how to get input from barcode reader in java Using notifyAll() When Many Threads May Be Waiting in Java

Printer PDF-417 2d barcode in Java Using notifyAll() When Many Threads May Be Waiting

Using notifyAll() When Many Threads May Be Waiting
PDF 417 Scanner In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
PDF417 Generator In Java
Using Barcode creator for Java Control to generate, create PDF 417 image in Java applications.
In most scenarios, it s preferable to notify all of the threads that are waiting on a particular object. If so, you can use notifyAll() on the object to let all the threads
PDF 417 Scanner In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
Drawing Barcode In Java
Using Barcode drawer for Java Control to generate, create barcode image in Java applications.
Thread Interaction (Exam Objective 7.4)
Read Barcode In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
PDF 417 Encoder In C#.NET
Using Barcode generation for VS .NET Control to generate, create PDF-417 2d barcode image in .NET applications.
rush out of the waiting area and back to runnable. This is especially important if you have threads waiting on one object, but for different reasons, and you want to be sure that the right thread gets notified.
PDF417 Maker In .NET
Using Barcode creation for ASP.NET Control to generate, create PDF417 image in ASP.NET applications.
Generate PDF417 In VS .NET
Using Barcode maker for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in Visual Studio .NET applications.
notifyAll(); // Will notify all waiting threads
PDF-417 2d Barcode Creator In VB.NET
Using Barcode printer for .NET framework Control to generate, create PDF417 image in .NET framework applications.
Painting Matrix 2D Barcode In Java
Using Barcode generation for Java Control to generate, create Matrix Barcode image in Java applications.
All of the threads will be notified and start competing to get the lock. As the lock is used and released by each thread, all of them will get into action without a need for further notification. As we said earlier, an object can have many threads waiting on it, and using notify() will affect only one of them. Which one exactly is not specified and depends on the JVM implementation, so you should never rely on a particular thread being notified in preference to another. In cases in which there might be a lot more waiting, the best way to do this is by using notifyAll(). Let s take a look at this in some code. In this example, there is one class that performs a calculation and many readers that are waiting to receive the completed calculation. At any given moment many readers may be waiting.
Create Code 39 In Java
Using Barcode drawer for Java Control to generate, create ANSI/AIM Code 39 image in Java applications.
Encode USS Code 128 In Java
Using Barcode creator for Java Control to generate, create Code-128 image in Java applications.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. class Reader extends Thread { Calculator c; public Reader(Calculator calc) { c = calc; } public void run() { synchronized(c) { try { System.out.println("Waiting for calculation..."); c.wait(); } catch (InterruptedException e) {} } System.out.println("Total is: " + c.total); } public static void main(String [] args) { Calculator calculator = new Calculator(); calculator.start(); new Reader(calculator).start(); new Reader(calculator).start(); new Reader(calculator).start(); } }
Create USPS OneCode Solution Barcode In Java
Using Barcode encoder for Java Control to generate, create OneCode image in Java applications.
Create Data Matrix ECC200 In Objective-C
Using Barcode maker for iPhone Control to generate, create Data Matrix image in iPhone applications.
9: Threads
Code 39 Extended Printer In Java
Using Barcode generator for Android Control to generate, create Code 39 image in Android applications.
Paint UPC Code In Java
Using Barcode creation for Android Control to generate, create UPC Symbol image in Android applications.
27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38.
Creating EAN 13 In None
Using Barcode printer for Excel Control to generate, create GTIN - 13 image in Excel applications.
Code 39 Extended Drawer In Objective-C
Using Barcode drawer for iPhone Control to generate, create Code 3/9 image in iPhone applications.
class Calculator extends Thread { int total; public void run() { synchronized(this) { for(int i=0;i<100;i++) { total += i; } notifyAll(); } } }
Paint Bar Code In C#
Using Barcode encoder for .NET Control to generate, create bar code image in .NET applications.
Print Barcode In Java
Using Barcode creator for Eclipse BIRT Control to generate, create bar code image in Eclipse BIRT applications.
This program starts the calculator with its calculation, and then starts three threads that are all waiting to receive the finished calculation (lines 18 24). Note that if the run() method at line 30 used notify() instead of notifyAll(), there would be a chance that only one reader would be notified instead of all the readers.
The methods wait(), notify(), and notifyAll() are methods of only java.lang.Object, not of java.lang.Thread or java.lang.Runnable. Be sure you know which methods are defined in Thread, which in Object, and which in Runnable (just run(), so that s an easy one). Of the key methods in Thread, be sure you know which are static sleep() and yield(), and which are not static join() and start(). Table 9-2 lists the key methods you ll need to know for the exam, with the static methods shown in italics.
TABLE 9-2
Class Object wait() notify() notifyAll()
Class Thread start()
Interface Runnable run()
Key Thread Methods
yield() sleep()
join()
Certification Summary
CERTIFICATION SUMMARY
This chapter covered the required thread knowledge you ll need to apply on the certification exam. Threads can be created by either extending the Thread class or implementing the Runnable interface. The only method that must be overridden in the Runnable interface is the run() method, but the thread doesn t become a thread of execution until somebody calls the Thread object s start() method. We also looked at how the sleep() method can be used to pause a thread, and we saw that when an object goes to sleep, it holds onto any locks it acquired prior to sleeping. We looked at five thread states: new, runnable, running, blocked/waiting/ sleeping, and dead. You learned that when a thread is dead, it can never be restarted even if it s still a valid object on the heap. We saw that there is only one way a thread can transition to running, and that s from runnable. However, once running, a thread can become dead, go to sleep, wait for another thread to finish, block on an object s lock, wait for a notification, or return to runnable. You saw how two threads acting on the same data can cause serious problems (remember Lucy and Fred s bank account ). We saw that to let one thread execute a method but prevent other threads from running the same object s method, we use the synchronized keyword. To coordinate activity between different threads, use the wait(), notify(), and notifyAll() methods.
Copyright © OnBarcode.com . All rights reserved.