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• Web Services Primer for a WinForms Developer?

  - by Unicorns

  I've been writing client/server applications with Winforms for about six years now, but I have yet to venture into the web space (neither ASP.NET nor web services). Given the direction that the job market has been heading for some time and the fact that I have a basic curiosity, I'd like to get involved with writing web services, but I don't know where to start. I've read about various options (XML/SOAP vs. JSON, REST vs...well, actually I don't know what it's called, etc.), but I'm not sure what sort of criteria are in play when making the determination to use one or the other. Obviously, I'd like to leverage the tools that I have (Visual Studio, the .NET framework, etc.) without hamstringing myself into only targeting a particular audience (i.e. writing the service in such a way as to make it difficult to consume from a Windows Mobile/Android/iPhone client, for example). For the record, my plan--for now--is to use WCF for my web service development, but I'm open to using another .NET approach if that's advisable. I realize that this question is pretty open-ended so it may get closed, but here are some things I'm wondering: What are some things to consider when choosing the type of web service (REST, etc.) I intend to write? Is it possible (and, if so, feasible) to move from one approach to another? Can web services be written in an event-driven way? As I said I'm a Winforms developer, so I'm used to objects raising events for me to react to. For instance, if I have two clients connected to my service, is there a way for me to "push" information to one of them as a result of an action by the other? If this is possible, is this advisable or am I just not thinking about it correctly? What authentication mechanisms seem to work best for public-facing services? What about if I plan to have different types of OS'es and clients connecting to the service? Is there a generally accepted platform-agnostic approach? In the line of authentication, is this something that I should be doing myself (authenticating an managing sessions, etc.) or is this something should be handled at the framework level and I just define exactly how it should work? If that's the case, how do I tell who the requester has authenticated themselves as? I started writing an authentication mechanism (simple username/password combinations stored in the database and a corresponding session table with a GUID key) within my service and just requiring that key to be passed with every operation (other than logging in, of course), but I want to make sure that I'm not reinventing the wheel here. However, I also don't want to clutter up the server with a bunch of machine user accounts just to use Basic authentication. I'm also under the impression that Digest (and of course Windows) authentication requires a machine (or AD) user account.

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• How do I add values to semi-complex JSON object?

  - by Nick Verheijen

  I'm fairly new to using JSON objects and I'm kinda stuck. I've got an JSON object that was converted from this array: Array ( [status] => success [id] => 1 [name] => Zone 1 [description] => Awesome zone deze.. [tiles] => Array ( // Column for the tile grid [0] => Array ( // Row for the tile grid [0] => Array ( [tileID] => 1 [rotation] => 0 ) [1] => Array ( [tileID] => 1 [rotation] => 0 ) // Etc.. ) [1] => Array // etc.. etc.. ) ) I use this object to render out an isometric grid for my HTML5 Canvas game. I'm building a map editor and to put more tiles on the map, i'll have to add values to this json object. This is how I would do it in PHP: mapData[column][row] = array( 'tileID' => 1, 'rotation' => 0 ); So my question is, how do I achieve this with a JSON object in javascript? Thanks in advance! Nick Update I've ran into an error: can't convert undefined to object mapDataTiles[mouseY][mouseX] = { tileID: editorSelectedTile, rotation: 0 }; This is the code i use for clicking & then saving the new tile to the JSON object. At first I though that one of my parameters was 'undefined', so i logged those to the console but they came out perfectly.. // If there is already a tile placed on these coordinates if( mapDataTiles[mouseX] && mapDataTiles[mouseX][mouseY] ) { mapDataTiles[mouseX][mouseY]['tileID'] = editorSelectedTile; } // If there is no tile placed on these coordinates else { mapDataTiles[mouseX][mouseY] = { tileID: editorSelectedTile, rotation: 0 }; } My variables have the following values: MouseX: 5 MouseY: 17 tileID: 2 Also weird fact, that for some coordinates it does actually work and save new data to the array. mapDataTiles[mouseY][mouseX] = { tileID: editorSelectedTile, rotation: 0 };

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• Discovering a functional algorithm from a mutable one

  - by Garrett Rowe

  This isn't necessarily a Scala question, it's a design question that has to do with avoiding mutable state, functional thinking and that sort. It just happens that I'm using Scala. Given this set of requirements: Input comes from an essentially infinite stream of random numbers between 1 and 10 Final output is either SUCCEED or FAIL There can be multiple objects 'listening' to the stream at any particular time, and they can begin listening at different times so they all may have a different concept of the 'first' number; therefore listeners to the stream need to be decoupled from the stream itself. Pseudocode: if (first number == 1) SUCCEED else if (first number >= 9) FAIL else { first = first number rest = rest of stream for each (n in rest) { if (n == 1) FAIL else if (n == first) SUCCEED else continue } } Here is a possible mutable implementation: sealed trait Result case object Fail extends Result case object Succeed extends Result case object NoResult extends Result class StreamListener { private var target: Option[Int] = None def evaluate(n: Int): Result = target match { case None => if (n == 1) Succeed else if (n >= 9) Fail else { target = Some(n) NoResult } case Some(t) => if (n == t) Succeed else if (n == 1) Fail else NoResult } } This will work but smells to me. StreamListener.evaluate is not referentially transparent. And the use of the NoResult token just doesn't feel right. It does have the advantage though of being clear and easy to use/code. Besides there has to be a functional solution to this right? I've come up with 2 other possible options: Having evaluate return a (possibly new) StreamListener, but this means I would have to make Result a subtype of StreamListener which doesn't feel right. Letting evaluate take a Stream[Int] as a parameter and letting the StreamListener be in charge of consuming as much of the Stream as it needs to determine failure or success. The problem I see with this approach is that the class that registers the listeners should query each listener after each number is generated and take appropriate action immediately upon failure or success. With this approach, I don't see how that could happen since each listener is forcing evaluation of the Stream until it completes evaluation. There is no concept here of a single number generation. Is there any standard scala/fp idiom I'm overlooking here?

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• Android: Creating custom class of resources

  - by Sebastian

  Hi, R class on android has it's limitations. You can't use the resources dynamically for loading audio, pictures or whatever. If you wan't for example, load a set of audio files for a choosen object you can't do something like: R.raw."string-upon-choosen-object" I'm new to android and at least I didn't find how you could do that, depending on what objects are choosen or something more dynamic than that. So, I thought about making it dynamic with a little of memory overhead. But, I'm in doubt if it's worth it or just working different with external resources. The idea is this: Modify the ant build xml to execute my own task. This task, is a java program that parses the R.java file building a set of HashMaps with it's pair (key, value). I have done this manually and It's working good. So I need some experts voice about it. This is how I will manage the whole thing: Generate a base Application class, e.g. MainApplicationResources that builds up all the require methods and attributes. Then, you can access those methods invoking getApplication() and then the desired method. Something like this: package [packageName] import android.app.Application; import java.util.HashMap; public class MainActivityResources extends Application { private HashMap<String,Integer> [resNameObj1]; private HashMap<String,Integer> [resNameObj2]; ... private HashMap<String,Integer> [resNameObjN]; public MainActivityResources() { super(); [resNameObj1] = new HashMap<String,Integer>(); [resNameObj1].put("[resNameObj1_Key1]", new Integer([resNameObj1_Value1])); [resNameObj1].put("[resNameObj1_Key2]", new Integer([resNameObj1_Value2])); [resNameObj2] = new HashMap<String,Integer>(); [resNameObj2].put("[resNameObj2_Key1]", new Integer([resNameObj2_Value1])); [resNameObj2].put("[resNameObj2_Key2]", new Integer([resNameObj2_Value2])); ... [resNameObjN] = new HashMap<String,Integer>(); [resNameObjN].put("[resNameObjN_Key1]", new Integer([resNameObjN_Value1])); [resNameObjN].put("[resNameObjN_Key2]", new Integer([resNameObjN_Value2])); } public int get[ResNameObj1](String resourceName) { return [resNameObj1].get(resourceName).intValue(); } public int get[ResNameObj2](String resourceName) { return [resNameObj2].get(resourceName).intValue(); } ... public int get[ResNameObjN](String resourceName) { return [resNameObjN].get(resourceName).intValue(); } } The question is: Will I add too much memory use of the device? Is it worth it? Regards,

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• Consolidating coding styles: Funcs, private method, single method classes

  - by jdoig

  Hi all, We currently have 3 devs with, some, conflicting styles and I'm looking for a way to bring peace to the kingdom... The Coders: Foo 1: Likes to use Func's & Action's inside public methods. He uses actions to alias off lengthy method calls and Func's to perform simple tasks that can be expressed in 1 or 2 lines and will be used frequently through out the code Pros: The main body of his code is succinct and very readable, often with only one or 2 public methods per class and rarely any private methods. Cons: The start of methods contain blocks of lambda rich code that other developers don't enjoy reading; and, on occasion, can contain higher order functions that other dev's REALLY don't like reading. Foo 2: Likes to create a private method for (almost) everything the public method will have to do . Pros: Public methods remain small and readable (to all developers). Cons: Private methods are numerous. With private methods that call into other private methods, that call into... etc, etc. Making code hard to navigate. Foo 3: Likes to create a public class with a, single, public method for every, non-trivial, task that needs performing, then dependency inject them into other objects. Pros: Easily testable, easy to understand (one object, one responsibility). Cons: project gets littered by classes, opening multiple class files to understand what code does makes navigation awkward. It would be great to take the best of all these techniques... Foo-1 Has really nice, readable (almost dsl-like) code... for the most part, except for all the Action and Func lambda shenanigans bulked together at the start of a method. Foo-3 Has highly testable and extensible code that just feels a bit "belt-&-braces" for some solutions and has some code-navigation niggles (constantly hitting F12 in VS and opening 5 other .cs files to find out what a single method does). And Foo-2... Well I'm not sure I like anything about the one-huge .cs file with 2 public methods and 12 private ones, except for the fact it's easier for juniors to dig into. I admit I grossly over-simplified the explanations of those coding styles; but if any one knows of any patterns, practices or diplomatic-manoeuvres that can help unite our three developers (without just telling any of them to just "stop it!") that would be great. From a feasibility standpoint : Foo-1's style meets with the most resistance due to some developers finding lambda and/or Func's hard to read. Foo-2's style meets with a less resistance as it's just so easy to fall into. Foo-3's style requires the most forward thinking and is difficult to enforce when time is short. Any ideas on some coding styles or conventions that can make this work?

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• E4X in ActionScript help needed

  - by voipsecuritydigest.com

  Here is the XML How using E4X read values of nodes <status>??</status> and of node <invisible value="false"/> ? <?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" creationComplete="init()"> <fx:Declarations> <!-- Place non-visual elements (e.g., services, value objects) here --> </fx:Declarations> <fx:Script> <![CDATA[ var xml:XML = <iq type="result" id="ss-1"> <query status-min-ver="1" status-max="512" status-list-contents-max="5" status-list-max="3" xmlns="google:shared-status"> <status> ?? </status> <show> default </show> <status-list show="default"> <status> ?? </status> <status> ? </status> <status> ?? </status> </status-list> <status-list show="dnd"> <status> ?? </status> <status> dnd, i have bad mood </status> <status> showering </status> <status> ??_???¦ </status> <status> ? </status> </status-list> <invisible value="false"/> </query> </iq> public function init() { trace(xml.query.invisible.@value); } ]]> </fx:Script> </s:Application>

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• NSLinguisticTagger on the contents of an NSTextStorage- crashing bug

  - by Remy Porter

  I'm trying to use an NSLinguisticTagger to monitor the contents of an NSTextStorage and provide some contextual information based on what the user types. To that end, I have an OverlayManager object, which wires up this relationship: -(void) setView:(NSTextView*) view { _view = view; _layout = view.layoutManager; _storage = view.layoutManager.textStorage; //get the TextStorage from the view [_tagger setString:_storage.string]; //pull the string out, this grabs the mutable version [self registerForNotificationsOn:self->_storage]; //subscribe to the willProcessEditing notification } When an edit occurs, I make sure to trap it and notify the tagger (and yes, I know I'm being annoyingly inconsistent with member access, I'm rusty on Obj-C, I'll fix it later): - (void) textStorageWillProcessEditing:(NSNotification*) notification{ if ([self->_storage editedMask] & NSTextStorageEditedCharacters) { NSRange editedRange = [self->_storage editedRange]; NSUInteger delta = [self->_storage changeInLength]; [_tagger stringEditedInRange:editedRange changeInLength:delta]; //should notify the tagger of the changes [self highlightEdits:self]; } } The highlightEdits message delegates the job out to a pool of "Overlay" objects. Each contains a block of code similar to this: [tagger enumerateTagsInRange:range scheme:NSLinguisticTagSchemeLexicalClass options:0 usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop) { if (tag == PartOfSpeech) { [self applyHighlightToRange:tokenRange onStorage:storage]; } }]; And that's where the problem is- the enumerateTagsInRange method crashes out with a message: 2014-06-04 10:07:19.692 WritersEditor[40191:303] NSMutableRLEArray replaceObjectsInRange:withObject:length:: Out of bounds This problem doesn't occur if I don't link to the mutable copy of the underlying string and instead do a [[_storage string] copy], but obviously I don't want to copy the entire backing store every time I want to do tagging. This all should be happening in the main run loop, so I don't think this is a threading issue. The NSRange I'm enumerating tags on exists both in the NSTextStorage and in the NSLinguisticTagger's view of the string. It's not even the fact that the applyHighlightToRange call adds attributes to the string, because it crashes before even reaching that line. I attempted to build a test case around the problem, but can't replicate it in those situations: - (void) testEdit { NSAttributedString* str = [[NSMutableAttributedString alloc] initWithString:@"Quickly, this is a test."]; text = [[NSTextStorage alloc] initWithAttributedString:str]; NSArray* schemes = [NSLinguisticTagger availableTagSchemesForLanguage:@"en"]; tagger = [[NSLinguisticTagger alloc] initWithTagSchemes:schemes options:0]; [tagger setString:[text string]]; [text beginEditing]; [[text mutableString] appendString:@"T"]; NSRange edited = [text editedRange]; NSUInteger length = [text changeInLength]; [text endEditing]; [tagger stringEditedInRange:edited changeInLength:length]; [tagger enumerateTagsInRange:edited scheme:NSLinguisticTagSchemeLexicalClass options:0 usingBlock:^(NSString *tag, NSRange tokenRange, NSRange sentenceRange, BOOL *stop) { //doesn't matter, this should crash }]; } That code doesn't crash.

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• Snake game, can't add new rectangles?

  - by user1814358

  I had seen some problem on other forum, and i tried to solve them but unsuccesfully, now is too intersting for me and i just need to solve this for my ego... lol Main problem is when snake eat first food, snake added one rectangle, when snake eat second food nothings changed? When snake head position and food position are same, then i try to add another rectangle, i have list where i stored rectangles coordinates x and y. What do you think, how i can to solve this problem? I think that i'm so close, but my brain has stopped. :( code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace Zmijice { enum Kontrole { Desno,Levo,Gore,Dole,Stoj } public partial class Zmijice : Form { int koox; int kooy; private int x; private int y; private int c; private int b; private const int visina=20; //width private const int sirina=20; //height //private int m = 20; //private int n = 20; private List<int> SegmentX = new List<int>(); private List<int> SegmentY = new List<int>(); Random rnd = new Random(); private Kontrole Pozicija; public Zmijice() { InitializeComponent(); //slucajne pozicije pri startu x = rnd.Next(1, 20) * 20; y = rnd.Next(1, 20) * 20; c = rnd.Next(1, 20) * 20; b = rnd.Next(1, 20) * 20; Pozicija = Kontrole.Stoj; //stop on start } private void Tajmer_Tick(object sender, EventArgs e) { if (Pozicija == Kontrole.Stoj) { //none } if (Pozicija == Kontrole.Desno) { x += 20; } else if (Pozicija == Kontrole.Levo) { x -= 20; } else if (Pozicija == Kontrole.Gore) { y -= 20; } else if (Pozicija == Kontrole.Dole) { y += 20; } Invalidate(); } private void Zmijice_KeyDown(object sender, KeyEventArgs e) { if (e.KeyCode == Keys.Down) { Pozicija = Kontrole.Dole; } else if (e.KeyCode == Keys.Up) { Pozicija = Kontrole.Gore; } else if (e.KeyCode == Keys.Right) { Pozicija = Kontrole.Desno; } else if (e.KeyCode == Keys.Left) { Pozicija = Kontrole.Levo; } } private void Zmijice_Paint(object sender, PaintEventArgs e) { int counter = 1; //ako je pojela hranu if (x==c && y==b) { counter++; c = rnd.Next(1, 20); //nova pozicija hrrane c = c * 20; b = rnd.Next(1, 20); b = b * 20; //povecaj zmijicu SegmentX.Add(x); SegmentY.Add(y); //label1.Text = SegmentX.Count().ToString() + " " + SegmentY.Count().ToString(); //left if (Pozicija == Kontrole.Levo) { koox = x+20; kooy = y; } //right if (Pozicija == Kontrole.Desno) { koox = x-20; kooy = y; } //up if (Pozicija == Kontrole.Gore) { koox = x; kooy = y+20; } //down if (Pozicija == Kontrole.Dole) { koox = x; kooy = y-20; } } foreach (int k in SegmentX) { foreach (int l in SegmentY) { e.Graphics.FillRectangle(Brushes.Orange, koox, kooy, sirina, visina); } } koox = x; kooy = y; e.Graphics.FillRectangle(Brushes.DarkRed, x, y, sirina, visina); e.Graphics.FillRectangle(Brushes.Aqua, c, b, sirina, visina); } } }

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• How to avoid repetition when working with primitive types?

  - by I82Much

  I have the need to perform algorithms on various primitive types; the algorithm is essentially the same with the exception of which type the variables are. So for instance, /** * Determine if <code>value</code> is the bitwise OR of elements of <code>validValues</code> array. * For instance, our valid choices are 0001, 0010, and 1000. * We are given a value of 1001. This is valid because it can be made from * ORing together 0001 and 1000. * On the other hand, if we are given a value of 1111, this is invalid because * you cannot turn on the second bit from left by ORing together those 3 * valid values. */ public static boolean isValid(long value, long[] validValues) { for (long validOption : validValues) { value &= ~validOption; } return value != 0; } public static boolean isValid(int value, int[] validValues) { for (int validOption : validValues) { value &= ~validOption; } return value != 0; } How can I avoid this repetition? I know there's no way to genericize primitive arrays, so my hands seem tied. I have instances of primitive arrays and not boxed arrays of say Number objects, so I do not want to go that route either. I know there are a lot of questions about primitives with respect to arrays, autoboxing, etc., but I haven't seen it formulated in quite this way, and I haven't seen a decisive answer on how to interact with these arrays. I suppose I could do something like: public static<E extends Number> boolean isValid(E value, List<E> numbers) { long theValue = value.longValue(); for (Number validOption : numbers) { theValue &= ~validOption.longValue(); } return theValue != 0; } and then public static boolean isValid(long value, long[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } public static boolean isValid(int value, int[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } Is that really much better though? Any thoughts in this matter would be appreciated.

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• nhibernate cascade - problem with detached entities

  - by Chev

  I am going nuts here trying to resolve a cascading update/delete issue :-) I have a Parent Entity with a collection Child Entities. If I modify the list of Child entities in a detached Parent object, adding, deleting etc - I am not seeing the updates cascaded correctly to the Child collection. Mapping Files: <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="Domain" namespace="Domain"> <class name="Parent" table="Parent" > <id name="Id"> <generator class="guid.comb" /> </id> <version name="LastModified" unsaved-value="0" column="LastModified" /> <property name="Name" type="String" length="250" /> <bag name="ParentChildren" lazy="false" table="Parent_Children" cascade="all-delete-orphan" inverse="true"> <key column="ParentId" on-delete="cascade" /> <one-to-many class="ParentChildren" /> </bag> </class> <class name="ParentChildren" table="Parent_Children"> <id name="Id"> <generator class="guid.comb" /> </id> <version name="LastModified" unsaved-value="0" column="LastModified" /> <many-to-one name="Parent" class="Parent" column="ParentId" lazy="false" not-null="true" /> </class> </hibernate-mapping> Test [Test] public void Test() { Guid id; int lastModified; // add a child into 1st session then detach using(ISession session = Store.Local.Get<ISessionFactory>("SessionFactory").OpenSession()) { Console.Out.WriteLine("Selecting..."); Parent parent = (Parent) session.Get(typeof (Parent), new Guid("4bef7acb-bdae-4dd0-ba1e-9c7500f29d47")); id = parent.Id; lastModified = parent.LastModified + 1; // ensure the detached version used later is equal to the persisted version Console.Out.WriteLine("Adding Child..."); Child child = (from c in session.Linq<Child>() select c).First(); parent.AddChild(child, 0m); session.Flush(); session.Dispose(); // not needed i know } // attach a parent, then save with no Children using (ISession session = Store.Local.Get<ISessionFactory>("SessionFactory").OpenSession()) { Parent parent = new Parent("Test"); parent.Id = id; parent.LastModified = lastModified; session.Update(parent); session.Flush(); } } I assume that the fact that the product has been updated to have no children in its collection - the children would be deleted in the Parent_Child table. The problems seems to be something to do with attaching the Product to the new session? As the cascade is set to all-delete-orphan I assume that changes to the collection would be propagated to the relevant entities/tables? In this case deletes? What am I missing here? C

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• Problems manipulating strings through a stdcall to a dll

  - by ibiza

  I need to create a C++ dll that will be called from another program through stdcall. What is needed : the caller program will pass an array of string to the dll and the dll should change the string values in the array. The caller program will then continue to work with these string values that came from the dll. I made a simple test project and I am obviously missing something... Here is my test C++ dll : #ifndef _DLL_H_ #define _DLL_H_ #include <string> #include <iostream> struct strStruct { int len; char* string; }; __declspec (dllexport) int __stdcall TestFunction(strStruct* s) { std::cout << "Just got in dll" << std::endl; std::cout << s[0].string << std::endl; //////std::cout << s[1].string << std::endl; /* char str1[] = "foo"; strcpy(s[0].string, str1); s[0].len = 3; char str2[] = "foobar"; strcpy(s[1].string, str2); s[1].len = 6; */ //std::cout << s[0].string << std::endl; //std::cout << s[1].string << std::endl; std::cout << "Getting out of dll" << std::endl; return 1; } #endif and here is a simple C# program that I am using to test my test dll : using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace TestStr { class Program { [DllImport("TestStrLib.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)] public static extern int TestFunction(string[] s); static void Main(string[] args) { string[] test = new string[2] { "a1a1a1a1a1", "b2b2b2b2b2" }; Console.WriteLine(test[0]); Console.WriteLine(test[1]); TestFunction(test); Console.WriteLine(test[0]); Console.WriteLine(test[1]); Console.ReadLine(); } } } And here is the output produced : a1a1a1a1a1 b2b2b2b2b2 Just got in dll b2b2b2b2b2 Getting out of dll a1a1a1a1a1 b2b2b2b2b2 I have some questions : 1) Why is it outputting the element in the second position of the array rather than in the first position?? 2) If I uncomment the line commented with ////// in the dll file, the program crashes. Why? 3) Obviously I wanted to do more things in the dll (the parts in /* */) than what it does right now, but I am blocked by the first 2 questions... Thanks for all your help

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• How do you prevent IDisposable from spreading to all your classes?

  - by GrahamS

  Start with these simple classes... Let's say I have a simple set of classes like this: class Bus { Driver busDriver = new Driver(); } class Driver { Shoe[] shoes = { new Shoe(), new Shoe() }; } class Shoe { Shoelace lace = new Shoelace(); } class Shoelace { bool tied = false; } A Bus has a Driver, the Driver has two Shoes, each Shoe has a Shoelace. All very silly. Add an IDisposable object to Shoelace Later I decide that some operation on the Shoelace could be multi-threaded, so I add an EventWaitHandle for the threads to communicate with. So Shoelace now looks like this: class Shoelace { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; // ... other stuff .. } Implement IDisposable on Shoelace Buit now FxCop will complain: "Implement IDisposable on 'Shoelace' because it creates members of the following IDisposable types: 'EventWaitHandle'." Okay, I implement IDisposable on Shoelace and my neat little class becomes this horrible mess: class Shoelace : IDisposable { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; private bool disposed = false; public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } ~Shoelace() { Dispose(false); } protected virtual void Dispose(bool disposing) { if (!this.disposed) { if (disposing) { if (waitHandle != null) { waitHandle.Close(); waitHandle = null; } } // No unmanaged resources to release otherwise they'd go here. } disposed = true; } } Or (as pointed out by commenters) since Shoelace itself has no unmanaged resources, I might use the simpler dispose implementation without needing the Dispose(bool) and Destructor: class Shoelace : IDisposable { private AutoResetEvent waitHandle = new AutoResetEvent(false); bool tied = false; public void Dispose() { if (waitHandle != null) { waitHandle.Close(); waitHandle = null; } GC.SuppressFinalize(this); } } Watch in horror as IDisposable spreads Right that's that fixed. But now FxCop will complain that Shoe creates a Shoelace, so Shoe must be IDisposable too. And Driver creates Shoe so Driver must be IDisposable. and Bus creates Driver so Bus must be IDisposable and so on. Suddenly my small change to Shoelace is causing me a lot of work and my boss is wondering why I need to checkout Bus to make a change to Shoelace. The Question How do you prevent this spread of IDisposable, but still ensure that your unmanaged objects are properly disposed?

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• When Clearing an ObservableCollection, There are No Items in e.OldItems

  - by cplotts

  I have something here that is really catching me off guard. I have an ObservableCollection of T that is filled with items. I also have an event handler attached to the CollectionChanged event. When you Clear the collection it causes an CollectionChanged event with e.Action set to NotifyCollectionChangedAction.Reset. Ok, that's normal. But what is weird is that neither e.OldItems or e.NewItems has anything in it. I would expect e.OldItems to be filled with all items that were removed from the collection. Has anyone else seen this? And if so, how have they gotten around it? Some background: I am using the CollectionChanged event to attach and detach from another event and thus if I don't get any items in e.OldItems ... I won't be able to detach from that event. CLARIFICATION: I do know that the documentation doesn't outright state that it has to behave this way. But for every other action, it is notifying me of what it has done. So, my assumption is that it would tell me ... in the case of Clear/Reset as well. Below is the sample code if you wish to reproduce it yourself. First off the xaml: <Window x:Class="ObservableCollection.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300" > <StackPanel> <Button x:Name="addButton" Content="Add" Width="100" Height="25" Margin="10" Click="addButton_Click"/> <Button x:Name="moveButton" Content="Move" Width="100" Height="25" Margin="10" Click="moveButton_Click"/> <Button x:Name="removeButton" Content="Remove" Width="100" Height="25" Margin="10" Click="removeButton_Click"/> <Button x:Name="replaceButton" Content="Replace" Width="100" Height="25" Margin="10" Click="replaceButton_Click"/> <Button x:Name="resetButton" Content="Reset" Width="100" Height="25" Margin="10" Click="resetButton_Click"/> </StackPanel> </Window> Next, the code behind: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Collections.ObjectModel; namespace ObservableCollection { /// <summary> /// Interaction logic for Window1.xaml /// </summary> public partial class Window1 : Window { public Window1() { InitializeComponent(); _integerObservableCollection.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(_integerObservableCollection_CollectionChanged); } private void _integerObservableCollection_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) { switch (e.Action) { case System.Collections.Specialized.NotifyCollectionChangedAction.Add: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Move: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Remove: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Replace: break; case System.Collections.Specialized.NotifyCollectionChangedAction.Reset: break; default: break; } } private void addButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.Add(25); } private void moveButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.Move(0, 19); } private void removeButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.RemoveAt(0); } private void replaceButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection[0] = 50; } private void resetButton_Click(object sender, RoutedEventArgs e) { _integerObservableCollection.Clear(); } private ObservableCollection<int> _integerObservableCollection = new ObservableCollection<int> { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 }; } }

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• SQL: GROUP BY after JOIN without overriding rows?

  - by krismeld

  I have a table of basketball leagues, a table af teams and a table of players like this: LEAGUES ID | NAME | ------------------ 1 | NBA | 2 | ABA | TEAMS: ID | NAME | LEAGUE_ID ------------------------------ 20 | BULLS | 1 21 | KNICKS | 2 PLAYERS: ID | TEAM_ID | FIRST_NAME | LAST_NAME | --------------------------------------------- 1 | 21 | John | Starks | 2 | 21 | Patrick | Ewing | Given a League ID, I would like to retrieve all the players' names and their team ID from all the teams in that league, so I do this: SELECT t.id AS team_id, p.id AS player_id, p.first_name, p.last_name FROM teams AS t JOIN players AS p ON p.team_id = t.id WHERE t.league_id = 1 which returns: [0] => stdClass Object ( [team_id] => 21 [player_id] => 1 [first_name] => John [last_name] => Starks ) [1] => stdClass Object ( [team_id] => 21 [player_id] => 2 [first_name] => Patrick [last_name] => Ewing ) + around 500 more objects... Since I will use this result to populate a dropdown menu for each team containing each team's list of players, I would like to group my result by team ID, so the loop to create these dropdowns will only have to cycle through each team ID instead of all 500+ players each time. But when I use the GROUP BY like this: SELECT t.id AS team_id, p.id AS player_id, p.first_name, p.last_name FROM teams AS t JOIN players AS p ON p.team_id = t.id WHERE t.league_id = 1 GROUP BY t.id it only returns one player from each team like this, overriding all the other players on the same team because of the use of the same column names. [0] => stdClass Object ( [team_id] => 21 [player_id] => 2 [first_name] => Patrick [last_name] => Ewing ) [1] => stdClass Object ( [team_id] => 22 [player_id] => 31 [first_name] => Shawn [last_name] => Kemp ) etc... I would like to return something like this: [0] => stdClass Object ( [team_id] => 2 [player_id1] => 1 [first_name1] => John [last_name1] => Starks [player_id2] => 2 [first_name2] => Patrick [last_name2] => Ewing +10 more players from this team... ) +25 more teams... Is it possible somehow?

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• C++ Virtual Constructor, without clone()

  - by Julien L.

  I want to perform "deep copies" of an STL container of pointers to polymorphic classes. I know about the Prototype design pattern, implemented by means of the Virtual Ctor Idiom, as explained in the C++ FAQ Lite, Item 20.8. It is simple and straightforward: struct ABC // Abstract Base Class { virtual ~ABC() {} virtual ABC * clone() = 0; }; struct D1 : public ABC { virtual D1 * clone() { return new D1( *this ); } // Covariant Return Type }; A deep copy is then: for( i = 0; i < oldVector.size(); ++i ) newVector.push_back( oldVector[i]->clone() ); Drawbacks As Andrei Alexandrescu states it: The clone() implementation must follow the same pattern in all derived classes; in spite of its repetitive structure, there is no reasonable way to automate defining the clone() member function (beyond macros, that is). Moreover, clients of ABC can possibly do something bad. (I mean, nothing prevents clients to do something bad, so, it will happen.) Better design? My question is: is there another way to make an abstract base class clonable without requiring derived classes to write clone-related code? (Helper class? Templates?) Following is my context. Hopefully, it will help understanding my question. I am designing a class hierarchy to perform operations on a class Image: struct ImgOp { virtual ~ImgOp() {} bool run( Image & ) = 0; }; Image operations are user-defined: clients of the class hierarchy will implement their own classes derived from ImgOp: struct CheckImageSize : public ImgOp { std::size_t w, h; bool run( Image &i ) { return w==i.width() && h==i.height(); } }; struct CheckImageResolution; struct RotateImage; ... Multiple operations can be performed sequentially on an image: bool do_operations( std::vector< ImgOp* > v, Image &i ) { std::for_each( v.begin(), v.end(), /* bind2nd(mem_fun(&ImgOp::run), i ...) don't remember syntax */ ); } int main( ... ) { std::vector< ImgOp* > v; v.push_back( new CheckImageSize ); v.push_back( new CheckImageResolution ); v.push_back( new RotateImage ); Image i; do_operations( v, i ); } If there are multiple images, the set can be split and shared over several threads. To ensure "thread-safety", each thread must have its own copy of all operation objects contained in v -- v becomes a prototype to be deep copied in each thread.

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• asp.net mvc How to test controllers correctly

  - by Simon G

  Hi, I'm having difficulty testing controllers. Original my controller for testing looked something like this: SomethingController CreateSomethingController() { var somethingData = FakeSomethingData.CreateFakeData(); var fakeRepository = FakeRepository.Create(); var controller = new SomethingController(fakeRepository); return controller; } This works fine for the majority of testing until I got the Request.IsAjaxRequest() part of code. So then I had to mock up the HttpContext and HttpRequestBase. So my code then changed to look like: public class FakeHttpContext : HttpContextBase { bool _isAjaxRequest; public FakeHttpContext( bool isAjaxRequest = false ) { _isAjaxRequest = isAjaxRequest; } public override HttpRequestBase Request { get { string ajaxRequestHeader = ""; if ( _isAjaxRequest ) ajaxRequestHeader = "XMLHttpRequest"; var request = new Mock<HttpRequestBase>(); request.SetupGet( x => x.Headers ).Returns( new WebHeaderCollection { {"X-Requested-With", ajaxRequestHeader} } ); request.SetupGet( x => x["X-Requested-With"] ).Returns( ajaxRequestHeader ); return request.Object; } } private IPrincipal _user; public override IPrincipal User { get { if ( _user == null ) { _user = new FakePrincipal(); } return _user; } set { _user = value; } } } SomethingController CreateSomethingController() { var somethingData = FakeSomethingData.CreateFakeData(); var fakeRepository = FakeRepository.Create(); var controller = new SomethingController(fakeRepository); ControllerContext controllerContext = new ControllerContext( new FakeHttpContext( isAjaxRequest ), new RouteData(), controller ); controller.ControllerContext = controllerContext; return controller; } Now its got to that stage in my controller where I call Url.Route and Url is null. So it looks like I need to start mocking up routes for my controller. I seem to be spending more time googling on how to fake/mock objects and then debugging to make sure my fakes are correct than actual writing the test code. Is there an easier way in to test a controller? I've looked at the TestControllerBuilder from MvcContrib which helps with some of the issues but doesn't seem to do everything. Is there anything else available that will do the job and will let me concentrate on writing the tests rather than writing mocks? Thanks

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• AngularJS service returning promise unit test gives error No more request expected

  - by softweave

  I want to test a service (Bar) that invokes another service (Foo) and returns a promise. The test is currently failing with this error: Error: Unexpected request: GET foo.json No more request expected Here are the service definitions: // Foo service returns new objects having get function returning a promise angular.module('foo', []). factory('Foo', ['$http', function ($http) { function FooFactory(config) { var Foo = function (config) { angular.extend(this, config); }; Foo.prototype = { get: function (url, params, successFn, errorFn) { successFn = successFn || function (response) {}; errorFn = errorFn || function (response) {}; return $http.get(url, {}).then(successFn, errorFn); } }; return new Foo(config); }; return FooFactory; }]); // Bar service uses Foo service angular.module('bar', ['foo']). factory('Bar', ['Foo', function (Foo) { var foo = Foo(); return { getCurrentTime: function () { return foo.get('foo.json', {}, function (response) { return Date.parse(response.data.now); }); } }; }]); Here is my current test: 'use strict'; describe('bar tests', function () { var currentTime, currentTimeInMs, $q, $rootScope, mockFoo, mockFooFactory, Foo, Bar, now; currentTime = "March 26, 2014 13:10 UTC"; currentTimeInMs = Date.parse(currentTime); beforeEach(function () { // stub out enough of Foo to satisfy Bar service: // create mock object with function get: function(url, params, successFn, errorFn) // that promises to return a response with this property // { data: { now: "March 26, 2014 13:10 UTC" }}) mockFoo = { get: function (url, params, successFn, errorFn) { successFn = successFn || function (response) {}; errorFn = errorFn || function (response) {}; // setup deferred promise var deferred = $q.defer(); deferred.resolve({data: { now: currentTime }}); return (deferred.promise).then(successFn, errorFn); } }; // create mock Foo service mockFooFactory = function(config) { return mockFoo; }; module(function ($provide) { $provide.value('Foo', mockFooFactory); }); module('bar'); inject(function (_$q_, _$rootScope_, _Foo_, _Bar_) { $q = _$q_; $rootScope = _$rootScope_; Foo = _Foo_; Bar = _Bar_; }); }); it('getCurrentTime should return currentTimeInMs', function () { Bar.getCurrentTime().then(function (serverCurrentTime) { now = serverCurrentTime; }); $rootScope.$apply(); // resolve Bar promise expect(now).toEqual(currentTimeInMs); }); }); The error is being thrown at $rootScope.$apply(). I also tried using $rootScope.$digest(), but it gives the same error. Thanks in advance for any insight you can give me.

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• How to perform duplicate key validation using entlib (or DataAnnotations), MVC, and Repository pattern

  - by olivehour

  I have a set of ASP.NET 4 projects that culminate in an MVC (3 RC2) app. The solution uses Unity and EntLib Validation for cross-cutting dependency injection and validation. Both are working great for injecting repository and service layer implementations. However, I can't figure out how to do duplicate key validation. For example, when a user registers, we want to make sure they don't pick a UserID that someone else is already using. For this type of validation, the validating object must have a repository reference... or some other way to get an IQueryable / IEnumerable reference to check against other rows already in the DB. What I have is a UserMetadata class that has all of the property setters and getters for a user, along with all of the appropriate DataAnnotations and EntLib Validation attributes. There is also a UserEntity class implemented using EF4 POCO Entity Generator templates. The UserEntity depends on UserMetadata, because it has a MetadataTypeAttribute. I also have a UserViewModel class that has the same exact MetadataType attribute. This way, I can apply the same validation rules, via attributes, to both the entity and viewmodel. There are no concrete references to the Repository classes whatsoever. All repositories are injected using Unity. There is also a service layer that gets dependency injection. In the MVC project, service layer implementation classes are injected into the Controller classes (the controller classes only contain service layer interface references). Unity then injects the Repository implementations into the service layer classes (service classes also only contain interface references). I've experimented with the DataAnnotations CustomValidationAttribute in the metadata class. The problem with this is the validation method must be static, and the method cannot instantiate a repository implementation directly. My repository interface is IRepository, and I have only one single repository implementation class defined as EntityRepository for all domain objects. To instantiate a repository explicitly I would need to say new EntityRepository(), which would result in a circular dependency graph: UserMetadata [depends on] DuplicateUserIDValidator [depends on] UserEntity [depends on] UserMetadata. I've also tried creating a custom EntLib Validator along with a custom validation attribute. Here I don't have the same problem with a static method. I think I could get this to work if I could just figure out how to make Unity inject my EntityRepository into the validator class... which I can't. Right now, all of the validation code is in my Metadata class library, since that's where the custom validation attribute would go. Any ideas on how to perform validations that need to check against the current repository state? Can Unity be used to inject a dependency into a lower-layer class library?

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• Should I add try/catch around when casting on an attribute of JSP implicit object?

  - by Michael Mao

  Hi all: Basically what I mean is like this: List<String[]> routes = (List<String[]>)application.getAttribute("routes"); For the above code, it tries to get an attribute named "routes" from the JSP implicit object - application. But as everyone knows, after this line of code, routes may very well contains a null - which means this application hasn't got an attribute named "routes". Is this "casting on null" good programming practice in Java or not? Basically I try to avoid exceptions such as java.io.InvalidCastException I reckon things like this are more as "heritage" of Java 1.4 when generic types were not introduced to this language. So I guess everything stored in application attributes as Objects (Similar to traditional ArrayList). And when you do "downcast", there might be invalid casts. What would you do in this case? Update: Just found that although in the implicit object application I did store a List of String arrays, when I do this : List<double[]> routes = (List<double[]>)application.getAttribute("routes"); It doesn't produce any error... And I felt not comfortable already... And even with this code: out.print(routes.get(0)); It does print out something strange : [Ljava.lang.String;@18b352f Am I printing a "pointer to String"? I can finally get an exception like this: out.print(routes.get(0)[1]); with error : java.lang.ClassCastException: [Ljava.lang.String; Because it was me to add the application attribute, I know which type should it be cast to. I feel this is not "good enough", what if I forget the exact type? I know there are still some cases where this sort of thing would happen, such as in JSP/Servlet when you do casting on session attributes. Is there a better way to do this? Before you say:"OMG, why you don't use Servlets???", I should justify my reason as this: - because my uni sucks, its server can only work with Servlets generated by JSP, and I don't really want to learn how to fix issues like that. look at my previous question on this , and this is uni homework, so I've got no other choice, forget all about war, WEB-INF,etc, but "code everything directly into JSP" - because the professors do that too. :)

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• Cannot decode complete cipher list in .NET SslStream handshake.

  - by karmasponge

  While attempting to move from a 'C' based SSL implementation to C# using the .NET SslStream and we have run into what look like cipher compatibility issues with the .NET SslStream and a AS400 machine we are trying to connect to (which worked previously). When we call SslStream.AuthenticateAsClient it is sending the following: 16 03 00 00 37 01 00 00 33 03 00 4d 2c 00 ee 99 4e 0c 5d 83 14 77 78 5c 0f d3 8f 8b d5 e6 b8 cd 61 0f 29 08 ab 75 03 f7 fa 7d 70 00 00 0c 00 05 00 0a 00 13 00 04 00 02 00 ff 01 00 Which decodes as (based on http://www.mozilla.org/projects/security/pki/nss/ssl/draft302.txt) [16] Record Type [03 00] SSL Version [00 37] Body length [01] SSL3_MT_CLIENT_HELLO [00 00 33] Length (51 bytes) [03 00] Version number = 768 [4d 2c 00 ee] 4 Bytes unix time [… ] 28 Bytes random number [00] Session number [00 0c] 12 bytes (2 * 6 Cyphers)? [00 05, 00 0a, 00 13, 00 04, 00 02, 00 ff] - [RC4, PBE-MD5-DES, RSA, MD5, PKCS, ???] [01 00] Null compression method The as400 server responds back with: 15 03 00 00 02 02 28 [15] SSL3_RT_ALERT [03 00] SSL Version [00 02] Body Length (2 Bytes) [02 28] 2 = SSL3_RT_FATAL, 40 = SSL3_AD_HANDSHAKE_FAILURE I'm specifically looking to decode the '00 FF' at the end of the cyphers. Have I decoded it correctly? What does, if anything, '00 FF' decode too? I am using the following code to test/reproduce: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net.Sockets; using System.Net.Security; using System.Security.Authentication; using System.IO; using System.Diagnostics; using System.Security.Cryptography.X509Certificates; namespace TestSslStreamApp { class DebugStream : Stream { private Stream AggregatedStream { get; set; } public DebugStream(Stream stream) { AggregatedStream = stream; } public override bool CanRead { get { return AggregatedStream.CanRead; } } public override bool CanSeek { get { return AggregatedStream.CanSeek; } } public override bool CanWrite { get { return AggregatedStream.CanWrite; } } public override void Flush() { AggregatedStream.Flush(); } public override long Length { get { return AggregatedStream.Length; } } public override long Position { get { return AggregatedStream.Position; } set { AggregatedStream.Position = value; } } public override int Read(byte[] buffer, int offset, int count) { int bytesRead = AggregatedStream.Read(buffer, offset, count); return bytesRead; } public override long Seek(long offset, SeekOrigin origin) { return AggregatedStream.Seek(offset, origin); } public override void SetLength(long value) { AggregatedStream.SetLength(value); } public override void Write(byte[] buffer, int offset, int count) { AggregatedStream.Write(buffer, offset, count); } } class Program { static void Main(string[] args) { const string HostName = "as400"; TcpClient tcpClient = new TcpClient(HostName, 992); SslStream sslStream = new SslStream(new DebugStream(tcpClient.GetStream()), false, null, null, EncryptionPolicy.AllowNoEncryption); sslStream.AuthenticateAsClient(HostName, null, SslProtocols.Ssl3, false); } } }

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• CoreData : App crashes when deleting last instance created

  - by Leo

  Hello, I have a 2 tabs application. In the first one, I'm creating objects of the "Sample" and "SampleList" entities. Each sampleList contains an ID and a set of samples. Each sample contains a date and temperature property. In the second tab, I'm displaying my data in a tableView. I implemented the - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath method in order to delete SampleLists. In my xcdatamodel the delete rule for my relationship between SampleList and Sample is Cascade. My problem is that when I try to delete SampleList I just created, the app crashes and I receive a EXC_BAD_ACCESS signal. If I restart it, then I'm able to delete "old" sampleList without any problems. Earlier, I had the following problem : I couldn't display the the sampleLists I created since I launched the app, because it crashed too. I received also the EXC_BAD_ACCESS signal. Actually, it seemed that the date of the last sample created of the set was nil. If I am not releasing the NSDate I'm using to set the sample's date, I don't have this problem anymore... If anyone could help me to find out what could cause my troubles it would be great !! Here is the method I'm using to create new instances : SampleList *newSampleList = (SampleList *)[NSEntityDescription insertNewObjectForEntityForName:@"SampleList" inManagedObjectContext:managedObjectContext]; [newSampleList setPatchID:patchID]; NSMutableSet *newSampleSet = [[NSMutableSet alloc] init]; NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]; for (int i = 0; i < [byteArray count]; i=i+4, sampleCount++) { NSDateComponents *comps = [[NSDateComponents alloc] init]; [comps setYear:year]; [comps setMonth:month]; [comps setDay:day]; [comps setHour:hours]; [comps setMinute:minutes]; NSDate *sampleDate = [gregorian dateFromComponents:comps]; Sample *newSample = (Sample *)[NSEntityDescription insertNewObjectForEntityForName:@"Sample" inManagedObjectContext:managedObjectContext]; [newSample setSampleDate:sampleDate]; [newSample setSampleTemperature:[NSNumber numberWithInt:temperature]]; [newSampleSet addObject:newSample]; [comps release]; //[sampleDate release]; } [newSampleList setSampleSet:newSampleSet]; // [newSampleSet release]; NSError *error; if (![managedObjectContext save:&error]) { NSLog(@"Could not Save the context !!"); } [gregorian release];

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• Java program has errors, 80 lines of code

  - by user2961687

  I have a problem with a program. It contains a lot of errors in Eclipse. Sorry for my english and thank you in advance. Here is the task: I. Declare a class that contains private fields Jam: String taste, double weight Create constructors containing variables as parameters: (String taste, double weight), (double weight), (String taste). Parameters constructors should initialize class fields. In case the constructor does not provide the necessary parameter, it must be assumed that the field taste must have the value "No Name" and weight - 100.0. Introduce the use of all constructors creating objects that represent three kinds of jams. Note: it must be assumed that the only constructor with two parameters can be assigned to fields of the class. Declare a class Jar that contains the field Jam jam, a dedicated constructor initiating all declared fields and methods: open close isItOpen Next, create an object of class Jar and fill it with the selected type of jam, operations repeat for all the kinds of jams. This is my code this far: public class App { public static void main(String[] args) { Jam strawberry = new Jam("strawberry", 20.45); Jam raspberry = new Jam(40.50); Jam peach = new Jam("peach"); Jar jar_1 = new Jar(); Jar jar_2 = new Jar(); Jar jar_3 = new Jar(); jar_1.open(); jar_1.fillIn(strawberry); jar_2.fillIn(peach); jar_3.fillIn(raspberry); } } class Jam { String taste; double weight; public Jam(String taste, double weight) { this.taste = taste; this.weight = weight; } public Jam(double weight) { this.taste = "No name"; this.weight = weight; } public Jam(String taste) { this.taste = taste; this.weight = 100.0; } } class Jar { public Jam Jam = new Jam(); private String state_jar; public Jar() { Jam.weight = 0; Jam.taste = ""; state_jar = "closed"; } public static String open() { state_jar = open; return state_jar; } public static String close() { state_jar = "closed"; return state_jar; } public static boolean isItOpen() { return state_jar; } public void fillIn(Jam jam) { if (isItOpen == false) open(); this.Jam.weight = jam.weight; this.Jam.taste = jam.taste; this.Jam.close(); } }

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• Generic linked list in c++

  - by itsaboy

  I have been struggling for too long a time now with a rather simple question about how to create a generic linked list in c++. The list should be able contain several types of structs, but each list will only contain one type of struct. The problem arises when I want to implement the getNode() function [see below], because then I have to specify which of the structs it should return. I have tried to substitute the structs with classes, where the getNode function returns a base class that is inherited by all the other classes, but it still does not do the trick, since the compiler does not allow the getNode function to return anything but the base class then. So here is some code snippet: typedef struct struct1 { int param1; (...) } struct1; typedef struct struct2 { double param1; (...) } struct2; typedef struct node { struct1 data; node* link; } node; class LinkedList { public: node *first; int nbrOfNodes; LinkedList(); void addNode(struct1); struct1 getNode(); bool isEmpty(); }; LinkedList::LinkedList() { first = NULL; nbrOfNodes = 0; } void LinkedList::addNode(struct1 newData) { if (nbrOfNodes == 0) { first = new node; first->data = newData; } else { node *it = first; for (int i = 0; i < nbrOfNodes; i++) { it = it->link; } node *newNode = new node; newNode->data = newData; it->link = newNode; } nbrOfNodes++; } bool LinkedList::isEmpty() { return !nbrOfNodes; } struct1 LinkedList::getNode() { param1 returnData = first->data; node* deleteNode = first; nbrOfNodes--; if (nbrOfNodes) first = deleteNode->link; delete deleteNode; return returnData; } So the question, put in one sentence, is as follows: How do I adjust the above linked list class so that it can also be used for struct2, without having to create a new almost identical list class for struct2 objects? As I said above, each instance of LinkedList will only deal with either struct1 or struct2. Grateful for hints or help

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• Copying metadata over a database link in Oracle 10g

  - by Tunde

  Thanks in advance for your help experts. I want to be able to copy over database objects from database A into database B with a procedure created on database B. I created a database link between the two and have tweaked the get_ddl function of the dbms_metadata to look like this: create or replace function GetDDL ( p_name in MetaDataPkg.t_string p_type in MetaDataPkg.t_string ) return MetaDataPkg.t_longstring is -- clob v_clob clob; -- array of long strings c_SYSPrefix constant char(4) := 'SYS_'; c_doublequote constant char(1) := '"'; v_longstrings metadatapkg.t_arraylongstring; v_schema metadatapkg.t_string; v_fullength pls_integer := 0; v_offset pls_integer := 0; v_length pls_integer := 0; begin SELECT DISTINCT OWNER INTO v_schema FROM all_objects@ENTORA where object_name = upper(p_name); -- get DDL v_clob := dbms_metadata.get_ddl(p_type, upper(p_name), upper(v_schema)); -- get CLOB length v_fullength := dbms_lob.GetLength(v_clob); for nIndex in 1..ceil(v_fullength / 32767) loop v_offset := v_length + 1; v_length := least(v_fullength - (nIndex - 1) * 32767, 32767); dbms_lob.read(v_clob, v_length, v_offset, v_longstrings(nIndex)); -- Remove table’s owner from DDL string: v_longstrings(nIndex) := replace( v_longstrings(nIndex), c_doublequote || user || c_doublequote || '.', '' ); -- Remove the following from DDL string: -- 1) "new line" characters (chr(10)) -- 2) leading and trailing spaces v_longstrings(nIndex) := ltrim(rtrim(replace(v_longstrings(nIndex), chr(10), ''))); end loop; -- close CLOB if (dbms_lob.isOpen(v_clob) > 0) then dbms_lob.close(v_clob); end if; return v_longstrings(1); end GetDDL; so as to remove the schema prefix that usually comes with metadata. I get a null value whenever I run this function over the database link with the following queries. select getddl( 'TABLE', 'TABLE1') from user_tables@ENTORA where table_name = 'TABLE1'; select getddl( 'TABLE', 'TABLE1') from dual@ENTORA; t_string is varchar2(30) t_longstring is varchar2(32767) and type t_ArrayLongString is table of t_longstring I would really appreciate it if any one could help. Many thanks.

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• AsyncPostBackTrigger Just flashing/flicking the UpdatePanel but not updating it

  - by Pankaj

  I am trying UpdatePanel & AsyncPostBackTrigger on master pages through find control method but problem is when I click on button (UpdateButton) It just flash/flick (No Postback) the UpdatePanle but still it don't update or refresh the gridview (images) inside the updatePanel. I have placed script Manger on the master page & an AJAX Update panel in a ContentPlaceHolder in the child page. Also, in another ContentPlaceholder there is an asp button (outside of the UpdatePanel). I want to refresh/reload the AJAX UpdatePanel with this asp button. Thanks for suggestions. Child Page Code :- protected void Page_Load(object sender, EventArgs e) { ScriptManager ScriptManager1 = (ScriptManager)Master.FindControl("ScriptManager1"); ContentPlaceHolder cph = (ContentPlaceHolder)Master.FindControl("cp_Button"); Button btnRefresh = (Button)cph.FindControl("btnRefresh"); ScriptManager1.RegisterAsyncPostBackControl(btnRefresh); } protected void btnRefresh_Click(object sender, EventArgs e) { UpdatePanel1.Update(); } <%@ Page Title="" Language="C#" MasterPageFile="~/InnerMaster.master" AutoEventWireup="true" CodeFile="A.aspx.cs" Inherits="A" Async="true" %> <asp:Content ID="Content3" ContentPlaceHolderID="MainContent" Runat="Server"> <asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Conditional" runat="server"> <ContentTemplate> <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="id" DataSourceID="SqlDataSource1"> <Columns> <asp:TemplateField> <ItemTemplate> <asp:Image ID="img12" runat="server" Width="650px" Height="600" ToolTip="A" ImageUrl='<%# Page.ResolveUrl(string.Format("~/Cli/{0}", Eval("image"))) %>' /> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </ContentTemplate> </asp:UpdatePanel> </asp:Content> <asp:Content ID="Content4" ContentPlaceHolderID="cp_Button" Runat="Server"> <asp:Button ID ="btnRefresh" runat="server" onclick="btnRefresh_Click" Height="34" Width="110" Text="More Images" /> </asp:Content> Hi updated code :- Now on click event whole pages is refreshed. using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; namespace EProxy { public class EventProxy : Control, IPostBackEventHandler { public EventProxy() { } public void RaisePostBackEvent(string eventArgument) { } public event EventHandler<EventArgs> EventProxied; protected virtual void OnEventProxy(EventArgs e) { if (this.EventProxied != null) { this.EventProxied(this, e); } } public void ProxyEvent(EventArgs e) { OnEventProxy(e); } } } On Master Page Code (btn click):- protected void btnRefresh_Click(object sender, EventArgs e) { ContentPlaceHolder cph = (ContentPlaceHolder)this.FindControl("MainContent"); EventProxy eventProxy = (EventProxy)cph.FindControl("ProxyControl") as EventProxy; eventProxy.ProxyEvent(e); } Web Config :- <pages maintainScrollPositionOnPostBack="true" enableViewStateMac="true"> <controls> <add tagPrefix="it" namespace="EProxy" assembly="App_Code"/> </controls> </pages>

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