Inter-Thread CommunicationJava provides a very efficient way through which multiple-threads can communicate with each-other. This way reduces the CPU?s idle time i.e. A process where, a thread is paused running in its critical region and another thread is allowed to enter (or lock) in the same critical section to be executed. This technique is known as Interthread communication which is implemented by some methods. These methods are defined in "java.lang" package and can only be called within synchronized code shown as:
|wait( )||It indicates the calling thread to give up the monitor and go to sleep until some other thread enters the same monitor and calls method notify() or notifyAll().|
|notify( )||It wakes up the first thread that called wait() on the same object.|
|notifyAll( )|| Wakes up (Unloack) all the
threads that called wait( ) on the same object. The highest
priority thread will run first.
Lets see an example implementing these methods :
synchronizedmethods of the class "Shared". At time of program execution, the "put( )" method is invoked through the "Producer" class which increments the variable "num" by 1. After producing 1 by the producer, the method "get( )" is invoked by through the "Consumer" class which retrieves the produced number and returns it to the output. Thus the Consumer can't retrieve the number without producing of it.
Download this Program
Another program demonstrates the uses of wait() & notify() methods:
Demo1 value is20
value is :40