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• Strange thing about .NET 4.0 filesystem enumeration functionality

  - by codymanix

  I just read a page of "Whats new .NET Framework 4.0". I have trouble understanding the last paragraph: To remove open handles on enumerated directories or files Create a custom method (or function in Visual Basic) to contain your enumeration code. Apply the MethodImplAttribute attribute with the NoInlining option to the new method. For example: [MethodImplAttribute(MethodImplOptions.NoInlining)] Private void Enumerate() Include the following method calls, to run after your enumeration code: * The GC.Collect() method (no parameters). * The GC.WaitForPendingFinalizers() method. Why the attribute NoInlining? What harm would inlining do here? Why call the garbage collector manually, why not making the enumerator implement IDisposable in the first place? I suspect they use FindFirstFile()/FindNextFile() API calls for the imlementation, so FindClose() has to be called in any case if the enumeration is done.

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• Best way to access database from android

  - by Brandon Delany

  I am working on a Android app and I have a dilemma. I have a list of Objects. I have to update each of these objects with a database. I have 2 methods: Method 1: I can loop through the Objects. For each object I can connect to the server, update it, and then move on to the next Object, and so forth. Method 2: I can store the Objects in a list, send the whole list to the server, update it on the server side, then return a list of updated objects. My questions are: Which method is faster? Which method is easier on the phone's battery? By the way, Method 1 is easier for me to code :). Thank you.

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• Why does GetClusterShape return null when the cluster specification was retrieved through the GetClu

  - by Markus Olsson

  Suppose I have a virtual earth shape layer called shapeLayer1 (my creative energy is apparently at an alltime low). When i call the GetClusteredShapes method I get an array of VEClusterSpecification objects that represent each and every one of my currently visible clusters; no problem there. But when I call the GetClusterShape() method it returns null... null! Why on earth would it do that? I used firebug to confirm that the private variable of the VEClusterSpecification that's supposed to hold a reference to the shape is indeed null so it's not the method that's causing the problem. Some have suggested that this is actually documented behavior Returns null if a VEClusterSpecification object was returned from the VEShapeLayer.GetClusteredShapes Method But looking at the current MSDN documentation for the VEShape class it says: Returns if a VEClusterSpecification object was returned from the VEShapeLayer.GetClusteredShapes Method Is this a bug or a feature? Is there any known workarounds or (if it is a bug) some plan on when they are going to fix it?

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• Creating ADF Faces Comamnd Button at Runtime

  - by Frank Nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} In ADF Faces, the command button is an instance of RichCommandButton and can be created at runtime. While creating the button is not difficult at all, adding behavior to it requires knowing about how to dynamically create and add an action listener reference. The example code below shows two methods: The first method, handleButtonPress is a public method exposed on a managed bean. public void handleButtonPress(ActionEvent event){   System.out.println("Event handled");   //optional: partially refresh changed components if command   //issued as a partial submit } The second method is called in response to a user interaction or on page load and dynamically creates and adds a command button. When the button is pressed, the managed bean method – the action handler – defined above is called. The action handler is referenced using EL in the created MethodExpression instance. If the managed bean is in viewScope, backingBeanScope or pageFlowsScope, then you need to add these scopes as a prefix to the EL (as you would when configuring the managed bean reference at design time) //Create command button and add it as a child to the parent component that is passed as an //argument to this method private void reateCommandButton(UIComponent parent){   RichCommandButton edit = new RichCommandButton();   //make the request partial   edit.setPartialSubmit(true);   edit.setText("Edit");                             //compose the method expression to invoke the event handler   FacesContext fctx = FacesContext.getCurrentInstance();   Application application = fctx.getApplication();   ExpressionFactory elFactory = application.getExpressionFactory();   ELContext elContext = facesCtx.getELContext();   MethodExpression methodExpressio = null;   //Make sure the EL expression references a valid managed bean method. Ensure   //the bean scope is properly addressed    methodExpression =  elFactory.createMethodExpression(                              elContext,"#{myRequestScopeBean.handleButtonPress}",                             Object.class,new Class[] {ActionEvent.class});   //Create the command buttonaction listener reference   MethodExpressionActionListener al = null;          al= new MethodExpressionActionListener(methodExpression);    edit.addActionListener(al);     //add new command button to parent component and PPR the component for     //the button to show    parent.getChildren().add(edit);    AdfFacesContext adfFacesContext = AdfFacesContext.getCurrentInstance();     adfFacesContext.addPartialTarget(parent);  }

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• Spring/Hibernate: InvocationTargetException when deleting entity

  - by niklassaers

  I'm sorry if this question is a bit vague, but I'm quite confused. I've got a controller that calls a service to delete an entity and then create an entity in its place. In the service, I've got my DAO, and my entity, and I want to delete my entity, so I call DAO.delete(entity); Then, seemingly out of nowhere, I get an InvocationTargetException. The parameters here are: method: public org.springframework.web.servlet.ModelAndView tld.myproject.view.web.controller.MyController.replaceEntity(org.springframework.web.multipart.MultipartFile,javax.servlet.http.HttpServletRequest) target: tld.myproject.view.web.controller.MyController@185918e args: [org.springframework.web.multipart.commons.CommonsMultipartFile@14812a6, org.springframework.web.multipart.support.DefaultMultipartHttpServletRequest@c08a64] ex: java.lang.reflect.InvocationTargetException private Object doInvokeMethod(Method method, Object target, Object[] args) throws Exception { ReflectionUtils.makeAccessible(method); try { return method.invoke(target, args); } catch (InvocationTargetException ex) { ReflectionUtils.rethrowException(ex.getTargetException()); } throw new IllegalStateException("Should never get here"); } Does anyone have a suggestion to what's going on? Anything I can use in my debugging? Cheers Nik

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• Should a Unit-test replicate functionality or Test output?

  - by Daniel Beardsley

  I've run into this dilemma several times. Should my unit-tests duplicate the functionality of the method they are testing to verify it's integrity? OR Should unit tests strive to test the method with numerous manually created instances of inputs and expected outputs? I'm mainly asking the question for situations where the method you are testing is reasonably simple and it's proper operation can be verified by glancing at the code for a minute. Simplified example (in ruby): def concat_strings(str1, str2) return str1 + " AND " + str2 end Simplified functionality-replicating test for the above method: def test_concat_strings 10.times do str1 = random_string_generator str2 = random_string_generator assert_equal (str1 + " AND " + str2), concat_strings(str1, str2) end end I understand that most times the method you are testing won't be simple enough to justify doing it this way. But my question remains; is this a valid methodology in some circumstances (why or why not)?

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• Keypress detection wont work after seemingly unrelated code change

  - by LukeZaz

  I'm trying to have the Enter key cause a new 'map' to generate for my game, but for whatever reason after implementing full-screen in it the input check won't work anymore. I tried removing the new code and only pressing one key at a time, but it still won't work. Here's the check code and the method it uses, along with the newMap method: public class Game1 : Microsoft.Xna.Framework.Game { // ... protected override void Update(GameTime gameTime) { // ... // Check if Enter was pressed - if so, generate a new map if (CheckInput(Keys.Enter, 1)) { blocks = newMap(map, blocks, console); } // ... } // Method: Checks if a key is/was pressed public bool CheckInput(Keys key, int checkType) { // Get current keyboard state KeyboardState newState = Keyboard.GetState(); bool retType = false; // Return type if (checkType == 0) { // Check Type: Is key currently down? if (newState.IsKeyDown(key)) { retType = true; } else { retType = false; } } else if (checkType == 1) { // Check Type: Was the key pressed? if (newState.IsKeyDown(key)) { if (!oldState.IsKeyDown(key)) { // Key was just pressed retType = true; } else { // Key was already pressed, return false retType = false; } } } // Save keyboard state oldState = newState; // Return result if (retType == true) { return true; } else { return false; } } // Method: Generate a new map public List<Block> newMap(Map map, List<Block> blockList, Console console) { // Create new map block coordinates List<Vector2> positions = new List<Vector2>(); positions = map.generateMap(console); // Clear list and reallocate memory previously used up by it blockList.Clear(); blockList.TrimExcess(); // Add new blocks to the list using positions created by generateMap() foreach (Vector2 pos in positions) { blockList.Add(new Block() { Position = pos, Texture = dirtTex }); } // Return modified list return blockList; } // ... } and the generateMap code: // Generate a list of Vector2 positions for blocks public List<Vector2> generateMap(Console console, int method = 0) { ScreenTileWidth = gDevice.Viewport.Width / 16; ScreenTileHeight = gDevice.Viewport.Height / 16; maxHeight = gDevice.Viewport.Height; List<Vector2> blockLocations = new List<Vector2>(); if (useScreenSize == true) { Width = ScreenTileWidth; Height = ScreenTileHeight; } else { maxHeight = Height; } int startHeight = -500; // For debugging purposes, the startHeight is set to an // hopefully-unreachable value - if it returns this, something is wrong // Methods of land generation /// <summary> /// Third version land generation /// Generates a base land height as the second version does /// but also generates a 'max change' value which determines how much /// the land can raise or lower by which it now does by a random amount /// during generation /// </summary> if (method == 0) { // Get the land height startHeight = rnd.Next(1, maxHeight); int maxChange = rnd.Next(1, 5); // Amount ground will raise/lower by int curHeight = startHeight; for (int w = 0; w < Width; w++) { // Run a chance to lower/raise ground level int changeBy = rnd.Next(1, maxChange); int doChange = rnd.Next(0, 3); if (doChange == 1 && !(curHeight <= (1 + maxChange))) { curHeight = curHeight - changeBy; } else if (doChange == 2 && !(curHeight >= (29 - maxChange))) { curHeight = curHeight + changeBy; } for (int h = curHeight; h < Height; h++) { // Location variables float x = w * 16; float y = h * 16; blockLocations.Add(new Vector2(x, y)); } } console.newMsg("[INFO] Cur, height change maximum: " + maxChange.ToString()); } /// <summary> /// Second version land generator /// Generates a solid mass of land starting at a random height /// derived from either screen height or provided height value /// </summary> else if (method == 1) { // Get the land height startHeight = rnd.Next(0, 30); for (int w = 0; w < Width; w++) { for (int h = startHeight; h < ScreenTileHeight; h++) { // Location variables float x = w * 16; float y = h * 16; // Add a tile at set location blockLocations.Add(new Vector2(x, y)); } } } /// <summary> /// First version land generator /// Generates land completely randomly either across screen or /// in a box set by Width and Height values /// </summary> else { // For each tile in the map... for (int w = 0; w < Width; w++) { for (int h = 0; h < Height; h++) { // Location variables float x = w * 16; float y = h * 16; // ...decide whether or not to place a tile... if (rnd.Next(0, 2) == 1) { // ...and if so, add a tile at that location. blockLocations.Add(new Vector2(x, y)); } } } } console.newMsg("[INFO] Cur, base height: " + startHeight.ToString()); return blockLocations; } I never touched any of the above code for this when it broke - changing keys won't seem to fix it. Despite this, I have camera movement set inside another Game1 method that uses WASD and works perfectly. All I did was add a few lines of code here: private int BackBufferWidth = 1280; // Added these variables private int BackBufferHeight = 800; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = BackBufferWidth; // and this graphics.PreferredBackBufferHeight = BackBufferHeight; // this Content.RootDirectory = "Content"; this.graphics.IsFullScreen = true; // and this } When I try adding a console line to be printed in the event the key is pressed, it seems that the If is never even triggered despite the correct key being pressed.

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• .Net Reflection - Calling unexisting methods

  - by Joaozinho das Couves

  Lets say i call method M1 on class A using reflection. The method does not exist. Is there any way to put a handler on class A that says, "someone is trying to execute method M1"? Or Is it possible to add a method dinamically to a class? I want to add a method M1...Mn that always does MyStaticClass.DoAction("M1...Mn"); Something like: string methodName = "M1". A.AddMethod(methodname,x = MyStaticClass.DoAction(x)); Thanks

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• Django database caching

  - by hekevintran

  I have a Django form that uses an integer field to lookup a model object by its primary key. The form has a save() method that uses the model object referred to by the integer field. The model's manager's get() method is called twice, once in the clean method and once in the save() method: class MyForm(forms.Form): id_a = fields.IntegerField() def clean_id_a(user_id): id_a = self.cleaned_data['id_a'] try: # here is the first call to get MyModel.objects.get(id=id_a) except User.DoesNotExist: raise ValidationError('Object does not exist') def save(self): id_a = self.cleaned_data['id_a'] # here is the second call to get my_model_object = MyModel.objects.get(id=id_a) # do other stuff I wasn't sure whether this hits the database two times or one time so I returned the object itself in the clean method so that I could avoid a second get() call. Does calling get() hit the database two times? Or is the object cached in the thread? class MyForm(forms.Form): id_a = fields.IntegerField() def clean_id_a(user_id): id_a = self.cleaned_data['id_a'] try: # here is my workaround return MyModel.objects.get(id=id_a) except User.DoesNotExist: raise ValidationError('Object does not exist') def save(self): # looking up the cleaned value returns the model object my_model_object = self.cleaned_data['id_a'] # do other stuff

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• Lambda&rsquo;s for .NET made easy&hellip;

  - by mbcrump

  The purpose of my blog is to explain things for a beginner to intermediate c# programmer. I’ve seen several blog post that use lambda expressions always assuming the audience is familiar with them. The purpose of this post is to make them simple and easily understood. Let’s begin with a definition. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. So anonymous function… delegates or expression tree types? I don’t get it??? Confused yet?   Lets break this into a few definitions and jump right into the code. anonymous function – is an "inline" statement or expression that can be used wherever a delegate type is expected. delegate - is a type that references a method. Once a delegate is assigned a method, it behaves exactly like that method. The delegate method can be used like any other method, with parameters and a return value. Expression trees - represent code in a tree-like data structure, where each node is an expression, for example, a method call or a binary operation such as x < y.   Don’t worry if this still sounds confusing, lets jump right into the code with a simple 3 line program. We are going to use a Function Delegate (all you need to remember is that this delegate returns a value.) Lambda expressions are used most commonly with the Func and Action delegates, so you will see an example of both of these. Lambda Expression 3 lines. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Func<int, int> myfunc = x => x *x;             Console.WriteLine(myfunc(6).ToString());             Console.ReadLine();         }       } } Is equivalent to Old way of doing it. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {               Console.WriteLine(myFunc(6).ToString());             Console.ReadLine();         }            static int myFunc(int x)          {              return x * x;            }       } } In the example, there is a single parameter, x, and the expression is x*x. I’m going to stop here to make sure you are still with me. A lambda expression is an unnamed method written in place of a delegate instance. In other words, the compiler converts the lambda expression to either a : A delegate instance An expression tree All lambda have the following form: (parameters) => expression or statement block Now look back to the ones we have created. It should start to sink in. Don’t get stuck on the => form, use it as an identifier of a lambda. A Lamba expression can also be written in the following form: Lambda Expression. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Func<int, int> myFunc = x =>             {                 return x * x;             };               Console.WriteLine(myFunc(6).ToString());             Console.ReadLine();         }       } } This form may be easier to read but consumes more space. Lets try an Action delegate – this delegate does not return a value. Action Delegate example. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Action<string> myAction = (string x) => { Console.WriteLine(x); };             myAction("michael has made this so easy");                                   Console.ReadLine();         }       } } Lambdas can also capture outer variables (such as the example below) A lambda expression can reference the local variables and parameters of the method in which it’s defined. Outer variables referenced by a lambda expression are called captured variables. Capturing Outer Variables using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             string mike = "Michael";             Action<string> myAction = (string x) => {                 Console.WriteLine("{0}{1}", mike, x);          };             myAction(" has made this so easy");                                   Console.ReadLine();         }       } } Lamba’s can also with a strongly typed list to loop through a collection.   Used w a strongly typed list. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             List<string> list = new List<string>() { "1", "2", "3", "4" };             list.ForEach(s => Console.WriteLine(s));             Console.ReadLine();         }       } } Outputs: 1 2 3 4 I think this will get you started with Lambda’s, as always consult the MSDN documentation for more information. Still confused? Hopefully you are not.

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• context.getContextResolved appliaction stopped - begginner in java

  - by Szymad

  I have a problem with my app. I'm trying to execute query, but app stops every time. This error occurs while trying to execute query. I'm learing from Android Pro 3 book, but code presented in this book is deprecated. package com.example.contactsabuout; import android.net.Uri; import android.os.Bundle; import android.provider.Contacts; import android.provider.ContactsContract; import android.app.Activity; import android.database.Cursor; import android.util.Log; import android.content.Context; import android.view.Menu; import android.view.View; import android.widget.TextView; public class MainActivity extends Activity { private static Context context; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); MainActivity.context = getApplicationContext(); Log.v("INFO", "Completed: onCreate."); } public static Context getAppContext() { return MainActivity.context; } public void doQuery(View view) { Uri peopleBaseUri = ContactsContract.Contacts.CONTENT_URI; Log.v("II","Button clicked."); Log.v("II", "Uri for ContactsContract.Contacts: " + peopleBaseUri); Context context = getAppContext(); Log.v("II", "Got context: " + context); Cursor cur; Log.v("II", "Created cursor: cur"); cur = context.getContentResolver().query(peopleBaseUri, null, null, null, null); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.activity_main, menu); return true; } } FROM LogCat 10-28 17:45:02.513: V/INFO(4677): Completed: onCreate. 10-28 17:45:02.613: D/libEGL(4677): loaded /system/lib/egl/libGLES_android.so 10-28 17:45:02.653: D/libEGL(4677): loaded /system/lib/egl/libEGL_adreno200.so 10-28 17:45:02.723: D/libEGL(4677): loaded /system/lib/egl/libGLESv1_CM_adreno200.so 10-28 17:45:02.723: D/libEGL(4677): loaded /system/lib/egl/libGLESv2_adreno200.so 10-28 17:45:03.014: I/Adreno200-EGLSUB(4677): <ConfigWindowMatch:2078>: Format RGBA_8888. 10-28 17:45:03.054: D/OpenGLRenderer(4677): Enabling debug mode 0 10-28 17:45:03.254: D/OpenGLRenderer(4677): has fontRender patch 10-28 17:45:03.274: D/OpenGLRenderer(4677): has fontRender patch 10-28 17:45:12.873: V/II(4677): Button clicked. 10-28 17:45:12.873: V/II(4677): Uri for ContactsContract.Contacts: content://com.android.contacts/contacts, rest will be null 10-28 17:45:12.873: V/II(4677): Got context: android.app.Application@40d83d90 10-28 17:45:12.873: V/II(4677): Created cursor: cur 10-28 17:45:12.933: D/AndroidRuntime(4677): Shutting down VM 10-28 17:45:12.933: W/dalvikvm(4677): threadid=1: thread exiting with uncaught exception (group=0x40aaf228) 10-28 17:45:12.953: E/AndroidRuntime(4677): FATAL EXCEPTION: main 10-28 17:45:12.953: E/AndroidRuntime(4677): java.lang.IllegalStateException: Could not execute method of the activity 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.view.View$1.onClick(View.java:3071) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.view.View.performClick(View.java:3538) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.view.View$PerformClick.run(View.java:14330) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.os.Handler.handleCallback(Handler.java:608) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.os.Handler.dispatchMessage(Handler.java:92) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.os.Looper.loop(Looper.java:156) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.app.ActivityThread.main(ActivityThread.java:4977) 10-28 17:45:12.953: E/AndroidRuntime(4677): at java.lang.reflect.Method.invokeNative(Native Method) 10-28 17:45:12.953: E/AndroidRuntime(4677): at java.lang.reflect.Method.invoke(Method.java:511) 10-28 17:45:12.953: E/AndroidRuntime(4677): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 10-28 17:45:12.953: E/AndroidRuntime(4677): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 10-28 17:45:12.953: E/AndroidRuntime(4677): at dalvik.system.NativeStart.main(Native Method) 10-28 17:45:12.953: E/AndroidRuntime(4677): Caused by: java.lang.reflect.InvocationTargetException 10-28 17:45:12.953: E/AndroidRuntime(4677): at java.lang.reflect.Method.invokeNative(Native Method) 10-28 17:45:12.953: E/AndroidRuntime(4677): at java.lang.reflect.Method.invoke(Method.java:511) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.view.View$1.onClick(View.java:3066) 10-28 17:45:12.953: E/AndroidRuntime(4677): ... 11 more 10-28 17:45:12.953: E/AndroidRuntime(4677): Caused by: java.lang.SecurityException: Permission Denial: reading com.android.providers.contacts.HtcContactsProvider2 uri content://com.android.contacts/contacts from pid=4677, uid=10155 requires android.permission.READ_CONTACTS 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.os.Parcel.readException(Parcel.java:1332) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:182) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:136) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.content.ContentProviderProxy.query(ContentProviderNative.java:406) 10-28 17:45:12.953: E/AndroidRuntime(4677): at android.content.ContentResolver.query(ContentResolver.java:315) 10-28 17:45:12.953: E/AndroidRuntime(4677): at com.example.contactsabuout.MainActivity.doQuery(MainActivity.java:47) 10-28 17:45:12.953: E/AndroidRuntime(4677): ... 14 more I'm trying to learn android.

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• Interface and base class mix, the right way to implement this

  - by Lerxst

  I have some user controls which I want to specify properties and methods for. They inherit from a base class, because they all have properties such as "Foo" and "Bar", and the reason I used a base class is so that I dont have to manually implement all of these properties in each derived class. However, I want to have a method that is only in the derived classes, not in the base class, as the base class doesn't know how to "do" the method, so I am thinking of using an interface for this. If i put it in the base class, I have to define some body to return a value (which would be invalid), and always make sure that the overriding method is not calling the base. method Is the right way to go about this to use both the base class and an interface to expose the method? It seems very round-about, but every way i think about doing it seems wrong... Let me know if the question is not clear, it's probably a dumb question but I want to do this right.

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• Authorization in a more purely OOP style...

  - by noblethrasher

  I've never seen this done but I had an idea of doing authorization in a more purely OO way. For each method that requires authorization we associate a delegate. During initialization of the class we wire up the delegates so that they point to the appropriate method (based on the user's rights). For example: class User { private deleteMemberDelegate deleteMember; public StatusMessage DeleteMember(Member member) { if(deleteMember != null) { deleteMember(member); } } //other methods defined similarly... User(string name, string password) //cstor. { //wire up delegates based on user's rights. //Thus we handle authentication and authorization in the same method. } } This way the client code never has to explictly check whether or not a user is in a role, it just calls the method. Of course each method should return a status message so that we know if and why it failed. Thoughts?

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• Inheritance classes in Scheme

  - by DreamWalker

  Now I research OOP-part of Scheme. I can define class in Scheme like this: (define (create-queue) (let ((mpty #t) (the-list '())) (define (enque value) (set! the-list (append the-list (list value))) (set! mpty #f) the-list) (define (deque) (set! the-list (cdr the-list)) (if (= (length the-list) 0) (set! mpty #t)) the-list) (define (isEmpty) mpty) (define (ptl) the-list) (define (dispatch method) (cond ((eq? method 'enque) enque) ((eq? method 'deque) deque) ((eq? method 'isEmpty) isEmpty) ((eq? method 'print) ptl))) dispatch)) (Example from css.freetonik.com) Can I implement class inheritance in Scheme?

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• Create a New .Net Profiler Api

  - by daniel

  Hi everybody! i m a new programmer in .Net Profiler and Visual C++, i read many forums and weblogs for .Net Profiling and i have this question. my Profiler application must be a unmanaged code or i can use some class in .Net in my application? and what type of project i must create ATL with MFC Or ..? another question is how can i register my profiler dll file that every application of my computer use this profiler? where the best situation for re-write IL of a method (Enter method of profiler or JITCompilationStarted)? how can i get input variables of old method and send to new method? how can i change IL of a property or whole of a class? i want chane all datetime format of my dlls, and i think that i must search name of those method in JITCompilationStarted and then rewrite that methods,Do u have any better solution? thanks alot.

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• php java in memory database

  - by msaif

  i need to load data as array to memory in PHP.but in PHP if i write $array= array("1","2"); in test.php then this $array variable is initialized every time user requests.if we request test.php 100 times by clicking 100 times browser refresh button then this $array variable will be executed 100 times. but i need to execute the $array variable only one time for first time request and subsequent request of test.php must not execute the $array variable.but only use that memory location.how can i do that in PHP. but in JAVA SEVRVLET it is easy to execute,just write the $array variable in one time execution of init() method of servlet lifecycle method and subsequent request of that servlet dont execute init() method but service() method but service() method always uses that $array memeory location. all i want to initilize $array variable once but use that memory loc from subsequent request in PHP.is there any possiblity in PHP?

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• problems with extended classes and overwrite with methods

  - by Marco

  I have a .net website written in C# and will make functionalities that other developers can use. So i will make some default implementation and a developer can overwrite some methods Example: i have a class ShoppingCart and a class Product the class product haves a method getProductPrice the shoppingcart will call the method getProductPrice for calculating the total price of cart The Shoppingcart and Product are in the same project and i will give the developers the .dll so they can't change the source code so we can update the assembly later So they need to make a other project and extend the product class and overwrite the method getProductPrice so they can implement there own logic The problem is that the shoppingcart will not call the extended method but the original If we make already a extended project for the developers and the shoppingcart will call the extended method then we have a circular reference because the extended product needs a reference to product and the shopping cart to the extended product partial classes also don't works because we only can use partials within the same assembly anyone a suggestion ? thanks in advance

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• JavaScript: How to create a new instance of a class without using the new keyword?

  - by Alessandro Vernet

  I think the following code will make the question clear. // My class var Class = function() { console.log("Constructor"); }; Class.prototype = { method: function() { console.log("Method");} } // Creating an instance with new var object1 = new Class(); object1.method(); console.log("New returned", object1); // How to write a factory which can't use the new keyword? function factory(clazz) { // Assume this function can't see "Class", but only sees its parameter "clazz". return clazz.call(); // Calls the constructor, but no new object is created return clazz.new(); // Doesn't work because there is new() method }; var object2 = factory(Class); object2.method(); console.log("Factory returned", object2);

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• java methods and race condition in a jsp/servlets application.

  - by A.S al-shammari

  Hi. Suppose that I have a method called doSomething() and I want to use this method in a multithreaded application (each servlet inherits from HttpServlet).I'm wondering if it is possible that a race condition will occur in the following cases: doSomething() is not staic method and it writes values to a database. doSomething() is static method but it does not write values to a database. what I have noticed that many methods in my application may lead to a race condition or dirty read/write. for example , I have a Poll System , and for each voting operation, a certain method will change a single cell value for that poll as the following: [poll_id | poll_data ] [1 | {choice_1 : 10, choice_2 : 20}] will the JSP/Servlets app solve these issues by itself, or I have to solve all that by myself? Thanks..

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• Sending an email when an Exception is Thrown

  - by hariubc

  Hi: I have written a java class where if a method throws an exception, an email is sent, via java mail, with a report to the administrators. It works - my question is w.r.t elegance - to catch the exception thrown by the main method, the sendEmail() method resides in the catch block of the main method. The sendEmail() method has its own try-catch block. In effect - it looks like below - is there a more beautiful way of writing this? try { foo; } catch { try{ sendEmail(); } catch { log(e.message); } }

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• javascript inherance? with Private vars and methods too

  - by Totty

  Hy i need to inherent a class from another. Parent has private var "_data" and private method "_test" and public method "add" Now the child have a public method "add", that uses the private method from the parent "_test" and the private var "_data". How do i do this? var Parent = function(){ var _data = {}; var _test = function(){alert('test')}; this.add = function(){alert('add from parent')} } var Child = function(){ this.add = function(){// here uses the _data and _test from the Parent class alert('add from child') } } // something to inherent Child from Parent // instance Child and use the add method And i think im miss the prototype concept (http://stackoverflow.com/questions/892467/javascript-inheritance)

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• Java reflection for generics

  - by Vijay Bhore

  I am using Java Reflection to expose methods in custom eclipse tool. I am writing method getReturnType which accepts java.lang.reflect.Method as input and returns object of Class private static Class<?> getReturnType(Method method) { Type type = ((ParameterizedType)method.getGenericReturnType()).getRawType(); return getClass(type); } This code compiles well but at runtime i get the below exception while casting Type to ParameterizedType. java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType Please suggest. Thanks!

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• Are closures in javascript recompiled

  - by Discodancer

  Let's say we have this code (forget about prototypes for a moment): function A(){ var foo = 1; this.method = function(){ return foo; } } var a = new A(); is the inner function recompiled each time the function A is run? Or is it better (and why) to do it like this: function method = function(){ return this.foo; } function A(){ this.foo = 1; this.method = method; } var a = new A(); Or are the javascript engines smart enough not to create a new 'method' function every time? Specifically Google's v8 and node.js. Also, any general recommendations on when to use which technique are welcome. In my specific example, it really suits me to use the first example, but I know thath the outer function will be instantiated many times.

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• Java generics question

  - by user247866

  So I have 3 classes. Abstract class A Class B extends class A independent Class C In class D that contains the main method, I create a list of instances of class B List<B> b = methodCall(); // the method returns a list of instances of class B Now in class C I have one method that is common to both A and B, and hence I don't want to duplicate it. I want to have one method that takes as input an instance of class A, as follows: public void someMethod(List<A> a) However, when I do: C c = new C(); c.someMethod(b); I get an error that some-method is not applicable for the argument List<B>, instead it's expecting to get List<A>. Is there a good way to fix this problem? Many thanks!

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• Why is run() not immediately called when start() called on a thread object in java

  - by pi

  Or is it? I have a thread object from: Thread myThread = new Thread(pObject); Where pObject is an object of a class implementing the Runnable interface and then I have the start method called on the thread object like so: myThread.start(); Now, my understanding is that when start() is called, the JVM implicitly (and immediately) calls the run() method which may be overridden (as it is in my case) However, in my case, it appears that the start() method is not called immediately (as desired) but until the other statements/methods are completed from the calling block i.e. if I had a method after the start() call like so: myThread.start(); doSomethingElse(); doSomthingElse() gets executed before the run() method is run at all. Perhaps I am wrong with the initial premise that run() is always called right after the start() is called. Please help! The desired again is making executing run() right after start(). Thanks.

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