ' && !isNaN(str.charAt(j))){priceEnd(j,str,inx);return }}} function priceEnd(j,str,inx){for(k=str.length;k>j;k--){if(str.charAt(k)!=' ' && !isNaN(str.charAt(k))){price[inx]=str.substring(j,k);return }}} and my HTML <script type="text/javascript" src="cart.js" /> </script> <link rel="stylesheet" type="text/css" href="shopping_cart.css" /> <title> A title </title> </head> <body> <form name="form1" method="post" action="data.php" > <div id="product1"> <p id="title1"><b>Star Wars Tie Interceptor</b></p> <img src="images/DS.jpg" /> <p id="price1">Price £39.99</p> <p><b>Qty</b></p> <select name="qty"> <option value="0">0</option> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> </select> <input type="button" value="Add to cart" onclick="cart()" /> </div>

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  • How to best propagate changes upwards a hierarchical structure for binding?

    - by H.B.
    If i have a folder-like structure that uses the composite design pattern and i bind the root folder to a TreeView. It would be quite useful if i can display certain properties that are being accumulated from the folder's contents. The question is, how do i best inform the folder that changes occurred in a child-element so that the accumulative properties get updated? The context in which i need this is a small RSS-FeedReader i am trying to make. This are the most important objects and aspects of my model: Composite interface: public interface IFeedComposite : INotifyPropertyChanged { string Title { get; set; } int UnreadFeedItemsCount { get; } ObservableCollection<FeedItem> FeedItems { get; } } FeedComposite (aka Folder) public class FeedComposite : BindableObject, IFeedComposite { private string title = ""; public string Title { get { return title; } set { title = value; NotifyPropertyChanged("Title"); } } private ObservableCollection<IFeedComposite> children = new ObservableCollection<IFeedComposite>(); public ObservableCollection<IFeedComposite> Children { get { return children; } set { children.Clear(); foreach (IFeedComposite item in value) { children.Add(item); } NotifyPropertyChanged("Children"); } } public FeedComposite() { } public FeedComposite(string title) { Title = title; } public ObservableCollection<FeedItem> FeedItems { get { ObservableCollection<FeedItem> feedItems = new ObservableCollection<FeedItem>(); foreach (IFeedComposite child in Children) { foreach (FeedItem item in child.FeedItems) { feedItems.Add(item); } } return feedItems; } } public int UnreadFeedItemsCount { get { return (from i in FeedItems where i.IsUnread select i).Count(); } } Feed: public class Feed : BindableObject, IFeedComposite { private string url = ""; public string Url { get { return url; } set { url = value; NotifyPropertyChanged("Url"); } } ... private ObservableCollection<FeedItem> feedItems = new ObservableCollection<FeedItem>(); public ObservableCollection<FeedItem> FeedItems { get { return feedItems; } set { feedItems.Clear(); foreach (FeedItem item in value) { AddFeedItem(item); } NotifyPropertyChanged("Items"); } } public int UnreadFeedItemsCount { get { return (from i in FeedItems where i.IsUnread select i).Count(); } } public Feed() { } public Feed(string url) { Url = url; } Ok, so here's the thing, if i bind a TextBlock.Text to the UnreadFeedItemsCount there won't be simple notifications when an item is marked unread, so one of my approaches has been to handle the PropertyChanged event of every FeedItem and if the IsUnread-Property is changed i have my Feed make a notification that the property UnreadFeedItemsCount has been changed. With this approach i also need to handle all PropertyChanged events of all Feeds and FeedComposites in Children of FeedComposite, from the sound of it, it should be obvious that this is not such a very good idea, you need to be very careful that items never get added or removed to any collection without having attached the PropertyChanged event handler first and things like that. Also: What do i do with the CollectionChanged-Events which necessarily also cause a change in the sum of the unread items count? Sounds like more event handling fun. It is such a mess, it would be great if anyone has an elegant solution to this since i don't want the feed-reader to end up as awful as my first attempt years ago when i didn't even know about DataBinding...

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  • System.Threading.Timer Doesn't Trigger my TimerCallBack Delegate

    - by Tom Kong
    Hi, I am writing my first Windows Service using C# and I am having some trouble with my Timer class. When the service is started, it runs as expected but the code will not execute again (I want it to run every minute) Please take a quick look at the attached source and let me know if you see any obvious mistakes! TIA using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Diagnostics; using System.Linq; using System.ServiceProcess; using System.Text; using System.Threading; using System.IO; namespace CXO001 { public partial class Service1 : ServiceBase { public Service1() { InitializeComponent(); } /* * Aim: To calculate and update the Occupancy values for the different Sites * * Method: Retrieve data every minute, updating a public value which can be polled */ protected override void OnStart(string[] args) { Daemon(); } public void Daemon() { TimerCallback tcb = new TimerCallback(On_Tick); TimeSpan duetime = new TimeSpan(0, 0, 1); TimeSpan interval = new TimeSpan(0, 1, 0); Timer querytimer = new Timer(tcb, null, duetime, interval); } protected override void OnStop() { } static int[] floorplanids = new int[] { 115, 114, 107, 108 }; public static List<Record> Records = new List<Record>(); static bool firstrun = true; public static void On_Tick(object timercallback) { //Update occupancy data for the last minute //Save a copy of the public values to HDD with a timestamp string starttime; if (Records.Count > 0) { starttime = Records.Last().TS; firstrun = false; } else { starttime = DateTime.Today.AddHours(7).ToString(); firstrun = true; } DateTime endtime = DateTime.Now; GetData(starttime, endtime); } public static void GetData(string starttime, DateTime endtime) { string connstr = "Data Source = 192.168.1.123; Initial Catalog = Brickstream_OPS; User Id = Brickstream; Password = bstas;"; DataSet resultds = new DataSet(); //Get the occupancy for each Zone foreach (int zone in floorplanids) { SQL s = new SQL(); string querystr = "SELECT SUM(DIRECTIONAL_METRIC.NUM_TO_ENTER - DIRECTIONAL_METRIC.NUM_TO_EXIT) AS 'Occupancy' FROM REPORT_OBJECT INNER JOIN REPORT_OBJ_METRIC ON REPORT_OBJECT.REPORT_OBJ_ID = REPORT_OBJ_METRIC.REPORT_OBJECT_ID INNER JOIN DIRECTIONAL_METRIC ON REPORT_OBJ_METRIC.REP_OBJ_METRIC_ID = DIRECTIONAL_METRIC.REP_OBJ_METRIC_ID WHERE (REPORT_OBJ_METRIC.M_START_TIME BETWEEN '" + starttime + "' AND '" + endtime.ToString() + "') AND (REPORT_OBJECT.FLOORPLAN_ID = '" + zone + "');"; resultds = s.Go(querystr, connstr, zone.ToString(), resultds); } List<Record> result = new List<Record>(); int c = 0; foreach (DataTable dt in resultds.Tables) { Record r = new Record(); r.TS = DateTime.Now.ToString(); r.Zone = dt.TableName; if (!firstrun) { r.Occupancy = (dt.Rows[0].Field<int>("Occupancy")) + (Records[c].Occupancy); } else { r.Occupancy = dt.Rows[0].Field<int>("Occupancy"); } result.Add(r); c++; } Records = result; MrWriter(); } public static void MrWriter() { StringBuilder output = new StringBuilder("Time,Zone,Occupancy\n"); foreach (Record r in Records) { output.Append(r.TS); output.Append(","); output.Append(r.Zone); output.Append(","); output.Append(r.Occupancy.ToString()); output.Append("\n"); } output.Append(firstrun.ToString()); output.Append(DateTime.Now.ToFileTime()); string filePath = @"C:\temp\CXO.csv"; File.WriteAllText(filePath, output.ToString()); } } }

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  • Java ME scorecard with vector and multiple input fields/screens

    - by proximity
    I have made a scorecard with 5 holes, for each a input field (shots), and a image is shown. The input should be saved into a vector and shown on each hole, eg. hole 2: enter shots, underneath it "total shots: 4" (if you have made 4 shots on hole 1). In the end I would need a sum up of all shots, eg. Hole 1: 4 Hole 2: 3 Hole 3: 2 ... Total: 17 Could someone please help me with this task? { f = new Form("Scorecard"); d = Display.getDisplay(this); mTextField = new TextField("Shots:", "", 2, TextField.NUMERIC); f.append(mTextField); mStatus = new StringItem("Hole 1:", "Par 3, 480m"); f.append(mStatus); try { Image j = Image.createImage("/hole1.png"); ImageItem ii = new ImageItem("", j, 3, "Hole 1"); f.append(ii); } catch (java.io.IOException ioe) {} catch (Exception e) {} f.addCommand(mBackCommand); f.addCommand(mNextCommand); f.addCommand(mExitCommand); f.setCommandListener(this); Display.getDisplay(this).setCurrent(f); } public void startApp() { mBackCommand = new Command("Back", Command.BACK, 0); mNextCommand = new Command("Next", Command.OK, 1); mExitCommand = new Command("Exit", Command.EXIT, 2); } public void pauseApp() { } public void destroyApp(boolean unconditional) { } public void commandAction(Command c, Displayable d) { if (c == mExitCommand) { destroyApp(true); notifyDestroyed(); } else if ( c == mNextCommand) { // -> go to next hole input! save the mTextField input into a vector. } } } ------------------------------ Full code --------------------------------- import java.util.; import javax.microedition.midlet.; import javax.microedition.lcdui.*; public class ScorerMIDlet extends MIDlet implements CommandListener { private Command mExitCommand, mBackCommand, mNextCommand; private Display d; private Form f; private TextField mTextField; private Alert a; private StringItem mHole1; private int b; // repeat holeForm for all five holes and add the input into a vector or array. Display the values in the end after asking for todays date and put todays date in top of the list. Make it possible to go back in the form, eg. hole 3 - hole 2 - hole 1 public void holeForm(int b) { f = new Form("Scorecard"); d = Display.getDisplay(this); mTextField = new TextField("Shots:", "", 2, TextField.NUMERIC); f.append(mTextField); mHole1 = new StringItem("Hole 1:", "Par 5, 480m"); f.append(mHole1); try { Image j = Image.createImage("/hole1.png"); ImageItem ii = new ImageItem("", j, 3, "Hole 1"); f.append(ii); } catch (java.io.IOException ioe) {} catch (Exception e) {} // Set date&time in the end long now = System.currentTimeMillis(); DateField df = new DateField("Playing date:", DateField.DATE_TIME); df.setDate(new Date(now)); f.append(df); f.addCommand(mBackCommand); f.addCommand(mNextCommand); f.addCommand(mExitCommand); f.setCommandListener(this); Display.getDisplay(this).setCurrent(f); } public void startApp() { mBackCommand = new Command("Back", Command.BACK, 0); mNextCommand = new Command("OK-Next", Command.OK, 1); mExitCommand = new Command("Exit", Command.EXIT, 2); b = 0; holeForm(b); } public void pauseApp() {} public void destroyApp(boolean unconditional) {} public void commandAction(Command c, Displayable d) { if (c == mExitCommand) { destroyApp(true); notifyDestroyed(); } else if ( c == mNextCommand) { holeForm(b); } } }

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  • WP7 listbox binding not working properly

    - by Marco
    A noob error for sure (I started yesterday afternoon developing in WP7), but I'm wasting a lot time on it. I post my class and a little part of my code: public class ChronoLaps : INotifyPropertyChanged { private ObservableCollection<ChronoLap> laps = null; public int CurrentLap { get { return lap; } set { if (value == lap) return; // Some code here .... ChronoLap newlap = new ChronoLap() { // Some code here ... }; Laps.Insert(0, newlap); lap = value; NotifyPropertyChanged("CurrentLap"); NotifyPropertyChanged("Laps"); } } public ObservableCollection<ChronoLap> Laps { get { return laps; } set { if (value == laps) return; laps = value; if (laps != null) { laps.CollectionChanged += delegate { MeanTime = Laps.Sum(p => p.Time.TotalMilliseconds) / (Laps.Count * 1000); NotifyPropertyChanged("MeanTime"); }; } NotifyPropertyChanged("Laps"); } } } MainPage.xaml.cs public partial class MainPage : PhoneApplicationPage { public ChronoLaps History { get; private set; } private void butStart_Click(object sender, EventArgs e) { History = new ChronoLaps(); // History.Laps.Add(new ChronoLap() { Distance = 0 }); LayoutRoot.DataContext = History; } } MainPage.xaml <phone:PhoneApplicationPage> <Grid x:Name="LayoutRoot" Background="Transparent"> <Grid Grid.Row="2"> <ScrollViewer Margin="-5,13,3,36" Height="758"> <ListBox Name="lbHistory" ItemContainerStyle="{StaticResource ListBoxStyle}" ItemsSource="{Binding Laps}" HorizontalAlignment="Left" Margin="5,25,0,0" VerticalAlignment="Top" Width="444"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Lap}" Width="40" /> <TextBlock Text="{Binding Time}" Width="140" /> <TextBlock Text="{Binding TotalTime}" Width="140" /> <TextBlock Text="{Binding Distance}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </ScrollViewer> </Grid> </Grid> </phone:PhoneApplicationPage> Problem is that when I add one or more items to History.Laps collection, my listbox is not refreshed and these items don't appear. But if I remove comment on // History.Laps.Add(new ChronoLap()... line, this item appear and so every other inserted later. More: if I remove that comment and then write History.Laps.Clear() (before or after setting binding) binding is not working anymore. It's like it gets crazy if collection is empty. I really don't understand the reason... UPDATE AND SOLUTION: If i move History = new ChronoLaps(); LayoutRoot.DataContext = History; from butStart_Click to public MainPage() everything works as expected. Can someone explain me the reason?

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  • xsl:variable does not return a node-set in XSLT 2.0?

    - by Henry
    Hi all, I'm trying to get a node-set from a xsl variable for calculating. But my code only work with Opera, with other browsers, I keep getting the error. Please help me fix to run with all browser. Thanks in advance. Here are the xslt code: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:fn="http://www.w3.org/2005/xpath-functions"> <xsl:output method="html"/> <xsl:variable name="multipleSet"> <xsl:for-each select="myNums/numSet"> <xsl:element name="multiple"><xsl:value-of select="num1 * num2"/></xsl:element> </xsl:for-each> </xsl:variable> <xsl:template match="/"> <table border="1"> <tr> <th>Num 1</th> <th>Num 2</th> <th>Multiple</th> </tr> <xsl:for-each select="myNums/numSet"> <tr> <td><xsl:value-of select="num1"/></td> <td><xsl:value-of select="num2"/></td> <td><xsl:value-of select="num1 * num2"/></td> </tr> </xsl:for-each> <tr> <th colspan="2" align="right">Total:</th> <td><xsl:value-of select="sum($multipleSet/multiple)"/> </td> </tr> </table> </xsl:template> </xsl:stylesheet> And the xml: <?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/xsl" href="test.xsl"?> <myNums> <numSet> <num1>5</num1> <num2>5</num2> </numSet> <numSet> <num1>10</num1> <num2>5</num2> </numSet> <numSet> <num1>15</num1> <num2>20</num2> </numSet> </myNums>

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  • Normalizing a table

    - by Alex
    I have a legacy table, which I can't change. The values in it can be modified from legacy application (application also can't be changed). Due to a lot of access to the table from new application (new requirement), I'd like to create a temporary table, which would hopefully speed up the queries. The actual requirement, is to calculate number of business days from X to Y. For example, give me all business days from Jan 1'st 2001 until Dec 24'th 2004. The table is used to mark which days are off, as different companies may have different days off - it isn't just Saturday + Sunday) The temporary table would be created from a .NET program, each time user enters the screen for this query (user may run query multiple times, with different values, table is created once), so I'd like it to be as fast as possible. Approach below runs in under a second, but I only tested it with a small dataset, and still it takes probably close to half a second, which isn't great for UI - even though it's just the overhead for first query. The legacy table looks like this: CREATE TABLE [business_days]( [country_code] [char](3) , [state_code] [varchar](4) , [calendar_year] [int] , [calendar_month] [varchar](31) , [calendar_month2] [varchar](31) , [calendar_month3] [varchar](31) , [calendar_month4] [varchar](31) , [calendar_month5] [varchar](31) , [calendar_month6] [varchar](31) , [calendar_month7] [varchar](31) , [calendar_month8] [varchar](31) , [calendar_month9] [varchar](31) , [calendar_month10] [varchar](31) , [calendar_month11] [varchar](31) , [calendar_month12] [varchar](31) , misc. ) Each month has 31 characters, and any day off (Saturday + Sunday + holiday) is marked with X. Each half day is marked with an 'H'. For example, if a month starts on a Thursday, than it will look like (Thursday+Friday workdays, Saturday+Sunday marked with X): ' XX XX ..' I'd like the new table to look like so: create table #Temp (country varchar(3), state varchar(4), date datetime, hours int) And I'd like to only have rows for days which are off (marked with X or H from previous query) What I ended up doing, so far is this: Create a temporary-intermediate table, that looks like this: create table #Temp_2 (country_code varchar(3), state_code varchar(4), calendar_year int, calendar_month varchar(31), month_code int) To populate it, I have a union which basically unions calendar_month, calendar_month2, calendar_month3, etc. Than I have a loop which loops through all the rows in #Temp_2, after each row is processed, it is removed from #Temp_2. To process the row there is a loop from 1 to 31, and substring(calendar_month, counter, 1) is checked for either X or H, in which case there is an insert into #Temp table. [edit added code] Declare @country_code char(3) Declare @state_code varchar(4) Declare @calendar_year int Declare @calendar_month varchar(31) Declare @month_code int Declare @calendar_date datetime Declare @day_code int WHILE EXISTS(SELECT * From #Temp_2) -- where processed = 0) BEGIN Select Top 1 @country_code = t2.country_code, @state_code = t2.state_code, @calendar_year = t2.calendar_year, @calendar_month = t2.calendar_month, @month_code = t2.month_code From #Temp_2 t2 -- where processed = 0 set @day_code = 1 while @day_code <= 31 begin if substring(@calendar_month, @day_code, 1) = 'X' begin set @calendar_date = convert(datetime, (cast(@month_code as varchar) + '/' + cast(@day_code as varchar) + '/' + cast(@calendar_year as varchar))) insert into #Temp (country, state, date, hours) values (@country_code, @state_code, @calendar_date, 8) end if substring(@calendar_month, @day_code, 1) = 'H' begin set @calendar_date = convert(datetime, (cast(@month_code as varchar) + '/' + cast(@day_code as varchar) + '/' + cast(@calendar_year as varchar))) insert into #Temp (country, state, date, hours) values (@country_code, @state_code, @calendar_date, 4) end set @day_code = @day_code + 1 end delete from #Temp_2 where @country_code = country_code AND @state_code = state_code AND @calendar_year = calendar_year AND @calendar_month = calendar_month AND @month_code = month_code --update #Temp_2 set processed = 1 where @country_code = country_code AND @state_code = state_code AND @calendar_year = calendar_year AND @calendar_month = calendar_month AND @month_code = month_code END I am not an expert in SQL, so I'd like to get some input on my approach, and maybe even a much better approach suggestion. After having the temp table, I'm planning to do (dates would be coming from a table): select cast(convert(datetime, ('01/31/2012'), 101) -convert(datetime, ('01/17/2012'), 101) as int) - ((select sum(hours) from #Temp where date between convert(datetime, ('01/17/2012'), 101) and convert(datetime, ('01/31/2012'), 101)) / 8) Besides the solution of normalizing the table, the other solution I implemented for now, is a function which does all this logic of getting the business days by scanning the current table. It runs pretty fast, but I'm hesitant to call a function, if I can instead add a simpler query to get result. (I'm currently trying this on MSSQL, but I would need to do same for Sybase ASE and Oracle)

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  • Not sure I am using inheritance/polymorphism issue?

    - by planker1010
    So for this assignment I have to create a car class(parent) and a certifiedpreowned (child) and I need to have the parent class have a method to check if it is still under warranty. *checkWarrantyStatus(). that method calls the boolean isCoveredUnderWarranty() to veryify if the car still has warranty. My issue is in the certifiedpreowned class I have to call the isCoveredUnderWarranty() as well to see if it is covered under the extended warranty and then have it be called via the checkWarrantyStatus() in the car method. I hope this makes sense. So to sum it up I need to in the child class have it check the isCoveredUnderWarranty with extended warranty info. Then it has to move to the parent class so it can be called via checkWarrantyStatus. Here is my code, I have 1 error. public class Car { public int year; public String make; public String model; public int currentMiles; public int warrantyMiles; public int warrantyYears; int currentYear =java.util.Calendar.getInstance().get(java.util.Calendar.YEAR); /** construct car object with specific parameters*/ public Car (int y, String m, String mod, int mi){ this.year = y; this.make = m; this.model = mod; this.currentMiles = mi; } public int getWarrantyMiles() { return warrantyMiles; } public void setWarrantyMiles(int warrantyMiles) { this.warrantyMiles = warrantyMiles; } public int getWarrantyYears() { return warrantyYears; } public void setWarrantyYears(int warrantyYears) { this.warrantyYears = warrantyYears; } public boolean isCoveredUnderWarranty(){ if (currentMiles < warrantyMiles){ if (currentYear < (year+ warrantyYears)) return true; } return false; } public void checkWarrantyStatus(){ if (isCoveredUnderWarranty()){ System.out.println("Your car " + year+ " " + make+ " "+ model+ " With "+ currentMiles +" is still covered under warranty"); } else System.out.println("Your car " + year+ " " + make+ " "+ model+ " With "+ currentMiles +" is out of warranty"); } } public class CertifiedPreOwnCar extends Car{ public CertifiedPreOwnCar(int y, String m, String mod, int mi) { super(mi, m, mod, y); } public int extendedWarrantyYears; public int extendedWarrantyMiles; public int getExtendedWarrantyYears() { return extendedWarrantyYears; } public void setExtendedWarrantyYears(int extendedWarrantyYears) { this.extendedWarrantyYears = extendedWarrantyYears; } public int getExtendedWarrantyMiles() { return extendedWarrantyMiles; } public void setExtendedWarrantyMiles(int extendedWarrantyMiles) { this.extendedWarrantyMiles = extendedWarrantyMiles; } public boolean isCoveredUnderWarranty() { if (currentMiles < extendedWarrantyMiles){ if (currentYear < (year+ extendedWarrantyYears)) return true; } return false; } } public class TestCar { public static void main(String[] args) { Car car1 = new Car(2014, "Honda", "Civic", 255); car1.setWarrantyMiles(60000); car1.setWarrantyYears(5); car1.checkWarrantyStatus(); Car car2 = new Car(2000, "Ferrari", "F355", 8500); car2.setWarrantyMiles(20000); car2.setWarrantyYears(7); car2.checkWarrantyStatus(); CertifiedPreOwnCar car3 = new CertifiedPreOwnCar(2000, "Honda", "Accord", 65000); car3.setWarrantyYears(3); car3.setWarrantyMiles(30000); car3.setExtendedWarrantyMiles(100000); car3.setExtendedWarrantyYears(7); car3.checkWarrantyStatus(); } }

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  • Generating strongly biased radom numbers for tests

    - by nobody
    I want to run tests with randomized inputs and need to generate 'sensible' random numbers, that is, numbers that match good enough to pass the tested function's preconditions, but hopefully wreak havoc deeper inside its code. math.random() (I'm using Lua) produces uniformly distributed random numbers. Scaling these up will give far more big numbers than small numbers, and there will be very few integers. I would like to skew the random numbers (or generate new ones using the old function as a randomness source) in a way that strongly favors 'simple' numbers, but will still cover the whole range, I.e. extending up to positive/negative infinity (or ±1e309 for double). This means: numbers up to, say, ten should be most common, integers should be more common than fractions, numbers ending in 0.5 should be the most common fractions, followed by 0.25 and 0.75; then 0.125, and so on. A different description: Fix a base probability x such that probabilities will sum to one and define the probability of a number n as xk where k is the generation in which n is constructed as a surreal number1. That assigns x to 0, x2 to -1 and +1, x3 to -2, -1/2, +1/2 and +2, and so on. This gives a nice description of something close to what I want (it skews a bit too much), but is near-unusable for computing random numbers. The resulting distribution is nowhere continuous (it's fractal!), I'm not sure how to determine the base probability x (I think for infinite precision it would be zero), and computing numbers based on this by iteration is awfully slow (spending near-infinite time to construct large numbers). Does anyone know of a simple approximation that, given a uniformly distributed randomness source, produces random numbers very roughly distributed as described above? I would like to run thousands of randomized tests, quantity/speed is more important than quality. Still, better numbers mean less inputs get rejected. Lua has a JIT, so performance can't be reasonably predicted. Jumps based on randomness will break every prediction, and many calls to math.random() will be slow, too. This means a closed formula will be better than an iterative or recursive one. 1 Wikipedia has an article on surreal numbers, with a nice picture. A surreal number is a pair of two surreal numbers, i.e. x := {n|m}, and its value is the number in the middle of the pair, i.e. (for finite numbers) {n|m} = (n+m)/2 (as rational). If one side of the pair is empty, that's interpreted as increment (or decrement, if right is empty) by one. If both sides are empty, that's zero. Initially, there are no numbers, so the only number one can build is 0 := { | }. In generation two one can build numbers {0| } =: 1 and { |0} =: -1, in three we get {1| } =: 2, {|1} =: -2, {0|1} =: 1/2 and {-1|0} =: -1/2 (plus some more complex representations of known numbers, e.g. {-1|1} ? 0). Note that e.g. 1/3 is never generated by finite numbers because it is an infinite fraction – the same goes for floats, 1/3 is never represented exactly.

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  • Referencing variables in a structure / C++

    - by user1628622
    Below, I provided a minimal example of code I created. I managed to get this code working, but I'm not sure if the practice being employed is sound. In essence, what I am trying to do is have the 'Parameter' class reference select elements in the 'States' class, so variables in States can be changed via Parameters. Questions I have: is the approach taken OK? If not, is there a better way to achieve what I am aiming for? Example code: struct VAR_TYPE{ public: bool is_fixed; // If is_fixed = true, then variable is a parameter double value; // Numerical value std::string name; // Description of variable (to identify it by name) }; struct NODE{ public: VAR_TYPE X, Y, Z; /* VAR_TYPE is a structure of primitive types */ }; class States{ private: std::vector <NODE_ptr> node; // shared ptr to struct NODE std::vector <PROP_DICTIONARY_ptr> property; // CAN NOT be part of Parameter std::vector <ELEMENT_ptr> element; // CAN NOT be part of Parameter public: /* ect */ void set_X_reference ( Parameter &T , int i ) { T.push_var( &node[i]->X ); } void set_Y_reference ( Parameter &T , int i ) { T.push_var( &node[i]->Y ); } void set_Z_reference ( Parameter &T , int i ) { T.push_var( &node[i]->Z ); } bool get_node_bool_X( int i ) { return node[i]->X.is_fixed; } // repeat for Y and Z }; class Parameter{ private: std::vector <VAR_TYPE*> var; public: /* ect */ }; int main(){ States S; Parameter P; /* Here I initialize and set S, and do other stuff */ // Now I assign components in States to Parameters for(int n=0 ; n<S.size_of_nodes() ; n++ ){ if ( S.get_node_bool_X(n)==true ){ S.set_X_reference ( P , n ); }; // repeat if statement for Y and Z }; /* Now P points selected to data in S, and I can * modify the contents of S through P */ return 0; }; Update The reason this issue cropped up is I am working with Fortran legacy code. To sum up this Fotran code - it's a numerical simulation of a flight vehicle. This code has a fairly rigid procedural framework one must work within, which comes with a pre-defined list of allowable Fortran types. The Fortran glue code can create an instance of a C++ object (in actuality, a reference from the perspective of Fortran), but is not aware what is contained in it (other means are used to extract C++ data into Fortran). The problem that I encountered is when a C++ module is dynamically linked to the Fortran glue code, C++ objects have to be initialized each instance the C++ code is called. This happens by virtue of how the Fortran template is defined. To avoid this cycle of re-initializing objects, I plan to use 'State' as a container class. The Fortran code allows a 'State' object, which has an arbitrary definition; but I plan to use it to harness all relevant information about the model. The idea is to use the Parameters class (which is exposed and updated by the Fortran code) to update variables in States.

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  • SQL Server and Hyper-V Dynamic Memory - Part 1

    - by SQLOS Team
    SQL and Dynamic Memory Blog Post Series   Hyper-V Dynamic Memory is a new feature in Windows Server 2008 R2 SP1 that allows the memory assigned to guest virtual machines to vary according to demand. Using this feature with SQL Server is supported, but how well does it work in an environment where available memory can vary dynamically, especially since SQL Server likes memory, and is not very eager to let go of it? The next three posts will look at this question in detail. In Part 1 Serdar Sutay, a program manager in the Windows Hyper-V team, introduces Dynamic Memory with an overview of the basic architecture, configuration and monitoring concepts. In subsequent parts we will look at SQL Server memory handling, and develop some guidelines on using SQL Server with Dynamic Memory.   Part 1: Dynamic Memory Introduction   In virtualized environments memory is often the bottleneck for reaching higher VM densities. In Windows Server 2008 R2 SP1 Hyper-V introduced a new feature “Dynamic Memory” to improve VM densities on Hyper-V hosts. Dynamic Memory increases the memory utilization in virtualized environments by enabling VM memory to be changed dynamically when the VM is running.   This brings up the question of how to utilize this feature with SQL Server VMs as SQL Server performance is very sensitive to the memory being used. In the next three posts we’ll discuss the internals of Dynamic Memory, SQL Server Memory Management and how to use Dynamic Memory with SQL Server VMs.   Memory Utilization Efficiency in Virtualized Environments   The primary reason memory is usually the bottleneck for higher VM densities is that users tend to be generous when assigning memory to their VMs. Here are some memory sizing practices we’ve heard from customers:   ·         I assign 4 GB of memory to my VMs. I don’t know if all of it is being used by the applications but no one complains. ·         I take the minimum system requirements and add 50% more. ·         I go with the recommendations provided by my software vendor.   In reality correctly sizing a virtual machine requires significant effort to monitor the memory usage of the applications. Since this is not done in most environments, VMs are usually over-provisioned in terms of memory. In other words, a SQL Server VM that is assigned 4 GB of memory may not need to use 4 GB.   How does Dynamic Memory help?   Dynamic Memory improves the memory utilization by removing the requirement to determine the memory need for an application. Hyper-V determines the memory needed by applications in the VM by evaluating the memory usage information in the guest with Dynamic Memory. VMs can start with a small amount of memory and they can be assigned more memory dynamically based on the workload of applications running inside.   Overview of Dynamic Memory Concepts   ·         Startup Memory: Startup Memory is the starting amount of memory when Dynamic Memory is enabled for a VM. Dynamic Memory will make sure that this amount of memory is always assigned to the VMs by default.   ·         Maximum Memory: Maximum Memory specifies the maximum amount of memory that a VM can grow to with Dynamic Memory. ·         Memory Demand: Memory Demand is the amount determined by Dynamic Memory as the memory needed by the applications in the VM. In Windows Server 2008 R2 SP1, this is equal to the total amount of committed memory of the VM. ·         Memory Buffer: Memory Buffer is the amount of memory assigned to the VMs in addition to their memory demand to satisfy immediate memory requirements and file cache needs.   Once Dynamic Memory is enabled for a VM, it will start with the “Startup Memory”. After the boot process Dynamic Memory will determine the “Memory Demand” of the VM. Based on this memory demand it will determine the amount of “Memory Buffer” that needs to be assigned to the VM. Dynamic Memory will assign the total of “Memory Demand” and “Memory Buffer” to the VM as long as this value is less than “Maximum Memory” and as long as physical memory is available on the host.   What happens when there is not enough physical memory available on the host?   Once there is not enough physical memory on the host to satisfy VM needs, Dynamic Memory will assign less than needed amount of memory to the VMs based on their importance. A concept known as “Memory Weight” is used to determine how much VMs should be penalized based on their needed amount of memory. “Memory Weight” is a configuration setting on the VM. It can be configured to be higher for the VMs with high performance requirements. Under high memory pressure on the host, the “Memory Weight” of the VMs are evaluated in a relative manner and the VMs with lower relative “Memory Weight” will be penalized more than the ones with higher “Memory Weight”.   Dynamic Memory Configuration   Based on these concepts “Startup Memory”, “Maximum Memory”, “Memory Buffer” and “Memory Weight” can be configured as shown below in Windows Server 2008 R2 SP1 Hyper-V Manager. Memory Demand is automatically calculated by Dynamic Memory once VMs start running.     Dynamic Memory Monitoring    In Windows Server 2008 R2 SP1, Hyper-V Manager displays the memory status of VMs in the following three columns:         ·         Assigned Memory represents the current physical memory assigned to the VM. In regular conditions this will be equal to the sum of “Memory Demand” and “Memory Buffer” assigned to the VM. When there is not enough memory on the host, this value can go below the Memory Demand determined for the VM. ·         Memory Demand displays the current “Memory Demand” determined for the VM. ·         Memory Status displays the current memory status of the VM. This column can represent three values for a VM: o   OK: In this condition the VM is assigned the total of Memory Demand and Memory Buffer it needs. o   Low: In this condition the VM is assigned all the Memory Demand and a certain percentage of the Memory Buffer it needs. o   Warning: In this condition the VM is assigned a lower memory than its Memory Demand. When VMs are running in this condition, it’s likely that they will exhibit performance problems due to internal paging happening in the VM.    So far so good! But how does it work with SQL Server?   SQL Server is aggressive in terms of memory usage for good reasons. This raises the question: How do SQL Server and Dynamic Memory work together? To understand the full story, we’ll first need to understand how SQL Server Memory Management works. This will be covered in our second post in “SQL and Dynamic Memory” series. Meanwhile if you want to dive deeper into Dynamic Memory you can check the below posts from the Windows Virtualization Team Blog:   http://blogs.technet.com/virtualization/archive/2010/03/18/dynamic-memory-coming-to-hyper-v.aspx   http://blogs.technet.com/virtualization/archive/2010/03/25/dynamic-memory-coming-to-hyper-v-part-2.aspx   http://blogs.technet.com/virtualization/archive/2010/04/07/dynamic-memory-coming-to-hyper-v-part-3.aspx   http://blogs.technet.com/b/virtualization/archive/2010/04/21/dynamic-memory-coming-to-hyper-v-part-4.aspx   http://blogs.technet.com/b/virtualization/archive/2010/05/20/dynamic-memory-coming-to-hyper-v-part-5.aspx   http://blogs.technet.com/b/virtualization/archive/2010/07/12/dynamic-memory-coming-to-hyper-v-part-6.aspx   - Serdar Sutay   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • SQL Server and Hyper-V Dynamic Memory - Part 1

    - by SQLOS Team
    SQL and Dynamic Memory Blog Post Series   Hyper-V Dynamic Memory is a new feature in Windows Server 2008 R2 SP1 that allows the memory assigned to guest virtual machines to vary according to demand. Using this feature with SQL Server is supported, but how well does it work in an environment where available memory can vary dynamically, especially since SQL Server likes memory, and is not very eager to let go of it? The next three posts will look at this question in detail. In Part 1 Serdar Sutay, a program manager in the Windows Hyper-V team, introduces Dynamic Memory with an overview of the basic architecture, configuration and monitoring concepts. In subsequent parts we will look at SQL Server memory handling, and develop some guidelines on using SQL Server with Dynamic Memory.   Part 1: Dynamic Memory Introduction   In virtualized environments memory is often the bottleneck for reaching higher VM densities. In Windows Server 2008 R2 SP1 Hyper-V introduced a new feature “Dynamic Memory” to improve VM densities on Hyper-V hosts. Dynamic Memory increases the memory utilization in virtualized environments by enabling VM memory to be changed dynamically when the VM is running.   This brings up the question of how to utilize this feature with SQL Server VMs as SQL Server performance is very sensitive to the memory being used. In the next three posts we’ll discuss the internals of Dynamic Memory, SQL Server Memory Management and how to use Dynamic Memory with SQL Server VMs.   Memory Utilization Efficiency in Virtualized Environments   The primary reason memory is usually the bottleneck for higher VM densities is that users tend to be generous when assigning memory to their VMs. Here are some memory sizing practices we’ve heard from customers:   ·         I assign 4 GB of memory to my VMs. I don’t know if all of it is being used by the applications but no one complains. ·         I take the minimum system requirements and add 50% more. ·         I go with the recommendations provided by my software vendor.   In reality correctly sizing a virtual machine requires significant effort to monitor the memory usage of the applications. Since this is not done in most environments, VMs are usually over-provisioned in terms of memory. In other words, a SQL Server VM that is assigned 4 GB of memory may not need to use 4 GB.   How does Dynamic Memory help?   Dynamic Memory improves the memory utilization by removing the requirement to determine the memory need for an application. Hyper-V determines the memory needed by applications in the VM by evaluating the memory usage information in the guest with Dynamic Memory. VMs can start with a small amount of memory and they can be assigned more memory dynamically based on the workload of applications running inside.   Overview of Dynamic Memory Concepts   ·         Startup Memory: Startup Memory is the starting amount of memory when Dynamic Memory is enabled for a VM. Dynamic Memory will make sure that this amount of memory is always assigned to the VMs by default.   ·         Maximum Memory: Maximum Memory specifies the maximum amount of memory that a VM can grow to with Dynamic Memory. ·         Memory Demand: Memory Demand is the amount determined by Dynamic Memory as the memory needed by the applications in the VM. In Windows Server 2008 R2 SP1, this is equal to the total amount of committed memory of the VM. ·         Memory Buffer: Memory Buffer is the amount of memory assigned to the VMs in addition to their memory demand to satisfy immediate memory requirements and file cache needs.   Once Dynamic Memory is enabled for a VM, it will start with the “Startup Memory”. After the boot process Dynamic Memory will determine the “Memory Demand” of the VM. Based on this memory demand it will determine the amount of “Memory Buffer” that needs to be assigned to the VM. Dynamic Memory will assign the total of “Memory Demand” and “Memory Buffer” to the VM as long as this value is less than “Maximum Memory” and as long as physical memory is available on the host.   What happens when there is not enough physical memory available on the host?   Once there is not enough physical memory on the host to satisfy VM needs, Dynamic Memory will assign less than needed amount of memory to the VMs based on their importance. A concept known as “Memory Weight” is used to determine how much VMs should be penalized based on their needed amount of memory. “Memory Weight” is a configuration setting on the VM. It can be configured to be higher for the VMs with high performance requirements. Under high memory pressure on the host, the “Memory Weight” of the VMs are evaluated in a relative manner and the VMs with lower relative “Memory Weight” will be penalized more than the ones with higher “Memory Weight”.   Dynamic Memory Configuration   Based on these concepts “Startup Memory”, “Maximum Memory”, “Memory Buffer” and “Memory Weight” can be configured as shown below in Windows Server 2008 R2 SP1 Hyper-V Manager. Memory Demand is automatically calculated by Dynamic Memory once VMs start running.     Dynamic Memory Monitoring    In Windows Server 2008 R2 SP1, Hyper-V Manager displays the memory status of VMs in the following three columns:         ·         Assigned Memory represents the current physical memory assigned to the VM. In regular conditions this will be equal to the sum of “Memory Demand” and “Memory Buffer” assigned to the VM. When there is not enough memory on the host, this value can go below the Memory Demand determined for the VM. ·         Memory Demand displays the current “Memory Demand” determined for the VM. ·         Memory Status displays the current memory status of the VM. This column can represent three values for a VM: o   OK: In this condition the VM is assigned the total of Memory Demand and Memory Buffer it needs. o   Low: In this condition the VM is assigned all the Memory Demand and a certain percentage of the Memory Buffer it needs. o   Warning: In this condition the VM is assigned a lower memory than its Memory Demand. When VMs are running in this condition, it’s likely that they will exhibit performance problems due to internal paging happening in the VM.    So far so good! But how does it work with SQL Server?   SQL Server is aggressive in terms of memory usage for good reasons. This raises the question: How do SQL Server and Dynamic Memory work together? To understand the full story, we’ll first need to understand how SQL Server Memory Management works. This will be covered in our second post in “SQL and Dynamic Memory” series. Meanwhile if you want to dive deeper into Dynamic Memory you can check the below posts from the Windows Virtualization Team Blog:   http://blogs.technet.com/virtualization/archive/2010/03/18/dynamic-memory-coming-to-hyper-v.aspx   http://blogs.technet.com/virtualization/archive/2010/03/25/dynamic-memory-coming-to-hyper-v-part-2.aspx   http://blogs.technet.com/virtualization/archive/2010/04/07/dynamic-memory-coming-to-hyper-v-part-3.aspx   http://blogs.technet.com/b/virtualization/archive/2010/04/21/dynamic-memory-coming-to-hyper-v-part-4.aspx   http://blogs.technet.com/b/virtualization/archive/2010/05/20/dynamic-memory-coming-to-hyper-v-part-5.aspx   http://blogs.technet.com/b/virtualization/archive/2010/07/12/dynamic-memory-coming-to-hyper-v-part-6.aspx   - Serdar Sutay   Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • SQL SERVER – Guest Posts – Feodor Georgiev – The Context of Our Database Environment – Going Beyond the Internal SQL Server Waits – Wait Type – Day 21 of 28

    - by pinaldave
    This guest post is submitted by Feodor. Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. In this article Feodor explains the server-client-server process, and concentrated on the mutual waits between client and SQL Server. This is essential in grasping the concept of waits in a ‘global’ application plan. Recently I was asked to write a blog post about the wait statistics in SQL Server and since I had been thinking about writing it for quite some time now, here it is. It is a wide-spread idea that the wait statistics in SQL Server will tell you everything about your performance. Well, almost. Or should I say – barely. The reason for this is that SQL Server is always a part of a bigger system – there are always other players in the game: whether it is a client application, web service, any other kind of data import/export process and so on. In short, the SQL Server surroundings look like this: This means that SQL Server, aside from its internal waits, also depends on external waits and settings. As we can see in the picture above, SQL Server needs to have an interface in order to communicate with the surrounding clients over the network. For this communication, SQL Server uses protocol interfaces. I will not go into detail about which protocols are best, but you can read this article. Also, review the information about the TDS (Tabular data stream). As we all know, our system is only as fast as its slowest component. This means that when we look at our environment as a whole, the SQL Server might be a victim of external pressure, no matter how well we have tuned our database server performance. Let’s dive into an example: let’s say that we have a web server, hosting a web application which is using data from our SQL Server, hosted on another server. The network card of the web server for some reason is malfunctioning (think of a hardware failure, driver failure, or just improper setup) and does not send/receive data faster than 10Mbs. On the other end, our SQL Server will not be able to send/receive data at a faster rate either. This means that the application users will notify the support team and will say: “My data is coming very slow.” Now, let’s move on to a bit more exciting example: imagine that there is a similar setup as the example above – one web server and one database server, and the application is not using any stored procedure calls, but instead for every user request the application is sending 80kb query over the network to the SQL Server. (I really thought this does not happen in real life until I saw it one day.) So, what happens in this case? To make things worse, let’s say that the 80kb query text is submitted from the application to the SQL Server at least 100 times per minute, and as often as 300 times per minute in peak times. Here is what happens: in order for this query to reach the SQL Server, it will have to be broken into a of number network packets (according to the packet size settings) – and will travel over the network. On the other side, our SQL Server network card will receive the packets, will pass them to our network layer, the packets will get assembled, and eventually SQL Server will start processing the query – parsing, allegorizing, generating the query execution plan and so on. So far, we have already had a serious network overhead by waiting for the packets to reach our Database Engine. There will certainly be some processing overhead – until the database engine deals with the 80kb query and its 20 subqueries. The waits you see in the DMVs are actually collected from the point the query reaches the SQL Server and the packets are assembled. Let’s say that our query is processed and it finally returns 15000 rows. These rows have a certain size as well, depending on the data types returned. This means that the data will have converted to packages (depending on the network size package settings) and will have to reach the application server. There will also be waits, however, this time you will be able to see a wait type in the DMVs called ASYNC_NETWORK_IO. What this wait type indicates is that the client is not consuming the data fast enough and the network buffers are filling up. Recently Pinal Dave posted a blog on Client Statistics. What Client Statistics does is captures the physical flow characteristics of the query between the client(Management Studio, in this case) and the server and back to the client. As you see in the image, there are three categories: Query Profile Statistics, Network Statistics and Time Statistics. Number of server roundtrips–a roundtrip consists of a request sent to the server and a reply from the server to the client. For example, if your query has three select statements, and they are separated by ‘GO’ command, then there will be three different roundtrips. TDS Packets sent from the client – TDS (tabular data stream) is the language which SQL Server speaks, and in order for applications to communicate with SQL Server, they need to pack the requests in TDS packets. TDS Packets sent from the client is the number of packets sent from the client; in case the request is large, then it may need more buffers, and eventually might even need more server roundtrips. TDS packets received from server –is the TDS packets sent by the server to the client during the query execution. Bytes sent from client – is the volume of the data set to our SQL Server, measured in bytes; i.e. how big of a query we have sent to the SQL Server. This is why it is best to use stored procedures, since the reusable code (which already exists as an object in the SQL Server) will only be called as a name of procedure + parameters, and this will minimize the network pressure. Bytes received from server – is the amount of data the SQL Server has sent to the client, measured in bytes. Depending on the number of rows and the datatypes involved, this number will vary. But still, think about the network load when you request data from SQL Server. Client processing time – is the amount of time spent in milliseconds between the first received response packet and the last received response packet by the client. Wait time on server replies – is the time in milliseconds between the last request packet which left the client and the first response packet which came back from the server to the client. Total execution time – is the sum of client processing time and wait time on server replies (the SQL Server internal processing time) Here is an illustration of the Client-server communication model which should help you understand the mutual waits in a client-server environment. Keep in mind that a query with a large ‘wait time on server replies’ means the server took a long time to produce the very first row. This is usual on queries that have operators that need the entire sub-query to evaluate before they proceed (for example, sort and top operators). However, a query with a very short ‘wait time on server replies’ means that the query was able to return the first row fast. However a long ‘client processing time’ does not necessarily imply the client spent a lot of time processing and the server was blocked waiting on the client. It can simply mean that the server continued to return rows from the result and this is how long it took until the very last row was returned. The bottom line is that developers and DBAs should work together and think carefully of the resource utilization in the client-server environment. From experience I can say that so far I have seen only cases when the application developers and the Database developers are on their own and do not ask questions about the other party’s world. I would recommend using the Client Statistics tool during new development to track the performance of the queries, and also to find a synchronous way of utilizing resources between the client – server – client. Here is another example: think about similar setup as above, but add another server to the game. Let’s say that we keep our media on a separate server, and together with the data from our SQL Server we need to display some images on the webpage requested by our user. No matter how simple or complicated the logic to get the images is, if the images are 500kb each our users will get the page slowly and they will still think that there is something wrong with our data. Anyway, I don’t mean to get carried away too far from SQL Server. Instead, what I would like to say is that DBAs should also be aware of ‘the big picture’. I wrote a blog post a while back on this topic, and if you are interested, you can read it here about the big picture. And finally, here are some guidelines for monitoring the network performance and improving it: Run a trace and outline all queries that return more than 1000 rows (in Profiler you can actually filter and sort the captured trace by number of returned rows). This is not a set number; it is more of a guideline. The general thought is that no application user can consume that many rows at once. Ask yourself and your fellow-developers: ‘why?’. Monitor your network counters in Perfmon: Network Interface:Output queue length, Redirector:Network errors/sec, TCPv4: Segments retransmitted/sec and so on. Make sure to establish a good friendship with your network administrator (buy them coffee, for example J ) and get into a conversation about the network settings. Have them explain to you how the network cards are setup – are they standalone, are they ‘teamed’, what are the settings – full duplex and so on. Find some time to read a bit about networking. In this short blog post I hope I have turned your attention to ‘the big picture’ and the fact that there are other factors affecting our SQL Server, aside from its internal workings. As a further reading I would still highly recommend the Wait Stats series on this blog, also I would recommend you have the coffee break conversation with your network admin as soon as possible. This guest post is written by Feodor Georgiev. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL

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  • Queued Loadtest to remove Concurrency issues using Shared Data Service in OpenScript

    - by stefan.thieme(at)oracle.com
    Queued Processing to remove Concurrency issues in Loadtest ScriptsSome scripts act on information returned by the server, e.g. act on first item in the returned list of pending tasks/actions. This may lead to concurrency issues if the virtual users simulated in a load test scenario are not synchronized in some way.As the load test cases should be carried out in a comparable and straight forward manner simply cancel a transaction in case a collision occurs is clearly not an option. In case you increase the number of virtual users this approach would lead to a high number of requests for the early steps in your transaction (e.g. login, retrieve list of action points, assign an action point to the virtual user) but later steps would be rarely visited successfully or at all, depending on the application logic.A way to tackle this problem is to enqueue the virtual users in a Shared Data Service queue. Only the first virtual user in this queue will be allowed to carry out the critical steps (retrieve list of action points, assign an action point to the virtual user) in your transaction at any one time.Once a virtual user has passed the critical path it will dequeue himself from the head of the queue and continue with his actions. This does theoretically allow virtual users to run in parallel all steps of the transaction which are not part of the critical path.In practice it has been seen this is rarely the case, though it does not allow adding more than N users to perform a transaction without causing delays due to virtual users waiting in the queue. N being the time of the total transaction divided by the sum of the time of all critical steps in this transaction.While this problem can be circumvented by allowing multiple queues to act on individual segments of the list of actions, e.g. per country filter, ends with 0..9 filter, etc.This would require additional handling of these additional queues of slots for the virtual users at the head of the queue in order to maintain the mutually exclusive access to the first element in the list returned by the server at any one time of the load test. Such an improved handling of multiple queues and/or multiple slots is above the subject of this paper.Shared Data Services Pre-RequisitesStart WebLogic Server to host Shared Data ServicesYou will have to make sure that your WebLogic server is installed and started. Shared Data Services may not work if you installed only the minimal installation package for OpenScript. If however you installed the default package including OLT and OTM, you may follow the instructions below to start and verify WebLogic installation.To start the WebLogic Server deployed underneath of Oracle Load Testing and/or Oracle Test Manager you can go to your Start menu, Oracle Application Testing Suite and select the Restart Oracle Application Testing Suite Application Service entry from the Tools submenu.To verify the service has been started you can run the Microsoft Management Console for Services by Selecting Run from the Start Menu and entering services.msc. Look for the entry that reads Oracle Application Testing Suite Application Service, once it has changed it status from Starting to Started you can proceed to verify the login. Please note that this may take several minutes, I would say up to 10 minutes depending on the strength of your CPU horse-power.Verify WebLogic Server user credentialsYou will have to make sure that your WebLogic Server is installed and started. Next open the Oracle WebLogic Server Adminstration Console on http://localhost:8088/console.It may take a while until the application is deployed and started. It may display the following until the Administration Console has been deployed on the fly.Afterwards you can login using the username oats and the password that you selected during install time for your Application Testing Suite administrative purposes.This will bring up the Home page of you WebLogic Server. You have actually verified that you are able to login with these credentials already. However if you want to check the details, navigate to Security Realms, myrealm, Users and Groups tab.Here you could add users to your WebLogic Server which could be used in the later steps. Details on the Groups required for such a custom user to work are exceeding this quick overview and have to be selected with the WebLogic Server Adminstration Guide in mind.Shared Data Services pre-requisites for Load testingOpenScript Preferences have to be set to enable Encryption and provide a default Shared Data Service Connection for Playback.These are pre-requisites you want to use for load testing with Shared Data Services.Please note that the usage of the Connection Parameters (individual directive in the script) for Shared Data Services did not playback reliably in the current version 9.20.0370 of Oracle Load Testing (OLT) and encryption of credentials still seemed to be mandatory as well.General Encryption settingsSelect OpenScript Preferences from the View menu and navigate to the General, Encryption entry in the tree on the left. Select the Encrypt script data option from the list and enter the same password that you used for securing your WebLogic Server Administration Console.Enable global shared data access credentialsSelect OpenScript Preferences from the View menu and navigate to the Playback, Shared Data entry in the tree on the left. Enable the global shared data access credentials and enter the Address, User name and Password determined for your WebLogic Server to host Shared Data Services.Please note, that you may want to replace the localhost in Address with the hosts realname in case you plan to run load tests with Loadtest Agents running on remote systems.Queued Processing of TransactionsEnable Shared Data Services Module in Script PropertiesThe Shared Data Services Module has to be enabled for each Script that wants to employ the Shared Data Service Queue functionality in OpenScript. It can be enabled under the Script menu selecting Script Properties. On the Script Properties Dialog select the Modules section and check Shared Data to enable Shared Data Service Module for your script. Checking the Shared Data Services option will effectively add a line to your script code that adds the sharedData ScriptService to your script class of IteratingVUserScript.@ScriptService oracle.oats.scripting.modules.sharedData.api.SharedDataService sharedData;Record your scriptRecord your script as usual and then add the following things for Queue handling in the Initialize code block, before the first step and after the last step of your critical path and in the Finalize code block.The java code to be added at individual locations is explained in the following sections in full detail.Create a Shared Data Queue in InitializeTo create a Shared Data Queue go to the Java view of your script and enter the following statements to the initialize() code block.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);This will create an instantiation of the Shared Data Queue object named queueA which is maintained for upto 120 minutes.If you want to use the code for multiple scripts, make sure to use a different queue name for each one here and in the subsequent steps. You may even consider to use a dynamic queueName based on filters of your result list being concurrently accessed.Prepare a unique id for each IterationIn order to keep track of individual virtual users in our queue we need to create a unique identifier from the virtual user id and the used username right after retrieving the next record from our databank file.getDatabank("Usernames").getNextDatabankRecord();getVariables().set("usernameValue1","VU_{{@vuid}}_{{@iterationnum}}_{{db.Usernames.Username}}_{{@timestamp}}_{{@random(10000)}}");String usernameValue = getVariables().get("usernameValue1");info("Now running virtual user " + usernameValue);As you can see from the above code block, we have set the OpenScript variable usernameValue1 to VU_{{@vuid}}_{{@iterationnum}}_{{db.Usernames.Username}}_{{@timestamp}}_{{@random(10000)}} which is a concatenation of the virtual user id and the iterationnumber for general uniqueness; as well as the username from our databank, the timestamp and a random number for making it further unique and ease spotting of errors.Not all of these fields are actually required to make it really unique, but adding the queue name may also be considered to help troubleshoot multiple queues.The value is then retrieved with the getVariables.get() method call and assigned to the usernameValue String used throughout the script.Please note that moving the getDatabank("Usernames").getNextDatabankRecord(); call to the initialize block was later considered to remove concurrency of multiple virtual users running with the same userid and therefor accessing the same "My Inbox" in step 6. This will effectively give each virtual user a userid from the databank file. Make sure you have enough userids to remove this second hurdle.Enqueue and attend Queue before Critical PathTo maintain the right order of virtual users being allowed into the critical path of the transaction the following pseudo step has to be added in front of the first critical step. In the case of this example this is right in front of the step where we retrieve the list of actions from which we select the first to be assigned to us.beginStep("[0] Waiting in the Queue", 0);{info("Enqueued virtual user " + usernameValue + " at the end of queueA");sharedData.offerLast("queueA", usernameValue);info("Wait until the user is the first in queueA");String queueValue1 = null;do {// we wait for at least 0.7 seconds before we check the head of the// queue. This is the time it takes one user to move through the// critical path, i.e. pass steps [5] Enter country and [6] Assign// to meThread.sleep(700);queueValue1 = (String) sharedData.peekFirst("queueA");info("The first user in queueA is currently: '" + queueValue1 + "' " + queueValue1.getClass() + " length " + queueValue1.length() );info("The current user is '"+ usernameValue + "' " + usernameValue.getClass() + " length " + usernameValue.length() + ": indexOf " + usernameValue.indexOf(queueValue1) + " equals " + usernameValue.equals(queueValue1) );} while ( queueValue1.indexOf(usernameValue) < 0 );info("Now the user is the first in queueA");}endStep();This will enqueue the username to the tail of our Queue. It will will wait for at least 700 milliseconds, the time it takes for one user to exit the critical path and then compare the head of our queue with it's username. This last step will be repeated while the two are not equal (indexOf less than zero). If they are equal the indexOf will yield a value of zero or larger and we will perform the critical steps.Dequeue after Critical PathAfter the virtual user has left the critical path and complete its last step the following code block needs to dequeue the virtual user. In the case of our example this is right after the action has been actually assigned to the virtual user. This will allow the next virtual user to retrieve the list of actions still available and in turn let him make his selection/assignment.info("Get and remove the current user from the head of queueA");String pollValue1 = (String) sharedData.pollFirst("queueA");The current user is removed from the head of the queue. The next one will now be able to match his username against the head of the queue.Clear and Destroy Queue for FinishWhen the script has completed, it should clear and destroy the queue. This code block can be put in the finish block of your script and/or in a separate script in order to clear and remove the queue in case you have spotted an error or want to reset the queue for some reason.info("Clear queueA");sharedData.clearQueue("queueA");info("Destroy queueA");sharedData.destroyQueue("queueA");The users waiting in queueA are cleared and the queue is destroyed. If you have scripts still executing they will be caught in a loop.I found it better to maintain a separate Reset Queue script which contained only the following code in the initialize() block. I use to call this script to make sure the queue is cleared in between multiple Loadtest runs. This script could also even be added as the first in a larger scenario, which would execute it only once at very start of the Loadtest and make sure the queues do not contain any stale entries.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);info("Clear queueA");sharedData.clearQueue("queueA");This will create a Shared Data Queue instance of queueA and clear all entries from this queue.Monitoring QueueWhile creating the scripts it was useful to monitor the contents, i.e. the current first user in the Queue. The following code block will make sure the Shared Data Queue is accessible in the initialize() block.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);In the run() block the following code will continuously monitor the first element of the Queue and write an informational message with the current username Value to the Result window.info("Monitor the first users in queueA");String queueValue1 = null;do {queueValue1 = (String) sharedData.peekFirst("queueA");if (queueValue1 != null)info("The first user in queueA is currently: '" + queueValue1 + "' " + queueValue1.getClass() + " length " + queueValue1.length() );} while ( true );This script can be run from OpenScript parallel to a loadtest performed by the Oracle Load Test.However it is not recommend to run this in a production loadtest as the performance impact is unknown. Accessing the Queue's head with the peekFirst() method has been reported with about 2 seconds response time by both OpenScript and OTL. It is advised to log a Service Request to see if this could be lowered in future releases of Application Testing Suite, as the pollFirst() and even offerLast() writing to the tail of the Queue usually returned after an average 0.1 seconds.Debugging QueueWhile debugging the scripts the following was useful to remove single entries from its head, i.e. the current first user in the Queue. The following code block will make sure the Shared Data Queue is accessible in the initialize() block.info("Create queueA with life time of 120 minutes");sharedData.createQueue("queueA", 120);In the run() block the following code will remove the first element of the Queue and write an informational message with the current username Value to the Result window.info("Get and remove the current user from the head of queueA");String pollValue1 = (String) sharedData.pollFirst("queueA");info("The first user in queueA was currently: '" + pollValue1 + "' " + pollValue1.getClass() + " length " + pollValue1.length() );ReferencesOracle Functional Testing OpenScript User's Guide Version 9.20 [E15488-05]Chapter 17 Using the Shared Data Modulehttp://download.oracle.com/otn/nt/apptesting/oats-docs-9.21.0030.zipOracle Fusion Middleware Oracle WebLogic Server Administration Console Online Help 11g Release 1 (10.3.4) [E13952-04]Administration Console Online Help - Manage users and groupshttp://download.oracle.com/docs/cd/E17904_01/apirefs.1111/e13952/taskhelp/security/ManageUsersAndGroups.htm

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  • Simple Branching and Merging with SVN

    Its a good idea not to do too much work without checking something into source control.  By too much work I mean typically on the order of a couple of hours at most, and certainly its a good practice to check in anything you have before you leave the office for the day.  But what if your changes break the build (on the build server you do have a build server dont you?) or would cause problems for others on your team if they get the latest code?  The solution with Subversion is branching and merging (incidentally, if youre using Microsoft Visual Studio Team System, you can shelve your changes and share shelvesets with others, which accomplishes many of the same things as branching and merging, but is a bit simpler to do). Getting Started Im going to assume you have Subversion installed along with the nearly ubiquitous client, TortoiseSVN.  See my previous post on installing SVN server if you want to get it set up real quick (you can put it on your workstation/laptop just to learn how it works easily enough). Overview When you know you are going to be working on something that you wont be able to check in quickly, its a good idea to start a branch.  Its also perfectly fine to create the branch after-the-fact (have you ever started something thinking it would be an hour and 4 hours later realized you were nowhere near done?).  In any event, the first thing you need to do is create a branch.  A branch is simply a copy of the current trunk (a typical subversion setup has root directories called trunk, tags, and branches its a good idea to keep this and to put your branches in the branches folder).  Once you have a new branch, you need to switch your working copy so that it is bound to your branch.  As you work,  you may want to merge in changes that are happening in the trunk to your branch, and ultimately when you are done youll want to merge your branch back into the trunk.  When done, you can delete your branch (or not, but it may add clutter).  To sum up: Create a new branch Switch your local working copy to the new branch Develop in the branch (commit changes, etc.) Merge changes from trunk into your branch Merge changes from branch into trunk Delete the branch Create a new branch From the root of your repository, right-click and select TortoiseSVN > Branch/tag as shown at right (click to enlarge).  This will bring up the Copy (Branch / Tag) interface.  By default the From WC at URL: should be pointing at the trunk of your repository.  I recommend (after ensuring that you have the latest version) that you choose to make the copy from the HEAD revision in the repository (the first radio button).  In the To URL: textbox, you should change the URL from /trunk to /branches/NAME_OF_BRANCH.  You can name the branch anything you like, but its often useful to give it your name (if its just for your use) or some useful information (such as a datestamp or a bug/issue ID from that it relates to, or perhaps just the name of the feature you are adding. When youre done with that, enter in a log message for your new branch.  If you want to immediately switch your local working copy to the new branch/tag, check the box at the bottom of the dialog (Switch working copy to new branch/tag).  You can see an example at right. Assuming everything works, you should very quickly see a window telling you the Copy finished, like the one shown below: Switch Local Working Copy to New Branch If you followed the instructions above and checked the box when you created your branch, you dont need to do this step.  However, if you have a branch that already exists and you would like to switch over to working on it, you can do so by using the Switch command.  Youll find it in the explorer context menu under TortoiseSVN > Switch: This brings up a dialog that shows you your current binding, and lets you enter in a new URL to switch to: In the screenshot above, you can see that Im currently bound to a branch, and so I could switch back to the trunk or to another branch.  If youre not sure what to enter here, you can click the [] next to the URL textbox to explore your repository and find the appropriate root URL to use.  Also, the dropdown will show you URLs that might be a good fit (such as the trunk of the current repository). Develop in the Branch Once you have created a branch and switched your working copy to use it,  you can make changes and Commit them as usual.  Your commits are now going into the branch, so they wont impact other users or the build server that are working off of the trunk (or their own branches).  In theory you can keep on doing this forever, but practically its a good idea to periodically merge the trunk into your branch, and/or keep your branches short-lived and merge them back into the trunk before they get too far out of sync. Merge Changes from Trunk into your Branch Once you have been working in a branch for a little while, change to the trunk will have occurred that youll want to merge into your branch.  Its much safer and easier to integrate changes in small increments than to wait for weeks or months and then try to merge in two very different codebases.  To perform the merge, simply go to the root of your branch working copy and right click, select TortoiseSVN->Merge.  Youll be presented with this dialog: In this case you want to leave the default setting, Merge a range of revisions.  Click Next.  Now choose the URL to merge from.  You should select the trunk of your current repository (which should be in the dropdownlist, or you can click the [] to browse your repository for the correct URL).  You can leave everything else blank since you want to merge everything: Click Next.  Again you can leave the default settings.  If you want to do something more granular than everything in the trunk, you can select a different Merge depth, to include merging just one item in the tree.  You can also perform a Test merge to see what changes will take place before you click Merge (which is often a good idea).  Heres what the dialog should look like before you click Merge: After clicking Merge (or Test merge) you should see a confirmation like this (it will say Test Only in the title if you click Test merge): Now you should build your solution, run all of your tests, and verify that your branch still works the way it should, given the updates that youve just integrated from the trunk.  Once everything works, Commit your changes, and then continue with your work on the branch.  Note that until you commit, nothing has actually changed in your branch on the server.  Other team members who may also be working in this branch wont be impacted, etc.  The Merge is purely a client-side operation until you perform a Commit. In a more real-world scenario, you may have conflicts.  When you do, youll be presented with a dialog like this one: Its up to you which option you want to go with.  The more frequently you Merge, the fewer of these youll have to deal with.  Also, be very sure that youre merging the right folders together.  If you try and merge your trunk with some subfolder in your branchs structure, youll end up with all kinds of conflicts and problems.  Fortunately, theyre only on your working copy (unless you commit them!) but if you see something like that, be sure to doublecheck your URL and your local file location. Merge Your Branch Back Into Trunk When youre done working in your branch, its time to pull it back into the trunk.  The first thing you should do is follow the previous steps instructions for merging the latest from the trunk into your branch.  This lets you ensure that what you have in your branch works correctly with the current trunk.  Once youve done that and committed your changes to your branch, youre ready to proceed with this step. Once youre confident your branch is good to go, you should go to its root folder and select TortoiseSVN->Merge (as above) from the explorer right-click menu.  This time, select Reintegrate a branch as shown below: Click Next.  Youll want it to merge with the trunk, which should be the default: Click Next. Leave the default settings: Click Test merge to see a test, and then if all looks good, click Merge.  Note that if you havent checked in your working copy changes, youll see something like this: If on the other hand things are successful: After this step, its likely you are finished working in your branch.  Dont forget to use the ToroiseSVN->Switch command to change your working copy back to the trunk. Delete the Branch You dont have to delete the branch, but over time your branches area of your repository will get cluttered, and in any event if theyre not actively being worked on the branches are just taking up space and adding to later confusion.  Keeping your branches limited to things youre actively working on is simply a good habit to get into, just like making sure your codebase itself remains tidy and not filled with old commented out bits of code. To delete the branch after youre finished with it, the simplest thing to do is choose TortoiseSVN->Repo Browser.  From there, assuming you did this from your branch, it should already be highlighted.  In any event, navigate to your branch in the treeview on the left, and then right-click and select Delete.  Enter a log message if youd like: Click OK, and its gone.  Dont be too afraid of this, though.  You can still get to the files by viewing the log for branches, and selecting a previous revision (anything before the delete action): If for some reason you needed something that was previously in this branch, you could easily get back to any changeset you checked in, so you should have absolutely no fear when it comes to deleting branches youre done with.   Resources If youre using Eclipse, theres a nice write-up of the steps required by Zach Cox that I found helpful here. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Add collison detection to enemy sprites?

    - by xBroak
    i'd like to add the same collision detection used by the player sprite to the enemy sprites or 'creeps' ive added all the relevant code I can see yet collisons are still not being detected and handled, please find below the class, I have no idea what is wrong currently, the list of walls to collide with is 'wall_list' import pygame import pauseScreen as dm import re from pygame.sprite import Sprite from pygame import Rect, Color from random import randint, choice from vec2d import vec2d from simpleanimation import SimpleAnimation import displattxt black = (0,0,0) white = (255,255,255) blue = (0,0,255) green = (101,194,151) global currentEditTool currentEditTool = "Tree" global editMap editMap = False open('MapMaker.txt', 'w').close() def draw_background(screen, tile_img): screen.fill(black) img_rect = tile_img.get_rect() global rect rect = img_rect nrows = int(screen.get_height() / img_rect.height) + 1 ncols = int(screen.get_width() / img_rect.width) + 1 for y in range(nrows): for x in range(ncols): img_rect.topleft = (x * img_rect.width, y * img_rect.height) screen.blit(tile_img, img_rect) def changeTool(): if currentEditTool == "Tree": None elif currentEditTool == "Rock": None def pauseGame(): red = 255, 0, 0 green = 0,255, 0 blue = 0, 0,255 screen.fill(black) pygame.display.update() if editMap == False: choose = dm.dumbmenu(screen, [ 'Resume', 'Enable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("hi") elif choose ==1: global editMap editMap = True elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None else: choose = dm.dumbmenu(screen, [ 'Resume', 'Disable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("Resume") elif choose ==1: print("Dis ME") global editMap editMap = False elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None class Wall(pygame.sprite.Sprite): # Constructor function def __init__(self,x,y,width,height): pygame.sprite.Sprite.__init__(self) self.image = pygame.Surface([width, height]) self.image.fill(green) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertTree(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/tree.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertRock(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/rock.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class Creep(pygame.sprite.Sprite): """ A creep sprite that bounces off walls and changes its direction from time to time. """ change_x=0 change_y=0 def __init__( self, screen, creep_image, explosion_images, field, init_position, init_direction, speed): """ Create a new Creep. screen: The screen on which the creep lives (must be a pygame Surface object, such as pygame.display) creep_image: Image (surface) object for the creep explosion_images: A list of image objects for the explosion animation. field: A Rect specifying the 'playing field' boundaries. The Creep will bounce off the 'walls' of this field. init_position: A vec2d or a pair specifying the initial position of the creep on the screen. init_direction: A vec2d or a pair specifying the initial direction of the creep. Must have an angle that is a multiple of 45 degres. speed: Creep speed, in pixels/millisecond (px/ms) """ Sprite.__init__(self) self.screen = screen self.speed = speed self.field = field self.rect = creep_image.get_rect() # base_image holds the original image, positioned to # angle 0. # image will be rotated. # self.base_image = creep_image self.image = self.base_image self.explosion_images = explosion_images # A vector specifying the creep's position on the screen # self.pos = vec2d(init_position) # The direction is a normalized vector # self.direction = vec2d(init_direction).normalized() self.state = Creep.ALIVE self.health = 15 def is_alive(self): return self.state in (Creep.ALIVE, Creep.EXPLODING) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def update(self, time_passed, walls): """ Update the creep. time_passed: The time passed (in ms) since the previous update. """ if self.state == Creep.ALIVE: # Maybe it's time to change the direction ? # self._change_direction(time_passed) # Make the creep point in the correct direction. # Since our direction vector is in screen coordinates # (i.e. right bottom is 1, 1), and rotate() rotates # counter-clockwise, the angle must be inverted to # work correctly. # self.image = pygame.transform.rotate( self.base_image, -self.direction.angle) # Compute and apply the displacement to the position # vector. The displacement is a vector, having the angle # of self.direction (which is normalized to not affect # the magnitude of the displacement) # displacement = vec2d( self.direction.x * self.speed * time_passed, self.direction.y * self.speed * time_passed) self.pos += displacement # When the image is rotated, its size is changed. # We must take the size into account for detecting # collisions with the walls. # self.image_w, self.image_h = self.image.get_size() bounds_rect = self.field.inflate( -self.image_w, -self.image_h) if self.pos.x < bounds_rect.left: self.pos.x = bounds_rect.left self.direction.x *= -1 elif self.pos.x > bounds_rect.right: self.pos.x = bounds_rect.right self.direction.x *= -1 elif self.pos.y < bounds_rect.top: self.pos.y = bounds_rect.top self.direction.y *= -1 elif self.pos.y > bounds_rect.bottom: self.pos.y = bounds_rect.bottom self.direction.y *= -1 # collision detection old_x=bounds_rect.left new_x=old_x+self.direction.x bounds_rect.left = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes bounds_rect.left=old_x old_y=self.pos.y new_y=old_y+self.direction.y self.pos.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.pos.y=old_y elif self.state == Creep.EXPLODING: if self.explode_animation.active: self.explode_animation.update(time_passed) else: self.state = Creep.DEAD self.kill() elif self.state == Creep.DEAD: pass #------------------ PRIVATE PARTS ------------------# # States the creep can be in. # # ALIVE: The creep is roaming around the screen # EXPLODING: # The creep is now exploding, just a moment before dying. # DEAD: The creep is dead and inactive # (ALIVE, EXPLODING, DEAD) = range(3) _counter = 0 def _change_direction(self, time_passed): """ Turn by 45 degrees in a random direction once per 0.4 to 0.5 seconds. """ self._counter += time_passed if self._counter > randint(400, 500): self.direction.rotate(45 * randint(-1, 1)) self._counter = 0 def _point_is_inside(self, point): """ Is the point (given as a vec2d) inside our creep's body? """ img_point = point - vec2d( int(self.pos.x - self.image_w / 2), int(self.pos.y - self.image_h / 2)) try: pix = self.image.get_at(img_point) return pix[3] > 0 except IndexError: return False def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def _explode(self): """ Starts the explosion animation that ends the Creep's life. """ self.state = Creep.EXPLODING pos = ( self.pos.x - self.explosion_images[0].get_width() / 2, self.pos.y - self.explosion_images[0].get_height() / 2) self.explode_animation = SimpleAnimation( self.screen, pos, self.explosion_images, 100, 300) global remainingCreeps remainingCreeps-=1 if remainingCreeps == 0: print("all dead") def draw(self): """ Blit the creep onto the screen that was provided in the constructor. """ if self.state == Creep.ALIVE: # The creep image is placed at self.pos. To allow for # smooth movement even when the creep rotates and the # image size changes, its placement is always # centered. # self.draw_rect = self.image.get_rect().move( self.pos.x - self.image_w / 2, self.pos.y - self.image_h / 2) self.screen.blit(self.image, self.draw_rect) # The health bar is 15x4 px. # health_bar_x = self.pos.x - 7 health_bar_y = self.pos.y - self.image_h / 2 - 6 self.screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) self.screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) elif self.state == Creep.EXPLODING: self.explode_animation.draw() elif self.state == Creep.DEAD: pass def mouse_click_event(self, pos): """ The mouse was clicked in pos. """ if self._point_is_inside(vec2d(pos)): self._decrease_health(3) #begin new player class Player(pygame.sprite.Sprite): change_x=0 change_y=0 frame = 0 def __init__(self,x,y): pygame.sprite.Sprite.__init__(self) # LOAD PLATER IMAGES # Set height, width self.images = [] for i in range(1,17): img = pygame.image.load("images/player/" + str(i)+".png").convert() #player images img.set_colorkey(white) self.images.append(img) self.image = self.images[0] self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x self.health = 15 self.image_w, self.image_h = self.image.get_size() health_bar_x = self.rect.x - 7 health_bar_y = self.rect.y - self.image_h / 2 - 6 screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def update(self,walls): # collision detection old_x=self.rect.x new_x=old_x+self.change_x self.rect.x = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.x=old_x old_y=self.rect.y new_y=old_y+self.change_y self.rect.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.y=old_y # right to left if self.change_x < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 # Grab the image, divide by 4 # every 4 frames. self.image = self.images[self.frame//4] # Move left to right. # images 4...7 instead of 0...3. if self.change_x > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4] if self.change_y > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4] if self.change_y < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4+4] score = 0 # initialize pyGame pygame.init() # 800x600 sized screen global screen screen = pygame.display.set_mode([800, 600]) screen.fill(black) #bg_tile_img = pygame.image.load('images/map/grass.png').convert_alpha() #draw_background(screen, bg_tile_img) #pygame.display.flip() # Set title pygame.display.set_caption('Test') #background = pygame.Surface(screen.get_size()) #background = background.convert() #background.fill(black) # Create the player player = Player( 50,50 ) player.rect.x=50 player.rect.y=50 movingsprites = pygame.sprite.RenderPlain() movingsprites.add(player) # Make the walls. (x_pos, y_pos, width, height) global wall_list wall_list=pygame.sprite.RenderPlain() wall=Wall(0,0,10,600) # left wall wall_list.add(wall) wall=Wall(10,0,790,10) # top wall wall_list.add(wall) #wall=Wall(10,200,100,10) # poke wall wall_list.add(wall) wall=Wall(790,0,10,600) #(x,y,thickness, height) wall_list.add(wall) wall=Wall(10,590,790,10) #(x,y,thickness, height) wall_list.add(wall) f = open('MapMaker.txt') num_lines = sum(1 for line in f) print(num_lines) lineCount = 0 with open("MapMaker.txt") as infile: for line in infile: f = open('MapMaker.txt') print(line) coords = line.split(',') #print(coords[0]) #print(coords[1]) #print(coords[2]) #print(coords[3]) #print(coords[4]) if "tree" in line: print("tree in") wall=insertTree(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4]) wall_list.add(wall) elif "rock" in line: print("rock in") wall=insertRock(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4] ) wall_list.add(wall) width = 20 height = 540 height = height - 48 for i in range(0,23): width = width + 32 name = insertTree(width,540,790,10,"tree") #wall_list.add(name) name = insertTree(width,height,690,10,"tree") #wall_list.add(name) CREEP_SPAWN_TIME = 200 # frames creep_spawn = CREEP_SPAWN_TIME clock = pygame.time.Clock() bg_tile_img = pygame.image.load('images/map/grass.png').convert() img_rect = bg_tile_img FIELD_RECT = Rect(50, 50, 700, 500) CREEP_FILENAMES = [ 'images/player/1.png', 'images/player/1.png', 'images/player/1.png'] N_CREEPS = 3 creep_images = [ pygame.image.load(filename).convert_alpha() for filename in CREEP_FILENAMES] explosion_img = pygame.image.load('images/map/tree.png').convert_alpha() explosion_images = [ explosion_img, pygame.transform.rotate(explosion_img, 90)] creeps = pygame.sprite.RenderPlain() done = False #bg_tile_img = pygame.image.load('images/map/grass.png').convert() #draw_background(screen, bg_tile_img) totalCreeps = 0 remainingCreeps = 3 while done == False: creep_images = pygame.image.load("images/player/1.png").convert() creep_images.set_colorkey(white) draw_background(screen, bg_tile_img) if len(creeps) != N_CREEPS: if totalCreeps < N_CREEPS: totalCreeps = totalCreeps + 1 print(totalCreeps) creeps.add( Creep( screen=screen, creep_image=creep_images, explosion_images=explosion_images, field=FIELD_RECT, init_position=( randint(FIELD_RECT.left, FIELD_RECT.right), randint(FIELD_RECT.top, FIELD_RECT.bottom)), init_direction=(choice([-1, 1]), choice([-1, 1])), speed=0.01)) for creep in creeps: creep.update(60,wall_list) creep.draw() for event in pygame.event.get(): if event.type == pygame.QUIT: done=True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_RIGHT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_UP: player.changespeed(0,-2) creep.changespeed(0,-2) if event.key == pygame.K_DOWN: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_ESCAPE: pauseGame() if event.key == pygame.K_1: global currentEditTool currentEditTool = "Tree" changeTool() if event.key == pygame.K_2: global currentEditTool currentEditTool = "Rock" changeTool() if event.type == pygame.KEYUP: if event.key == pygame.K_LEFT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_RIGHT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_UP: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_DOWN: player.changespeed(0,-2) creep.changespeed(0,-2) if event.type == pygame.MOUSEBUTTONDOWN and pygame.mouse.get_pressed()[0]: for creep in creeps: creep.mouse_click_event(pygame.mouse.get_pos()) if editMap == True: x,y = pygame.mouse.get_pos() if currentEditTool == "Tree": name = insertTree(x-10,y-25, 10 , 10, "tree") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") image = pygame.image.load("images/map/tree.png").convert() screen.blit(image, (30,10)) pygame.display.flip() f.write(str(x) + "," + str(y) + ",790,10, tree\n") #f.write("wall=insertTree(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") elif currentEditTool == "Rock": name = insertRock(x-10,y-25, 10 , 10,"rock") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") f.write(str(x) + "," + str(y) + ",790,10,rock\n") #f.write("wall=insertRock(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") else: None #pygame.display.flip() player.update(wall_list) movingsprites.draw(screen) wall_list.draw(screen) pygame.display.flip() clock.tick(60) pygame.quit()

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  • PASS Summit Feedback

    - by Rob Farley
    PASS Feedback came in last week. I also saw my dentist for some fillings... At the PASS Summit this year, I delivered a couple of regular sessions and a Lightning Talk. People told me they enjoyed it, but when the rankings came out, they showed that I didn’t score particularly well. Brent Ozar was keen to discuss it with me. Brent: PASS speaker feedback is out. You did two sessions and a Lightning Talk. How did you go? Rob: Not so well actually, thanks for asking. Brent: Ha! Sorry. Of course you know that's why I wanted to discuss this with you. I was in one of your sessions at SQLBits in the UK a month before PASS, and I thought you rocked. You've got a really good and distinctive delivery style.  Then I noticed your talks were ranked in the bottom quarter of the Summit ratings and wanted to discuss it. Rob: Yeah, I know. You did ask me if we could do this...  I should explain – my presentation style is not the stereotypical IT conference one. I throw in jokes, and try to engage the audience thoroughly. I find many talks amazingly dry, and I guess I try to buck that trend. I also run training courses, and find that I get a lot of feedback from people thanking me for keeping things interesting. That said, I also get feedback criticising me for my style, and that’s basically what’s happened here. For the rest of this discussion, let’s focus on my talk about the Incredible Shrinking Execution Plan, which I considered to be my main talk. Brent: I thought that session title was the very best one at the entire Summit, and I had it on my recommended sessions list.  In four words, you managed to sum up the topic and your sense of humor.  I read that and immediately thought, "People need to be in this session," and then it didn't score well.  Tell me about your scores. Rob: The questions on the feedback form covered the usefulness of the information, the speaker’s presentation skills, their knowledge of the subject, how well the session was described, the amount of time allocated, and the quality of the presentation materials. Brent: Presentation materials? But you don’t do slides.  Did they rate your thong? Rob: No-one saw my flip-flops in this talk, Brent. I created a script in Management Studio, and published that afterwards, but I think people will have scored that question based on the lack of slides. I wasn’t expecting to do particularly well on that one. That was the only section that didn’t have 5/5 as the most popular score. Brent: See, that sucks, because cookbook-style scripts are often some of my favorites.  Adam Machanic's Service Broker workbench series helped me immensely when I was prepping for the MCM.  As an attendee, I'd rather have a commented script than a slide deck.  So how did you rank so low? Rob: When I look at the scores that you got (based on your blog post), you got very few scores below 3 – people that felt strong enough about your talk to post a negative score. In my scores, between 5% and 10% were below 3 (except on the question about whether I knew my stuff – I guess I came as knowledgeable). Brent: Wow – so quite a few people really didn’t like your talk then? Rob: Yeah. Mind you, based on the comments, some people really loved it. I’d like to think that there would be a certain portion of the room who may have rated the talk as one of the best of the conference. Some of my comments included “amazing!”, “Best presentation so far!”, “Wow, best session yet”, “fantastic” and “Outstanding!”. I think lots of talks can be “Great”, but not so many talks can be “Outstanding” without the word losing its meaning. One wrote “Pretty amazing presentation, considering it was completely extemporaneous.” Brent: Extemporaneous, eh? Rob: Yeah. I guess they don’t realise how much preparation goes into coming across as unprepared. In many ways it’s much easier to give a written speech than to deliver a presentation without slides as a prompt. Brent: That delivery style, the really relaxed, casual, college-professor approach was one of the things I really liked about your presentation at SQLbits.  As somebody who presents a lot, I "get" it - I know how hard it is to come off as relaxed and comfortable with your own material.  It's like improv done by jazz players and comedians - if you've never tried it, you don't realize how hard it is.  People also don't realize how hard it is to make a tough subject fun. Rob: Yeah well... There will be people writing comments on this post that say I wasn't trying to make the subject fun, and that I was making it all about me. Sometimes the style works, sometimes it doesn't. Most of the comments mentioned the fact that I tell jokes, some in a nice way, but some not so much (and it wasn't just a PASS thing - that's the mix of feedback I generally get). One comment at PASS was: “great stand up comedian - not what I'm looking for at pass”, and there were certainly a few that said “too many jokes”. I’m not trying to do stand-up – jokes are my way of engaging with the audience while I demonstrate some of the amazing things that the Query Optimizer can do if you write your queries the right way. Some people didn’t think it was technical enough, but I’ve also had some people tell me that the concepts I’m explaining are deep and profound. Brent: To me, that's a hallmark of a great explanation - when someone says, "But of course it has to work that way - how could it work any other way?  It seems so simple and logical."  Well, sure it does when it's explained correctly, but now pick up any number of thick SQL Server books and try to understand the Redundant Joins concept.  I guarantee it'll take more than 45 minutes. Rob: Some people in my audiences realise that, but definitely not everyone. There's only so much you can tell someone that something is profound. Generally it's something that they either have an epiphany on or not. I like to lull my audience into knowing what's going on, and do something that surprises them. Gain their trust, build a rapport, and then show them the deeper truth of what just happened. Brent: So you've learned your lesson about presentation scores, right?  From here on out, you're going to be dry, humorless, and all your presentations will consist of you reading bullet points off the screen. Rob: No Brent, I’m not. I'm also not going to suggest that most presentations at PASS are like that. No-one tries to present like that. There's a big space to occupy between what "dry and humourless" and me. My difference is to focus on the relationship I have with the crowd, rather than focussing on delivering the perfect session. I want to see people smiling and know they're relaxed. I think most presenters focus on the material, which is completely reasonable and safe. I remember once hearing someone talking about product creation. They talked about mediocrity. They said that one of the worst things that people can ever say about your product is that it’s “good”. What you want is for 10% of the world to love it enough to want to buy it. If 10% the world gave me a dollar, I’d have more money than I could ever use (assuming it wasn’t the SAME dollar they were giving me I guess). Brent: It's the Raving Fans theory.  It's better to have a small number of raving customers than a large number of almost-but-not-really customers who don't care that much about your product or service.  I know exactly how you feel - when I got survey feedback from my Quest video presentation when I was dressed up in a Richard Simmons costume, some of the attendees said I was unprofessional and distracting.  Some of the attendees couldn't get enough and Photoshopped all kinds of stuff into the screen captures.  On a whole, I probably didn't score that well, and I'm fine with that.  It sucks to look at the scores though - do those lower scores bother you? Rob: Of course they do. It hurts deeply. I open myself up and give presentations in a very personal way. All presenters do that, and we all feel the pain of negative feedback. I hate coming 146th & 162nd out of 185, but have to acknowledge that many sessions did worse still. Plus, once I feel the wounds have healed, I’ll be able to remember that there are people in the world that rave about my presentation style, and figure that people will hopefully talk about me. One day maybe those people that don’t like my presentation style will stay away and I might be able to score better. You don’t pay to hear country music if you prefer western... Lots of people find chili too spicy, but it’s still a popular food. Brent: But don’t you want to appeal to everyone? Rob: I do, but I don’t want to be lukewarm as in Revelation 3:16. I’d rather disgust and be discussed. Well, maybe not ‘disgust’, but I don’t want to conform. Conformity just isn’t the same any more. I’m not sure I’ve ever been one to do that. I try not to offend, but definitely like to be different. Brent: Count me among your raving fans, sir.  Where can we see you next? Rob: Considering I live in Adelaide in Australia, I’m not about to appear at anyone’s local SQL Saturday. I’m still trying to plan which events I’ll get to in 2011. I’ve submitted abstracts for TechEd North America, but won’t hold my breath. I’m also considering the SQLBits conferences in the UK in April, PASS in October, and I’m sure I’ll do some LiveMeeting presentations for user groups. Online, people download some of my recent SQLBits presentations at http://bit.ly/RFSarg and http://bit.ly/Simplification though. And they can download a 5-minute MP3 of my Lightning Talk at http://www.lobsterpot.com.au/files/Collation.mp3, in which I try to explain the idea behind collation, using thongs as an example. Brent: I was in the audience for http://bit.ly/RFSarg. That was a great presentation. Rob: Thanks, Brent. Now where’s my dollar?

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  • BizTalk 2009 - Naming Guidelines

    - by StuartBrierley
    The following is effectively a repost of the BizTalk 2004 naming guidlines that I have previously detailed.  I have posted these again for completeness under BizTalk 2009 and to allow an element of separation in case I find some reason to amend these for BizTalk 2009. These guidlines should be universal across any version of BizTalk you may wish to apply them to. General Rules All names should be named with a Pascal convention. Project Namespaces For message schemas: [CompanyName].XML.Schemas.[FunctionalName]* Examples:  ABC.XML.Schemas.Underwriting DEF.XML.Schemas.MarshmellowTradingExchange * Donates potential for multiple levels of functional name, such as Underwriting.Dictionary.Valuation For web services: [CompanyName].Web.Services.[FunctionalName] Examples: ABC.Web.Services.OrderJellyBeans For the main BizTalk Projects: [CompanyName].BizTalk.[AssemblyType].[FunctionalName]* Examples: ABC.BizTalk.Mappings.Underwriting ABC.BizTalk.Orchestrations.Underwriting * Donates potential for multiple levels of functional name, such as Mappings.Underwriting.Valuations Assemblies BizTalk Assembly names should match the associated Project Namespace, such as ABC.BizTalk.Mappings.Underwriting. This pertains to the formal assembly name and the DLL name. The Solution name should take the name of the main project within the solution, and also therefore the namespace for that project. Although long names such as this can be unwieldy to work with, the benefits of having the full scope available when the assemblies are installed on the target server are generally judged to outweigh this inconvenience. Messaging Artifacts Artifact Standard Notes Example Schema <DescriptiveName>.xsd   .NET Type name should match, without file extension.    .NET Namespace will likely match assembly name. PurchaseOrderAcknowledge_FF.xsd  or FNMA100330_FF.xsd Property Schema <DescriptiveName>.xsd Should be named to reflect possible common usage across multiple schemas  IspecMessagePropertySchema.xsd UnderwritingOrchestrationKeys.xsd Map <SourceSchema>2<DestinationSchema>.btm Exceptions to this may be made where the source and destination schemas share the majority of the name, such as in mainframe web service maps InstructionResponse2CustomEmailRequest.btm (exception example) AccountCustomerAddressSummaryRequest2MainframeRequest.btm Orchestration <DescriptiveName>.odx   GetValuationReports.odx SendMTEDecisionResponse.odx Send/Receive Pipeline <DescriptiveName>.btp   ValidatingXMLReceivePipeline.btp FlatFileAssembler.btp Receive Port A plainly worded phrase that will clearly explain the function.    FraudPreventionServices LetterProcessing   Receive Location A plainly worded phrase that will clearly explain the function.  ? Do we want to include the transport type here ? Arrears Web Service Send Port Group A plainly worded phrase that will clearly explain the function.   Customer Updates Send Port A plainly worded phrase that will clearly explain the function.    ABCProductUpdater LogLendingPolicyOutput Parties A meaningful name for a Trading Partner. If dealing with multiple entities within a Trading Partner organization, the Organization name could be used as a prefix.   Roles A meaningful name for the role that a Trading Partner plays.     Orchestration Workflow Shapes Shape Standard Notes Example Scopes <DescriptionOfContainedWork> or <DescOfcontainedWork><TxType>   Including info about transaction type may be appropriate in some situations where it adds significant documentation value to the diagram. HandleReportResponse         Receive Receive<MessageName> Typically, MessageName will be the same as the name of the message variable that is being received “into”. ReceiveReportResponse Send Send<MessageName> Typically, MessageName will be the same as the name of the message variable that is being sent. SendValuationDetailsRequest Expression <DescriptionOfEffect> Expression shapes should be named to describe the net effect of the expression, similar to naming a method.  The exception to this is the case where the expression is interacting with an external .NET component to perform a function that overlaps with existing BizTalk functionality – use closest BizTalk shape for this case. CreatePrintXML Decide <DescriptionOfDecision> A description of what will be decided in the “if” branch Report Type? Perform MF Save? If-Branch <DescriptionOfDecision> A (potentially abbreviated) description of what is being decided Mortgage Valuation Yes Else-Branch Else Else-branch shapes should always be named “Else” Else Construct Message (Assign) Create<Message> (for Construct)     <ExpressionDescription> (for expression) If a Construct shape contains a message assignment, it should be prefixed with “Create” followed by an abbreviated name of the message being assigned.    The actual message assignment shape contained should be named to describe the expression that is contained. CreateReportDataMV   which contains expression: ExtractReportData Construct Message (Transform) Create<Message> (for Construct)   <SourceSchema>2<DestSchema> (for transform) If a Construct shape contains a message transform, it should be prefixed with “Create” followed by an abbreviated name of the message being assigned.   The actual message transform shape contained should generally be named the same as the called map.  CreateReportDataMV   which contains transform: ReportDataMV2ReportDataMV                 Construct Message (containing multiple shapes)   If a Construct Message shape uses multiple assignments or transforms, the overall shape should be named to communicate the net effect, using no prefix.     Call/Start Orchestration Call<OrchestrationName>   Start<OrchestrationName>     Throw Throw<ExceptionType> The corresponding variable name for the exception type should (often) be the same name as the exception type, only camel-cased. ThrowRuleException, which references the “ruleException” variable.     Parallel <DescriptionOfParallelWork> Parallel shapes should be named by a description of what work will be done in parallel   Delay <DescriptionOfWhatWaitingFor> Delay shapes should be named by a description of what is being waited for.  POAcknowledgeTimeout Listen <DescriptionOfOutcomes> Listen shapes should be named by a description that captures (to the degree possible) all the branches of the Listen shape POAckOrTimeout FirstShippingBid Loop <DescriptionOfLoop> A (potentially abbreviated) description of what the loop is. ForEachValuationReport WhileErrorFlagTrue Role Link   See “Roles” in messaging naming conventions above.   Suspend <ReasonDescription> Describe what action an administrator must take to resume the orchestration.  More detail can be passed to error property – and should include what should be done by the administrator before resuming the orchestration. ReEstablishCreditLink Terminate <ReasonDescription> Describe why the orchestration terminated.  More detail can be passed to error property. TimeoutsExpired Call Rules Call<PolicyName> The policy name may need to be abbreviated. CallLendingPolicy Compensate Compensate or Compensate<TxName> If the shape compensates nested transactions, names should be suffixed with the name of the nested transaction – otherwise it should simple be Compensate. CompensateTransferFunds Orchestration Types Type Standard Notes Example Multi-Part Message Types <LogicalDocumentType>   Multi-part types encapsulate multiple parts.  The WSDL spec indicates “parts are a flexible mechanism for describing the logical abstract content of a message.”  The name of the multi-part type should correspond to the “logical” document type, i.e. what the sum of the parts describes. InvoiceReceipt   (which might encapsulate an invoice acknowledgement and a payment voucher.) Multi-Part Messsage Part <SchemaNameOfPart> Should be named (most often) simply for the schema (or simple type) associated with the part. InvoiceHeader Messages <SchemaName> or <MuliPartMessageTypeName> Should be named based on the corresponding schema type or multi-part message type.  If there is more than one variable of a type, name for its use within the orchestration. ReportDataMV UpdatedReportDataMV Variables <DescriptiveName>   TargetFilePath StringProcessor Port Types <FunctionDescription>PortType Should be named to suggest the nature of an endpoint, with pascal casing and suffixed with “PortType”.   If there will be more than one Port for a Port Type, the Port Type should be named according to the abstract service supplied.   The WSDL spec indicates port types are “a named set of abstract operations and the abstract messages involved” that also encapsulates the message pattern (i.e. one-way, request-response, solicit-response) that all operations on the port type adhere to. ReceiveReportResponsePortType  or CallEAEPortType (This is a two way port, so Receove or Send alone would not be appropriate.  Could have been ProcessEAERequestPortType etc....) Ports <FunctionDescription>Port Should be named to suggest a grouping of functionality, with pascal casing and suffixed with “Port.”  ReceiveReportResponsePort CallEAEPort Correlation types <DescriptiveName> Should be named based on the logical name of what is being used to correlate.  PurchaseOrderNumber Correlation sets <DescriptiveName> Should be named based on the corresponding correlation type.  If there is more than one, it should be named to reflect its specific purpose within the orchestration.   PurchaseOrderNumber Orchestration parameters <DescriptiveName> Should be named to match the caller’s names for the corresponding variables where appropriate.

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  • Demystifying Silverlight Dependency Properties

    - by dwahlin
    I have the opportunity to teach a lot of people about Silverlight (amongst other technologies) and one of the topics that definitely confuses people initially is the concept of dependency properties. I confess that when I first heard about them my initial thought was “Why do we need a specialized type of property?” While you can certainly use standard CLR properties in Silverlight applications, Silverlight relies heavily on dependency properties for just about everything it does behind the scenes. In fact, dependency properties are an essential part of the data binding, template, style and animation functionality available in Silverlight. They simply back standard CLR properties. In this post I wanted to put together a (hopefully) simple explanation of dependency properties and why you should care about them if you’re currently working with Silverlight or looking to move to it.   What are Dependency Properties? XAML provides a great way to define layout controls, user input controls, shapes, colors and data binding expressions in a declarative manner. There’s a lot that goes on behind the scenes in order to make XAML work and an important part of that magic is the use of dependency properties. If you want to bind data to a property, style it, animate it or transform it in XAML then the property involved has to be a dependency property to work properly. If you’ve ever positioned a control in a Canvas using Canvas.Left or placed a control in a specific Grid row using Grid.Row then you’ve used an attached property which is a specialized type of dependency property. Dependency properties play a key role in XAML and the overall Silverlight framework. Any property that you bind, style, template, animate or transform must be a dependency property in Silverlight applications. You can programmatically bind values to controls and work with standard CLR properties, but if you want to use the built-in binding expressions available in XAML (one of my favorite features) or the Binding class available through code then dependency properties are a necessity. Dependency properties aren’t needed in every situation, but if you want to customize your application very much you’ll eventually end up needing them. For example, if you create a custom user control and want to expose a property that consumers can use to change the background color, you have to define it as a dependency property if you want bindings, styles and other features to be available for use. Now that the overall purpose of dependency properties has been discussed let’s take a look at how you can create them. Creating Dependency Properties When .NET first came out you had to write backing fields for each property that you defined as shown next: Brush _ScheduleBackground; public Brush ScheduleBackground { get { return _ScheduleBackground; } set { _ScheduleBackground = value; } } Although .NET 2.0 added auto-implemented properties (for example: public Brush ScheduleBackground { get; set; }) where the compiler would automatically generate the backing field used by get and set blocks, the concept is still the same as shown in the above code; a property acts as a wrapper around a field. Silverlight dependency properties replace the _ScheduleBackground field shown in the previous code and act as the backing store for a standard CLR property. The following code shows an example of defining a dependency property named ScheduleBackgroundProperty: public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), null);   Looking through the code the first thing that may stand out is that the definition for ScheduleBackgroundProperty is marked as static and readonly and that the property appears to be of type DependencyProperty. This is a standard pattern that you’ll use when working with dependency properties. You’ll also notice that the property explicitly adds the word “Property” to the name which is another standard you’ll see followed. In addition to defining the property, the code also makes a call to the static DependencyProperty.Register method and passes the name of the property to register (ScheduleBackground in this case) as a string. The type of the property, the type of the class that owns the property and a null value (more on the null value later) are also passed. In this example a class named Scheduler acts as the owner. The code handles registering the property as a dependency property with the call to Register(), but there’s a little more work that has to be done to allow a value to be assigned to and retrieved from the dependency property. The following code shows the complete code that you’ll typically use when creating a dependency property. You can find code snippets that greatly simplify the process of creating dependency properties out on the web. The MVVM Light download available from http://mvvmlight.codeplex.com comes with built-in dependency properties snippets as well. public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), null); public Brush ScheduleBackground { get { return (Brush)GetValue(ScheduleBackgroundProperty); } set { SetValue(ScheduleBackgroundProperty, value); } } The standard CLR property code shown above should look familiar since it simply wraps the dependency property. However, you’ll notice that the get and set blocks call GetValue and SetValue methods respectively to perform the appropriate operation on the dependency property. GetValue and SetValue are members of the DependencyObject class which is another key component of the Silverlight framework. Silverlight controls and classes (TextBox, UserControl, CompositeTransform, DataGrid, etc.) ultimately derive from DependencyObject in their inheritance hierarchy so that they can support dependency properties. Dependency properties defined in Silverlight controls and other classes tend to follow the pattern of registering the property by calling Register() and then wrapping the dependency property in a standard CLR property (as shown above). They have a standard property that wraps a registered dependency property and allows a value to be assigned and retrieved. If you need to expose a new property on a custom control that supports data binding expressions in XAML then you’ll follow this same pattern. Dependency properties are extremely useful once you understand why they’re needed and how they’re defined. Detecting Changes and Setting Defaults When working with dependency properties there will be times when you want to assign a default value or detect when a property changes so that you can keep the user interface in-sync with the property value. Silverlight’s DependencyProperty.Register() method provides a fourth parameter that accepts a PropertyMetadata object instance. PropertyMetadata can be used to hook a callback method to a dependency property. The callback method is called when the property value changes. PropertyMetadata can also be used to assign a default value to the dependency property. By assigning a value of null for the final parameter passed to Register() you’re telling the property that you don’t care about any changes and don’t have a default value to apply. Here are the different constructor overloads available on the PropertyMetadata class: PropertyMetadata Constructor Overload Description PropertyMetadata(Object) Used to assign a default value to a dependency property. PropertyMetadata(PropertyChangedCallback) Used to assign a property changed callback method. PropertyMetadata(Object, PropertyChangedCalback) Used to assign a default property value and a property changed callback.   There are many situations where you need to know when a dependency property changes or where you want to apply a default. Performing either task is easily accomplished by creating a new instance of the PropertyMetadata class and passing the appropriate values to its constructor. The following code shows an enhanced version of the initial dependency property code shown earlier that demonstrates these concepts: public Brush ScheduleBackground { get { return (Brush)GetValue(ScheduleBackgroundProperty); } set { SetValue(ScheduleBackgroundProperty, value); } } public static readonly DependencyProperty ScheduleBackgroundProperty = DependencyProperty.Register("ScheduleBackground", typeof(Brush), typeof(Scheduler), new PropertyMetadata(new SolidColorBrush(Colors.LightGray), ScheduleBackgroundChanged)); private static void ScheduleBackgroundChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var scheduler = d as Scheduler; scheduler.Background = e.NewValue as Brush; } The code wires ScheduleBackgroundProperty to a property change callback method named ScheduleBackgroundChanged. What’s interesting is that this callback method is static (as is the dependency property) so it gets passed the instance of the object that owns the property that has changed (otherwise we wouldn’t be able to get to the object instance). In this example the dependency object is cast to a Scheduler object and its Background property is assigned to the new value of the dependency property. The code also handles assigning a default value of LightGray to the dependency property by creating a new instance of a SolidColorBrush. To Sum Up In this post you’ve seen the role of dependency properties and how they can be defined in code. They play a big role in XAML and the overall Silverlight framework. You can think of dependency properties as being replacements for fields that you’d normally use with standard CLR properties. In addition to a discussion on how dependency properties are created, you also saw how to use the PropertyMetadata class to define default dependency property values and hook a dependency property to a callback method. The most important thing to understand with dependency properties (especially if you’re new to Silverlight) is that they’re needed if you want a property to support data binding, animations, transformations and styles properly. Any time you create a property on a custom control or user control that has these types of requirements you’ll want to pick a dependency property over of a standard CLR property with a backing field. There’s more that can be covered with dependency properties including a related property called an attached property….more to come.

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