barcode generator in c# code project USING THREADS AND MEDIA in Font

Generate Data Matrix in Font USING THREADS AND MEDIA

CHAPTER 4 USING THREADS AND MEDIA
Data Matrix 2d Barcode Creator In None
Using Barcode printer for Font Control to generate, create DataMatrix image in Font applications.
www.OnBarcode.com
Barcode Generator In None
Using Barcode maker for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
in Listing 4-1). In this example, when returning from a system-initiated pause, you set the game to the state of being in a user-initiated pause. The reason for this is that it may take a second for the user to be ready to return to play at the end of a call, so the game should be paused until the user is ready to unpause it. On the emulator, you can use the F6 and F7 keys to test whether you ve implemented your pause/resume functionality correctly. Listing 4-5 shows the added and modified parts of JumpCanvas.java. Listing 4-5. Additions and Changes to JumpCanvas.java //----------------------------------------------------// gets/sets /** * This is called when the game ends. */ void setGameOver() { myGameOver = true; myJump.userPauseThreads(); } /** * @return a handle to the tumbleweed objects. */ Tumbleweed[] getTumbleweeds() { return(myManager.getTumbleweeds()); } //----------------------------------------------------// initialization and game state changes /** * pause the game when it's hidden. */ protected void hideNotify() { try { myJump.systemPauseThreads(); } catch(Exception oe) { myJump.errorMsg(oe); } } /** * When it comes back into view, unpause it. */ protected void showNotify() { try { myJump.systemStartThreads(); } catch(Exception oe) {
Encoding Barcode In None
Using Barcode creation for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
Make Code-39 In None
Using Barcode drawer for Font Control to generate, create ANSI/AIM Code 39 image in Font applications.
www.OnBarcode.com
CHAPTER 4 USING THREADS AND MEDIA
Making PDF 417 In None
Using Barcode generation for Font Control to generate, create PDF 417 image in Font applications.
www.OnBarcode.com
Painting Code 128 Code Set B In None
Using Barcode generation for Font Control to generate, create Code-128 image in Font applications.
www.OnBarcode.com
myJump.errorMsg(oe); } }
UPCA Encoder In None
Using Barcode encoder for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
MSI Plessey Creator In None
Using Barcode drawer for Font Control to generate, create MSI Plessey image in Font applications.
www.OnBarcode.com
Avoiding Race Conditions and Deadlock
Data Matrix Printer In Visual Basic .NET
Using Barcode generator for Visual Studio .NET Control to generate, create Data Matrix 2d barcode image in Visual Studio .NET applications.
www.OnBarcode.com
DataMatrix Printer In None
Using Barcode drawer for Software Control to generate, create DataMatrix image in Software applications.
www.OnBarcode.com
Synchronization issues are some of the hardest problems to locate and debug. This is because the errors they create are often rare and almost impossible to reproduce. You therefore have to do all your thread synchronization debugging by pure thought. To give you an idea of how to do it, I ll go over using the synchronized keyword in this example program and suggest how to keep your program thread safe. This section will contain nothing new for experienced Java programmers, but because keeping your program thread safe is at once tricky and important, I ll include this material for those readers who are new to it. Recall the basics of how synchronization works: each instance of an object has a lock, and each class has a lock for its static methods. Suppose the instance is called myObject. If a thread enters a method for that instance marked with the synchronized keyword or if the thread enters a block of code contained in a block delineated by synchronized(myObject), then the thread picks up the instance s lock. If one thread is holding the lock for a particular instance, no other thread can enter any method or synchronized block for that particular instance until the thread currently holding the lock exits the synchronized method or block. This is a means of preventing race conditions in which two or more threads are at risk of modifying and/or acting on the values of data simultaneously. Clearly there are going to be problems if one thread completes the phrase if(x == y) and then another thread changes the value of x before the first thread executes all the statements in the if block. Obviously, the problem arises when two or more threads are using the same data at the same time and at least one of those threads might modify that data. A naive solution is to use the synchronized keyword on every method that reads or modifies data. That would force all the threads to take turns using data-related methods. But that strategy would almost certainly lead to frequent deadlock, which is when two threads get stuck because each one is waiting for the other to give up a lock. The best strategy is to analyze each class, method by method, to see where synchronization is needed and where it isn t. That s not as terrible as it sounds since it becomes second nature once you re used to doing it. Here are a few little tips: Use local method variables instead of class fields when you can because this avoids the necessity of making the method synchronized (local method variables can t be altered by other threads). Make each synchronized segment as small and simple as possible. Try to avoid grabbing a second lock from within a synchronized section. You ll now see how these ideas apply to GameThread. Using synchronization in the other two thread classes is nearly identical to how you use it in GameThread. The run() method has two synchronized blocks and two other synchronized methods. Listing 4-6 shows what they look like.
Drawing PDF-417 2d Barcode In Visual Basic .NET
Using Barcode creator for .NET Control to generate, create PDF 417 image in .NET framework applications.
www.OnBarcode.com
Code 128 Code Set A Printer In None
Using Barcode generation for Software Control to generate, create Code 128C image in Software applications.
www.OnBarcode.com
Barcode Creator In Java
Using Barcode maker for BIRT reports Control to generate, create Barcode image in BIRT reports applications.
www.OnBarcode.com
Barcode Generator In .NET
Using Barcode creator for ASP.NET Control to generate, create Barcode image in ASP.NET applications.
www.OnBarcode.com
Barcode Generation In None
Using Barcode generator for Microsoft Excel Control to generate, create Barcode image in Office Excel applications.
www.OnBarcode.com
UCC - 12 Encoder In Objective-C
Using Barcode drawer for iPad Control to generate, create UPC-A Supplement 2 image in iPad applications.
www.OnBarcode.com
Decoding QR Code In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Generating Barcode In None
Using Barcode maker for Software Control to generate, create Barcode image in Software applications.
www.OnBarcode.com
Data Matrix Drawer In None
Using Barcode printer for Microsoft Excel Control to generate, create Data Matrix image in Microsoft Excel applications.
www.OnBarcode.com
UPC A Drawer In Java
Using Barcode encoder for Java Control to generate, create UPCA image in Java applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.