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  • How to overcome case sensitive problem with contains method.??

    - by Srikanth
    Is there any solution to overcome case-sensitive problem for contains method. I have code like below string str = m_name; return avobj.Viewname.Contains(str); Eg: Welcome Here welcome here Both are same names but case is different. If I give 'W' in search box it is returning only 1st one. but I need both names display. I am storing the names in collection. And resultant values ( searched values ) are storing in List.

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  • How to get just free heap size (not together w stack/method mem) in Java?

    - by Pentium10
    I want to calculate the heap usage for my app. I would like to get a procent value of Heap size only. How do I get the value in code for the current running app? EDIT The upvoted answer is NOT complete/correct. The values returned by those methods include stack and method area too, and I need to monitor only heap size. With that code I got HeapError exception when I reached 43%, so I can't use those methods to monitor just heap.

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  • Is it possible to pass arithmatic operators to a method in java?

    - by user349611
    Right now I'm going to have to write a method that looks like this: public String Calculate(String Operator, Double Operand1, Double Operand2) { if (Operator.equals("+")) { return String.valueOf(Operand1 + Operand2); } else if (Operator.equals("-")) { return String.valueOf(Operand1 - Operand2); } else if (Operator.equals("*")) { return String.valueOf(Operand1 * Operand2); } else { return "error..."; } } It would be nice if I could write the code more like this: public String Calculate(String Operator, Double Operand1, Double Operand2) { return String.valueOf(Operand1 Operator Operand2); } So Operator would replace the Arithmetic Operators (+, -, *, /...) Does anyone know if something like this is possible in java?

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  • Is there a method I can override on a JavaScript object to control what is displayed by console.log?

    - by agnoster
    I'm thinking in particular of Chrome, though Firebug would be interesting to. I've tried toString() and valueOf(), but neither of those seem to be used. Interestingly, if I take a function it'll display the function definition - but then if I add a toString() method it will show null! var a = function(){}; console.log(a); // output: function (){} a.toString = function(){ return 'a'; }; console.log(a); // output: null a.valueOf = function(){ return 'v'; }; console.log(a); // output: null Any ideas?

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  • Is it possible in Scala to force the caller to specify a type parameter for a polymorphic method ?

    - by Alex Kravets
    //API class Node class Person extends Node object Finder { def find[T <: Node](name: String): T = doFind(name).asInstanceOf[T] } //Call site (correct) val person = find[Person]("joe") //Call site (dies with a ClassCast inside b/c inferred type is Nothing) val person = find("joe") In the code above the client site "forgot" to specify the type parameter, as the API writer I want that to mean "just return Node". Is there any way to define a generic method (not a class) to achieve this (or equivalent). Note: using a manifest inside the implementation to do the cast if (manifest != scala.reflect.Manifest.Nothing) won't compile ... I have a nagging feeling that some Scala Wizard knows how to use Predef.<:< for this :-) Ideas ?

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  • Is a VPN a good method for protecting data in an untrusted network? [closed]

    - by john
    I will be connecting my laptop in an untrusted network. If I setup OpenVpn on a server and use a vpn client on the laptop to connect through it, is it enough? Can someone perform a MITM attack or otherwise eavesdrop on my traffic? If someone on the local network port-scans my laptop, will the open ports be accessible to him while I use the VPN tunnel? Is there anything else I should keep in mind?

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  • How does ruby allow a method and a Class with the same name?

    - by Daniel Beardsley
    I happened to be working on a Singleton class in ruby and just remembered the way it works in factory_girl. They worked it out so you can use both the long way Factory.create(...) and the short way Factory(...) I thought about it and was curious to see how they made the class Factory also behave like a method. They simply used Factory twice like so: def Factory (args) ... end class Factory ... end My Question is: How does ruby accomplish this? and Is there danger in using this seemingly quirky pattern?

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  • Java inheritance 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 = method-call();` // 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 some-method(LIst<A> a) However, when I do: C c = new C(). c. some-method(b) I get an error that some-method is not applicable for the argument List, instead it's expecting to get List. Is there a good way to fix this problem? Many thanks!

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  • Where does the 'method' implementation go? (I'm a newbie)

    - by Spokane-Dude
    I have this code: #import "SQLiteDB.h" @implementation SQLiteDB @synthesize db, dbPath, databaseKey; @end //-------------- check for database or create it ----------------| - (void)checkForDatabase { NSFileManager *filemanager = [NSFileManager defaultManager]; NSString *databasePath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingString:@"/ppcipher.s3db"]; if(![filemanager fileExistsAtPath:databasePath]) { //Database doesn't exist yet, so we create it... NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingString:@"/ppcipher.s3db"]; sqlite3 *db; if(sqlite3_open(databasePath, db) == SQLITE_OK) { } } } It's complaining that "method definition not in @implementation context". So where does it go? (I tried in the .h file, but still get the error)

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  • What is the difference between "render a view" and send the response using the Response's method "sendResponse()"?

    - by Green
    I've asked a question about what is "rendering a view". Got some answers: Rendering a view means showing up a View eg html part to user or browser. and So by rendering a view, the MVC framework has handled the data in the controller and done the backend work in the model, and then sends that data to the View to be output to the user. and render just means to emit. To print. To echo. To write to some source (probably stdout). but don't understand then the difference between rendering a view and using the Response class to send the output to the user using its sendResponse() method. If render a view means to echo the output to the user then why sendResponse() exists and vise versa? sendResponse() exactly sends headers and after headers outputs the body. They solve the same tasks but differently? What is the difference?

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  • Loose Coupling in Object Oriented Design

    - by m3th0dman
    I am trying to learn GRASP and I found this explained (here on page 3) about Low Coupling and I was very surprised when I found this: Consider the method addTrack for an Album class, two possible methods are: addTrack( Track t ) and addTrack( int no, String title, double duration ) Which method reduces coupling? The second one does, since the class using the Album class does not have to know a Track class. In general, parameters to methods should use base types (int, char ...) and classes from the java.* packages. I tend to diasgree with this; I believe addTrack(Track t) is better than addTrack(int no, String title, double duration) due to various reasons: It is always better for a method to as fewer parameters as possible (according to Uncle Bob's Clean Code none or one preferably, 2 in some cases and 3 in special cases; more than 3 needs refactoring - these are of course recommendations not holly rules). If addTrack is a method of an interface, and the requirements need that a Track should have more information (say year or genre) then the interface needs to be changed and so that the method should supports another parameter. Encapsulation is broke; if addTrack is in an interface, then it should not know the internals of the Track. It is actually more coupled in the second way, with many parameters. Suppose the no parameter needs to be changed from int to long because there are more than MAX_INT tracks (or for whatever reason); then both the Track and the method need to be changed while if the method would be addTrack(Track track) only the Track would be changed. All the 4 arguments are actually connected with each other, and some of them are consequences from others. Which approach is better?

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  • Error in code of basic game using multiple sprites and surfaceView [on hold]

    - by Khagendra Nath Mahato
    I am a beginner to android and i was trying to make a basic game with the help of an online video tutorial. I am having problem with the multi-sprites and how to use with surfaceview.The application fails launching. Here is the code of the game.please help me. package com.example.killthemall; import java.util.ArrayList; import java.util.List; import java.util.Random; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Rect; import android.os.Bundle; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.widget.Toast; public class Game extends Activity { KhogenView View1; @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); while(true){ try { OurThread.join(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); }} } Thread OurThread; int herorows = 4; int herocolumns = 3; int xpos, ypos; int xspeed; int yspeed; int herowidth; int widthnumber = 0; int heroheight; Rect src; Rect dst; int round; Bitmap bmp1; // private Bitmap bmp1;//change name public List<Sprite> sprites = new ArrayList<Sprite>() { }; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); View1 = new KhogenView(this); setContentView(View1); sprites.add(createSprite(R.drawable.image)); sprites.add(createSprite(R.drawable.bad1)); sprites.add(createSprite(R.drawable.bad2)); sprites.add(createSprite(R.drawable.bad3)); sprites.add(createSprite(R.drawable.bad4)); sprites.add(createSprite(R.drawable.bad5)); sprites.add(createSprite(R.drawable.bad6)); sprites.add(createSprite(R.drawable.good1)); sprites.add(createSprite(R.drawable.good2)); sprites.add(createSprite(R.drawable.good3)); sprites.add(createSprite(R.drawable.good4)); sprites.add(createSprite(R.drawable.good5)); sprites.add(createSprite(R.drawable.good6)); } private Sprite createSprite(int image) { // TODO Auto-generated method stub bmp1 = BitmapFactory.decodeResource(getResources(), image); return new Sprite(this, bmp1); } public class KhogenView extends SurfaceView implements Runnable { SurfaceHolder OurHolder; Canvas canvas = null; Random rnd = new Random(); { xpos = rnd.nextInt(canvas.getWidth() - herowidth)+herowidth; ypos = rnd.nextInt(canvas.getHeight() - heroheight)+heroheight; xspeed = rnd.nextInt(10 - 5) + 5; yspeed = rnd.nextInt(10 - 5) + 5; } public KhogenView(Context context) { super(context); // TODO Auto-generated constructor stub OurHolder = getHolder(); OurThread = new Thread(this); OurThread.start(); } @Override public void run() { // TODO Auto-generated method stub herowidth = bmp1.getWidth() / 3; heroheight = bmp1.getHeight() / 4; boolean isRunning = true; while (isRunning) { if (!OurHolder.getSurface().isValid()) continue; canvas = OurHolder.lockCanvas(); canvas.drawRGB(02, 02, 50); for (Sprite sprite : sprites) { if (widthnumber == 3) widthnumber = 0; update(); getdirection(); src = new Rect(widthnumber * herowidth, round * heroheight, (widthnumber + 1) * herowidth, (round + 1)* heroheight); dst = new Rect(xpos, ypos, xpos + herowidth, ypos+ heroheight); canvas.drawBitmap(bmp1, src, dst, null); } widthnumber++; OurHolder.unlockCanvasAndPost(canvas); } } public void update() { try { Thread.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } if (xpos + xspeed <= 0) xspeed = 40; if (xpos >= canvas.getWidth() - herowidth) xspeed = -50; if (ypos + yspeed <= 0) yspeed = 45; if (ypos >= canvas.getHeight() - heroheight) yspeed = -55; xpos = xpos + xspeed; ypos = ypos + yspeed; } public void getdirection() { double angleinteger = (Math.atan2(yspeed, xspeed)) / (Math.PI / 2); round = (int) (Math.round(angleinteger) + 2) % herorows; // Toast.makeText(this, String.valueOf(round), // Toast.LENGTH_LONG).show(); } } public class Sprite { Game game; private Bitmap bmp; public Sprite(Game game, Bitmap bmp) { // TODO Auto-generated constructor stub this.game = game; this.bmp = bmp; } } } Here is the LogCat if it helps.... 08-22 23:18:06.980: D/AndroidRuntime(28151): Shutting down VM 08-22 23:18:06.980: W/dalvikvm(28151): threadid=1: thread exiting with uncaught exception (group=0xb3f6f4f0) 08-22 23:18:06.980: D/AndroidRuntime(28151): procName from cmdline: com.example.killthemall 08-22 23:18:06.980: E/AndroidRuntime(28151): in writeCrashedAppName, pkgName :com.example.killthemall 08-22 23:18:06.980: D/AndroidRuntime(28151): file written successfully with content: com.example.killthemall StringBuffer : ;com.example.killthemall 08-22 23:18:06.990: I/Process(28151): Sending signal. PID: 28151 SIG: 9 08-22 23:18:06.990: E/AndroidRuntime(28151): FATAL EXCEPTION: main 08-22 23:18:06.990: E/AndroidRuntime(28151): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.killthemall/com.example.killthemall.Game}: java.lang.NullPointerException 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.os.Handler.dispatchMessage(Handler.java:99) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.os.Looper.loop(Looper.java:130) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.ActivityThread.main(ActivityThread.java:3683) 08-22 23:18:06.990: E/AndroidRuntime(28151): at java.lang.reflect.Method.invokeNative(Native Method) 08-22 23:18:06.990: E/AndroidRuntime(28151): at java.lang.reflect.Method.invoke(Method.java:507) 08-22 23:18:06.990: E/AndroidRuntime(28151): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:880) 08-22 23:18:06.990: E/AndroidRuntime(28151): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:638) 08-22 23:18:06.990: E/AndroidRuntime(28151): at dalvik.system.NativeStart.main(Native Method) 08-22 23:18:06.990: E/AndroidRuntime(28151): Caused by: java.lang.NullPointerException 08-22 23:18:06.990: E/AndroidRuntime(28151): at com.example.killthemall.Game$KhogenView.<init>(Game.java:96) 08-22 23:18:06.990: E/AndroidRuntime(28151): at com.example.killthemall.Game.onCreate(Game.java:58) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 08-22 23:18:06.990: E/AndroidRuntime(28151): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 08-22 23:18:06.990: E/AndroidRuntime(28151): ... 11 more 08-22 23:18:18.050: D/AndroidRuntime(28191): Shutting down VM 08-22 23:18:18.050: W/dalvikvm(28191): threadid=1: thread exiting with uncaught exception (group=0xb3f6f4f0) 08-22 23:18:18.050: I/Process(28191): Sending signal. PID: 28191 SIG: 9 08-22 23:18:18.050: D/AndroidRuntime(28191): procName from cmdline: com.example.killthemall 08-22 23:18:18.050: E/AndroidRuntime(28191): in writeCrashedAppName, pkgName :com.example.killthemall 08-22 23:18:18.050: D/AndroidRuntime(28191): file written successfully with content: com.example.killthemall StringBuffer : ;com.example.killthemall 08-22 23:18:18.050: E/AndroidRuntime(28191): FATAL EXCEPTION: main 08-22 23:18:18.050: E/AndroidRuntime(28191): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.killthemall/com.example.killthemall.Game}: java.lang.NullPointerException 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.os.Handler.dispatchMessage(Handler.java:99) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.os.Looper.loop(Looper.java:130) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.ActivityThread.main(ActivityThread.java:3683) 08-22 23:18:18.050: E/AndroidRuntime(28191): at java.lang.reflect.Method.invokeNative(Native Method) 08-22 23:18:18.050: E/AndroidRuntime(28191): at java.lang.reflect.Method.invoke(Method.java:507) 08-22 23:18:18.050: E/AndroidRuntime(28191): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:880) 08-22 23:18:18.050: E/AndroidRuntime(28191): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:638) 08-22 23:18:18.050: E/AndroidRuntime(28191): at dalvik.system.NativeStart.main(Native Method) 08-22 23:18:18.050: E/AndroidRuntime(28191): Caused by: java.lang.NullPointerException 08-22 23:18:18.050: E/AndroidRuntime(28191): at com.example.killthemall.Game$KhogenView.<init>(Game.java:96) 08-22 23:18:18.050: E/AndroidRuntime(28191): at com.example.killthemall.Game.onCreate(Game.java:58) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 08-22 23:18:18.050: E/AndroidRuntime(28191): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 08-22 23:18:18.050: E/AndroidRuntime(28191): ... 11 more

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  • SQL SERVER – Three Methods to Insert Multiple Rows into Single Table – SQL in Sixty Seconds #024 – Video

    - by pinaldave
    One of the biggest ask I have always received from developers is that if there is any way to insert multiple rows into a single table in a single statement. Currently when developers have to insert any value into the table they have to write multiple insert statements. First of all this is not only boring it is also very much time consuming as well. Additionally, one has to repeat the same syntax so many times that the word boring becomes an understatement. In the following quick video we have demonstrated three different methods to insert multiple values into a single table. -- Insert Multiple Values into SQL Server CREATE TABLE #SQLAuthority (ID INT, Value VARCHAR(100)); Method 1: Traditional Method of INSERT…VALUE -- Method 1 - Traditional Insert INSERT INTO #SQLAuthority (ID, Value) VALUES (1, 'First'); INSERT INTO #SQLAuthority (ID, Value) VALUES (2, 'Second'); INSERT INTO #SQLAuthority (ID, Value) VALUES (3, 'Third'); Clean up -- Clean up TRUNCATE TABLE #SQLAuthority; Method 2: INSERT…SELECT -- Method 2 - Select Union Insert INSERT INTO #SQLAuthority (ID, Value) SELECT 1, 'First' UNION ALL SELECT 2, 'Second' UNION ALL SELECT 3, 'Third'; Clean up -- Clean up TRUNCATE TABLE #SQLAuthority; Method 3: SQL Server 2008+ Row Construction -- Method 3 - SQL Server 2008+ Row Construction INSERT INTO #SQLAuthority (ID, Value) VALUES (1, 'First'), (2, 'Second'), (3, 'Third'); Clean up -- Clean up DROP TABLE #SQLAuthority; Related Tips in SQL in Sixty Seconds: SQL SERVER – Insert Multiple Records Using One Insert Statement – Use of UNION ALL SQL SERVER – 2008 – Insert Multiple Records Using One Insert Statement – Use of Row Constructor I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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  • A Simple Approach For Presenting With Code Samples

    - by Jesse Taber
    Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/07/31/a-simple-approach-for-presenting-with-code-samples.aspxI’ve been getting ready for a presentation and have been struggling a bit with the best way to show and execute code samples. I don’t present often (hardly ever), but when I do I like the presentation to have a lot of succinct and executable code snippets to help illustrate the points that I’m making. Depending on what the presentation is about, I might just want to build an entire sample application that I would run during the presentation. In other cases, however, building a full-blown application might not really be the best way to present the code. The presentation I’m working on now is for an open source utility library for dealing with dates and times. I could have probably cooked up a sample app for accepting date and time input and then contrived ways in which it could put the library through its paces, but I had trouble coming up with one app that would illustrate all of the various features of the library that I wanted to highlight. I finally decided that what I really needed was an approach that met the following criteria: Simple: I didn’t want the user interface or overall architecture of a sample application to serve as a distraction from the demonstration of the syntax of the library that the presentation is about. I want to be able to present small bits of code that are focused on accomplishing a single task. Several of these examples will look similar, and that’s OK. I want each sample to “stand on its own” and not rely much on external classes or methods (other than the library that is being presented, of course). “Debuggable” (not really a word, I know): I want to be able to easily run the sample with the debugger attached in Visual Studio should I want to step through any bits of code and show what certain values might be at run time. As far as I know this rules out something like LinqPad, though using LinqPad to present code samples like this is actually a very interesting idea that I might explore another time. Flexible and Selectable: I’m going to have lots of code samples to show, and I want to be able to just package them all up into a single project or module and have an easy way to just run the sample that I want on-demand. Since I’m presenting on a .NET framework library, one of the simplest ways in which I could execute some code samples would be to just create a Console application and use Console.WriteLine to output the pertinent info at run time. This gives me a “no frills” harness from which to run my code samples, and I just hit ‘F5’ to run it with the debugger. This satisfies numbers 1 and 2 from my list of criteria above, but item 3 is a little harder. By default, just running a console application is going to execute the ‘main’ method, and then terminate the program after all code is executed. If I want to have several different code samples and run them one at a time, it would be cumbersome to keep swapping the code I want in and out of the ‘main’ method of the console application. What I really want is an easy way to keep the console app running throughout the whole presentation and just have it run the samples I want when I want. I could setup a simple Windows Forms or WPF desktop application with buttons for the different samples, but then I’m getting away from my first criteria of keeping things as simple as possible. Infinite Loops To The Rescue I found a way to have a simple console application satisfy all three of my requirements above, and it involves using an infinite loop and some Console.ReadLine calls that will give the user an opportunity to break out and exit the program. (All programs that need to run until they are closed explicitly (or crash!) likely use similar constructs behind the scenes. Create a new Windows Forms project, look in the ‘Program.cs’ that gets generated, and then check out the docs for the Application.Run method that it calls.). Here’s how the main method might look: 1: static void Main(string[] args) 2: { 3: do 4: { 5: Console.Write("Enter command or 'exit' to quit: > "); 6: var command = Console.ReadLine(); 7: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 8: { 9: Console.WriteLine("Quitting."); 10: break; 11: } 12: 13: } while (true); 14: } The idea here is the app prompts me for the command I want to run, or I can type in ‘exit’ to break out of the loop and let the application close. The only trick now is to create a set of commands that map to each of the code samples that I’m going to want to run. Each sample is already encapsulated in a single public method in a separate class, so I could just write a big switch statement or create a hashtable/dictionary that maps command text to an Action that will invoke the proper method, but why re-invent the wheel? CLAP For Your Own Presentation I’ve blogged about the CLAP library before, and it turns out that it’s a great fit for satisfying criteria #3 from my list above. CLAP lets you decorate methods in a class with an attribute and then easily invoke those methods from within a console application. CLAP was designed to take the arguments passed into the console app from the command line and parse them to determine which method to run and what arguments to pass to that method, but there’s no reason you can’t re-purpose it to accept command input from within the infinite loop defined above and invoke the corresponding method. Here’s how you might define a couple of different methods to contain two different code samples that you want to run during your presentation: 1: public static class CodeSamples 2: { 3: [Verb(Aliases="one")] 4: public static void SampleOne() 5: { 6: Console.WriteLine("This is sample 1"); 7: } 8:   9: [Verb(Aliases="two")] 10: public static void SampleTwo() 11: { 12: Console.WriteLine("This is sample 2"); 13: } 14: } A couple of things to note about the sample above: I’m using static methods. You don’t actually need to use static methods with CLAP, but the syntax ends up being a bit simpler and static methods happen to lend themselves well to the “one self-contained method per code sample” approach that I want to use. The methods are decorated with a ‘Verb’ attribute. This tells CLAP that they are eligible targets for commands. The “Aliases” argument lets me give them short and easy-to-remember aliases that can be used to invoke them. By default, CLAP just uses the full method name as the command name, but with aliases you can simply the usage a bit. I’m not using any parameters. CLAP’s main feature is its ability to parse out arguments from a command line invocation of a console application and automatically pass them in as parameters to the target methods. My code samples don’t need parameters ,and honestly having them would complicate giving the presentation, so this is a good thing. You could use this same approach to invoke methods with parameters, but you’d have a couple of things to figure out. When you invoke a .NET application from the command line, Windows will parse the arguments and pass them in as a string array (called ‘args’ in the boilerplate console project Program.cs). The parsing that gets done here is smart enough to deal with things like treating strings in double quotes as one argument, and you’d have to re-create that within your infinite loop if you wanted to use parameters. I plan on either submitting a pull request to CLAP to add this capability or maybe just making a small utility class/extension method to do it and posting that here in the future. So I now have a simple class with static methods to contain my code samples, and an infinite loop in my ‘main’ method that can accept text commands. Wiring this all up together is pretty easy: 1: static void Main(string[] args) 2: { 3: do 4: { 5: try 6: { 7: Console.Write("Enter command or 'exit' to quit: > "); 8: var command = Console.ReadLine(); 9: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 10: { 11: Console.WriteLine("Quitting."); 12: break; 13: } 14:   15: Parser.Run<CodeSamples>(new[] { command }); 16: Console.WriteLine("---------------------------------------------------------"); 17: } 18: catch (Exception ex) 19: { 20: Console.Error.WriteLine("Error: " + ex.Message); 21: } 22:   23: } while (true); 24: } Note that I’m now passing the ‘CodeSamples’ class into the CLAP ‘Parser.Run’ as a type argument. This tells CLAP to inspect that class for methods that might be able to handle the commands passed in. I’m also throwing in a little “----“ style line separator and some basic error handling (because I happen to know that some of the samples are going to throw exceptions for demonstration purposes) and I’m good to go. Now during my presentation I can just have the console application running the whole time with the debugger attached and just type in the alias of the code sample method that I want to run when I want to run it.

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  • Style bits vs. Separate bool's

    - by peterchen
    My main platform (WinAPI) still heavily uses bits for control styles etc. (example). When introducing custom controls, I'm permanently wondering whether to follow that style or rather use individual bool's. Let's pit them against each other: enum EMyCtrlStyles { mcsUseFileIcon = 1, mcsTruncateFileName = 2, mcsUseShellContextMenu = 4, }; void SetStyle(DWORD mcsStyle); void ModifyStyle(DWORD mcsRemove, DWORD mcsAdd); DWORD GetStyle() const; ... ctrl.SetStyle(mcsUseFileIcon | mcsUseShellContextMenu); vs. CMyCtrl & SetUseFileIcon(bool enable = true); bool GetUseFileIcon() const; CMyCtrl & SetTruncteFileName(bool enable = true); bool GetTruncteFileName() const; CMyCtrl & SetUseShellContextMenu(bool enable = true); bool GetUseShellContextMenu() const; ctrl.SetUseFileIcon().SetUseShellContextMenu(); As I see it, Pro Style Bits Consistent with platform less library code (without gaining complexity), less places to modify for adding a new style less caller code (without losing notable readability) easier to use in some scenarios (e.g. remembering / transferring settings) Binary API remains stable if new style bits are introduced Now, the first and the last are minor in most cases. Pro Individual booleans Intellisense and refactoring tools reduce the "less typing" effort Single Purpose Entities more literate code (as in "flows more like a sentence") No change of paradim for non-bool properties These sound more modern, but also "soft" advantages. I must admit the "platform consistency" is much more enticing than I could justify, the less code without losing much quality is a nice bonus. 1. What do you prefer? Subjectively, for writing the library, or for writing client code? 2. Any (semi-) objective statements, studies, etc.?

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  • converting a mouse click to a ray

    - by Will
    I have a perspective projection. When the user clicks on the screen, I want to compute the ray between the near and far planes that projects from the mouse point, so I can do some ray intersection code with my world. I am using my own matrix and vector and ray classes and they all work as expected. However, when I try and convert the ray to world coordinates my far always ends up as 0,0,0 and so my ray goes from the mouse click to the centre of the object space, rather than through it. (The x and y coordinates of near and far are identical, they differ only in the z coordinates where they are negatives of each other) GLint vp[4]; glGetIntegerv(GL_VIEWPORT,vp); matrix_t mv, p; glGetFloatv(GL_MODELVIEW_MATRIX,mv.f); glGetFloatv(GL_PROJECTION_MATRIX,p.f); const matrix_t inv = (mv*p).inverse(); const float unit_x = (2.0f*((float)(x-vp[0])/(vp[2]-vp[0])))-1.0f, unit_y = 1.0f-(2.0f*((float)(y-vp[1])/(vp[3]-vp[1]))); const vec_t near(vec_t(unit_x,unit_y,-1)*inv); const vec_t far(vec_t(unit_x,unit_y,1)*inv); ray = ray_t(near,far-near); What have I got wrong? (How do you unproject the mouse-point?)

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  • What are the best practices for phasing out obsolete code?

    - by P.Brian.Mackey
    I have the need to phase out an obsolete method. I am aware of the [Obsolete] attribute. Does Microsoft have a recommended best practice guide for doing this? Here's my current plan: A. I do not want to create a new assembly because developers would have to add a new reference to their projects and I expect to get a lot of grief from my boss and co-workers if they must do this. We also do not maintain multiple assembly versions. We only use the latest version. Changing this practice would require changing our deployment process which is a big issue (have to teach people how to do things with TFS instead of FinalBuilder and get them to give up FinalBuilder) B. Mark the old method obsolete. C. Because the implementation is changing (not the method signature), I need to rename the method rather than create an overload. So, to make users aware of the proper method I plan to add a message to the [Obsolete] attribute. This part bothers me, because the only change I'm making is decoupling the method from the connection string. But, because I'm not adding a new assembly, I see no way around this. Result: [Obsolete("Please don't use this anymore because it does not implement IMyDbProvider. Use XXX instead.")]; /// <summary> /// /// </summary> /// <param name="settingName"></param> /// <returns></returns> public static Dictionary<string, Setting> ReadSettings(string settingName) { return ReadSettings(settingName, SomeGeneralClass.ConnectionString); } public Dictionary<string, Setting> ReadSettings2(string settingName) { return ReadSettings(settingName);// IMyDbProvider.ConnectionString private member added to class. Probably have to make this an instance method. }

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  • Using Exception Handler in an ADF Task Flow

    - by anmprs
    Problem Statement: Exception thrown in a task flow gets wrapped in an exception that gives an unintelligible error message to the user. Figure 1 Solution 1. Over-writing the error message with a user-friendly error message. Figure 2 Steps to code 1. Generating an exception: Write a method that throws an exception and drop it in the task flow.2. Adding an Exception Handler: Write a method (example below) to overwrite the Error in the bean or data control and drop the method in the task flow. Figure 3 This method is marked as the Exception Handler by Right-Click on method > Mark Activity> Exception Handler or by the button that is displayed in this screenshot Figure 4 The Final task flow should look like this. This will overwrite the exception with the error message in figure 2. Note: There is no need for a control flow between the two method calls (as shown below). Figure 5 Solution 2: Re-Routing the task flow to display an error page Figure 6 Steps to code 1. This is the same as step 1 of solution 1.2. Adding an Exception Handler: The Exception handler is not always a method; in this case it is implemented on a task flow return.  The task flow looks like this. Figure 7 In the figure below you will notice that the task flow return points to a control flow ‘error’ in the calling task flow. Figure 8 This control flow in turn goes to a view ‘error.jsff’ which contains the error message that one wishes to display.  This can be seen in the figure below. (‘withErrorHandling’ is a  call to the task flow in figure 7) Figure 9

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  • EJB Persist On Master Child Relationship

    - by deepak.siddappa(at)oracle.com
    Let us take scenario where in users wants to persist master child relationship. Here will have two tables dept, emp (using Scott Schema) which are having master child relation.Model Diagram: Here in the above model diagram, Dept is the Master table and Emp is child table and Dept is related to emp by one to n relationship. Lets assume we need to make new entries in emp table using EJB persist method. Create a Emp form manually dropping the fields, where deptno will be dropped as Single Selection -> ADF Select One Choice (which is a foreign key in emp table) from deptFindAll DC. Make sure to bind all field variables in backing bean.Employee Form:Once the Emp form created, If the persistEmp() method is used to commit the record this will persist all the Emp fields into emp table except deptno, because the deptno will be passed as a Object reference in persistEmp method  (Its foreign key reference). So directly deptno can't be passed to the persistEmp method instead deptno should be explicitly set to the emp object, then the persist will save the deptno to the emp table.Below solution is one way of work around to achieve this scenario -Create a method in sessionBean for adding emp records and expose this method in DataControl.     For Ex: Here in the below code 'em" is a EntityManager.            private EntityManager em - will be member variable in sessionEJBBeanpublic void addEmpRecord(String ename, String job, BigDecimal deptno) { Emp emp = new Emp(); emp.setEname(ename); emp.setJob(job); //setting the deptno explicitly Dept dept = new Dept(); dept.setDeptno(deptno); //passing the dept object emp.setDept(dept); //persist the emp object data to Emp table em.persist(emp); }From DataControl palette Drop addEmpRecord as Method ADF button, In Edit action binding window enter the parameter values which are binded in backing bean.     For Ex:     If the name deptno textfield is binded with "deptno" variable in backing bean, then El Expression Builder pass value as "#{backingbean.deptno.value}"Binding:

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  • Mutating Programming Language?

    - by MattiasK
    For fun I was thinking about how one could build a programming language that differs from OOP and came up with this concept. I don't have a strong foundation in computer science so it might be common place without me knowing it (more likely it's just a stupid idea :) I apologize in advance for this somewhat rambling question :) Anyways here goes: In normal OOP methods and classes are variant only upon parameters, meaning if two different classes/methods call the same method they get the same output. My, perhaps crazy idea, is that the calling method and class could be an "invisible" part of it's signature and the response could vary depending on who call's an method. Say that we have a Window object with a Break() method, now anyone (who has access) could call this method on Window with the same result. Now say that we have two different objects, Hammer and SledgeHammer. If Break need to produce different results based on these we'd pass them as parameters Break(IBluntObject bluntObject) With a mutating programming language (mpl) the operating objects on the method would be visible to the Break Method without begin explicitly defined and it could adopt itself based on them). So if SledgeHammer calls Window.Break() it would generate vastly different results than if Hammer did so. If OOP classes are black boxes then MPL are black boxes that knows who's (trying) to push it's buttons and can adapt accordingly. You could also have different permission sets on methods depending who's calling them rather than having absolute permissions like public and private. Does this have any advantage over OOP? Or perhaps I should say, would it add anything to it since you should be able to simply add this aspect to methods (just give access to a CallingMethod and CallingClass variable in context) I'm not sure, might be to hard to wrap one's head around, it would be kinda interesting to have classes that adopted themselves to who uses them though. Still it's an interesting concept, what do you think, is it viable?

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  • Matrix Multiplication with C++ AMP

    - by Daniel Moth
    As part of our API tour of C++ AMP, we looked recently at parallel_for_each. I ended that post by saying we would revisit parallel_for_each after introducing array and array_view. Now is the time, so this is part 2 of parallel_for_each, and also a post that brings together everything we've seen until now. The code for serial and accelerated Consider a naïve (or brute force) serial implementation of matrix multiplication  0: void MatrixMultiplySerial(std::vector<float>& vC, const std::vector<float>& vA, const std::vector<float>& vB, int M, int N, int W) 1: { 2: for (int row = 0; row < M; row++) 3: { 4: for (int col = 0; col < N; col++) 5: { 6: float sum = 0.0f; 7: for(int i = 0; i < W; i++) 8: sum += vA[row * W + i] * vB[i * N + col]; 9: vC[row * N + col] = sum; 10: } 11: } 12: } We notice that each loop iteration is independent from each other and so can be parallelized. If in addition we have really large amounts of data, then this is a good candidate to offload to an accelerator. First, I'll just show you an example of what that code may look like with C++ AMP, and then we'll analyze it. It is assumed that you included at the top of your file #include <amp.h> 13: void MatrixMultiplySimple(std::vector<float>& vC, const std::vector<float>& vA, const std::vector<float>& vB, int M, int N, int W) 14: { 15: concurrency::array_view<const float,2> a(M, W, vA); 16: concurrency::array_view<const float,2> b(W, N, vB); 17: concurrency::array_view<concurrency::writeonly<float>,2> c(M, N, vC); 18: concurrency::parallel_for_each(c.grid, 19: [=](concurrency::index<2> idx) restrict(direct3d) { 20: int row = idx[0]; int col = idx[1]; 21: float sum = 0.0f; 22: for(int i = 0; i < W; i++) 23: sum += a(row, i) * b(i, col); 24: c[idx] = sum; 25: }); 26: } First a visual comparison, just for fun: The beginning and end is the same, i.e. lines 0,1,12 are identical to lines 13,14,26. The double nested loop (lines 2,3,4,5 and 10,11) has been transformed into a parallel_for_each call (18,19,20 and 25). The core algorithm (lines 6,7,8,9) is essentially the same (lines 21,22,23,24). We have extra lines in the C++ AMP version (15,16,17). Now let's dig in deeper. Using array_view and extent When we decided to convert this function to run on an accelerator, we knew we couldn't use the std::vector objects in the restrict(direct3d) function. So we had a choice of copying the data to the the concurrency::array<T,N> object, or wrapping the vector container (and hence its data) with a concurrency::array_view<T,N> object from amp.h – here we used the latter (lines 15,16,17). Now we can access the same data through the array_view objects (a and b) instead of the vector objects (vA and vB), and the added benefit is that we can capture the array_view objects in the lambda (lines 19-25) that we pass to the parallel_for_each call (line 18) and the data will get copied on demand for us to the accelerator. Note that line 15 (and ditto for 16 and 17) could have been written as two lines instead of one: extent<2> e(M, W); array_view<const float, 2> a(e, vA); In other words, we could have explicitly created the extent object instead of letting the array_view create it for us under the covers through the constructor overload we chose. The benefit of the extent object in this instance is that we can express that the data is indeed two dimensional, i.e a matrix. When we were using a vector object we could not do that, and instead we had to track via additional unrelated variables the dimensions of the matrix (i.e. with the integers M and W) – aren't you loving C++ AMP already? Note that the const before the float when creating a and b, will result in the underling data only being copied to the accelerator and not be copied back – a nice optimization. A similar thing is happening on line 17 when creating array_view c, where we have indicated that we do not need to copy the data to the accelerator, only copy it back. The kernel dispatch On line 18 we make the call to the C++ AMP entry point (parallel_for_each) to invoke our parallel loop or, as some may say, dispatch our kernel. The first argument we need to pass describes how many threads we want for this computation. For this algorithm we decided that we want exactly the same number of threads as the number of elements in the output matrix, i.e. in array_view c which will eventually update the vector vC. So each thread will compute exactly one result. Since the elements in c are organized in a 2-dimensional manner we can organize our threads in a two-dimensional manner too. We don't have to think too much about how to create the first argument (a grid) since the array_view object helpfully exposes that as a property. Note that instead of c.grid we could have written grid<2>(c.extent) or grid<2>(extent<2>(M, N)) – the result is the same in that we have specified M*N threads to execute our lambda. The second argument is a restrict(direct3d) lambda that accepts an index object. Since we elected to use a two-dimensional extent as the first argument of parallel_for_each, the index will also be two-dimensional and as covered in the previous posts it represents the thread ID, which in our case maps perfectly to the index of each element in the resulting array_view. The kernel itself The lambda body (lines 20-24), or as some may say, the kernel, is the code that will actually execute on the accelerator. It will be called by M*N threads and we can use those threads to index into the two input array_views (a,b) and write results into the output array_view ( c ). The four lines (21-24) are essentially identical to the four lines of the serial algorithm (6-9). The only difference is how we index into a,b,c versus how we index into vA,vB,vC. The code we wrote with C++ AMP is much nicer in its indexing, because the dimensionality is a first class concept, so you don't have to do funny arithmetic calculating the index of where the next row starts, which you have to do when working with vectors directly (since they store all the data in a flat manner). I skipped over describing line 20. Note that we didn't really need to read the two components of the index into temporary local variables. This mostly reflects my personal choice, in some algorithms to break down the index into local variables with names that make sense for the algorithm, i.e. in this case row and col. In other cases it may i,j,k or x,y,z, or M,N or whatever. Also note that we could have written line 24 as: c(idx[0], idx[1])=sum  or  c(row, col)=sum instead of the simpler c[idx]=sum Targeting a specific accelerator Imagine that we had more than one hardware accelerator on a system and we wanted to pick a specific one to execute this parallel loop on. So there would be some code like this anywhere before line 18: vector<accelerator> accs = MyFunctionThatChoosesSuitableAccelerators(); accelerator acc = accs[0]; …and then we would modify line 18 so we would be calling another overload of parallel_for_each that accepts an accelerator_view as the first argument, so it would become: concurrency::parallel_for_each(acc.default_view, c.grid, ...and the rest of your code remains the same… how simple is that? Comments about this post by Daniel Moth welcome at the original blog.

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  • Sprites, Primitives and logic entity as structs

    - by Jeffrey
    I'm wondering would it be considered acceptable: The window class is responsible for drawing data, so it will have a method: Window::draw(const Sprite&); Window::draw(const Rect&); Window::draw(const Triangle&); Window::draw(const Circle&); and all those primitives + sprites would be just public struct. For example Sprite: struct Sprite { float x, y; // center float origin_x, origin_y; float width, height; float rotation; float scaling; GLuint texture; Sprite(float w, float h); Sprite(float w, float h, float a, float b); void useTexture(std::string file); void setOrigin(float a, float b); void move(float a, float b); // relative move void moveTo(float a, float b); // absolute move void rotate(float a); // relative rotation void rotateTo(float a); // absolute rotation void rotationReset(); void scale(float a); // relative scaling void scaleTo(float a); // absolute scaling void scaleReset(); }; So instead of having each primitive to call their draw() function, which is a little bit off topic for their object, I let the Window class handle all the OpenGL stuff and manipulate them as simple objects that will be drawn later on. Is this pattern used? Does it have any cons against it's primitives-draw-themself pattern? Are there any other related patterns?

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  • which style of member-access is preferable

    - by itwasntpete
    the purpose of oop using classes is to encapsulate members from the outer space. i always read that accessing members should be done by methods. for example: template<typename T> class foo_1 { T state_; public: // following below }; the most common doing that by my professor was to have a get and set method. // variant 1 T const& getState() { return state_; } void setState(T const& v) { state_ = v; } or like this: // variant 2 // in my opinion it is easier to read T const& state() { return state_; } void state(T const& v) { state_ = v; } assume the state_ is a variable, which is checked periodically and there is no need to ensure the value (state) is consistent. Is there any disadvantage of accessing the state by reference? for example: // variant 3 // do it by reference T& state() { return state_; } or even directly, if I declare the variable as public. template<typename T> class foo { public: // variant 4 T state; }; In variant 4 I could even ensure consistence by using c++11 atomic. So my question is, which one should I prefer?, Is there any coding standard which would decline one of these pattern? for some code see here

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  • Position Reconstruction from Depth by inverting Perspective Projection

    - by user1294203
    I had some trouble reconstructing position from depth sampled from the depth buffer. I use the equivalent of gluPerspective in GLM. The code in GLM is: template GLM_FUNC_QUALIFIER detail::tmat4x4 perspective ( valType const & fovy, valType const & aspect, valType const & zNear, valType const & zFar ) { valType range = tan(radians(fovy / valType(2))) * zNear; valType left = -range * aspect; valType right = range * aspect; valType bottom = -range; valType top = range; detail::tmat4x4 Result(valType(0)); Result[0][0] = (valType(2) * zNear) / (right - left); Result[1][2] = (valType(2) * zNear) / (top - bottom); Result[2][3] = - (zFar + zNear) / (zFar - zNear); Result[2][4] = - valType(1); Result[3][5] = - (valType(2) * zFar * zNear) / (zFar - zNear); return Result; } There doesn't seem to be any errors in the code. So I tried to invert the projection, the formula for the z and w coordinates after projection are: and dividing z' with w' gives the post-projective depth (which lies in the depth buffer), so I need to solve for z, which finally gives: Now, the problem is I don't get the correct position (I have compared the one reconstructed with a rendered position). I then tried using the respective formula I get by doing the same for this Matrix. The corresponding formula is: For some reason, using the above formula gives me the correct position. I really don't understand why this is the case. Have I done something wrong? Could someone enlighten me please?

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  • Question on methods in Object Oriented Programming

    - by mal
    I’m learning Java at the minute (first language), and as a project I’m looking at developing a simple puzzle game. My question relates to the methods within a class. I have my Block type class; it has its many attributes, set methods, get methods and just plain methods. There are quite a few. Then I have my main board class. At the moment it does most of the logic, positioning of sprites collision detection and then draws the sprites etc... As I am learning to program as much as I’m learning to program games I’m curious to know how much code is typically acceptable within a given method. Is there such thing as having too many methods? All my draw functionality happens in one method, should I break this into a few ‘sub’ methods? My thinking is if I find at a later stage that the for loop I’m using to cycle through the array of sprites searching for collisions in the spriteCollision() method is inefficient I code a new method and just replace the old method calls with the new one, leaving the old code intact. Is it bad practice to have a method that contains one if statement, and place the call for that method in the for loop? I’m very much in the early stages of coding/designing and I need all the help I can get! I find it a little intimidating when people are talking about throwing together a prototype in a day too! Can’t wait until I’m that good!

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