Thread Pool design

Question

I have one service that processes messages, now I want it to run it in multi threads so it can execute faster. Now my question is how can I make thread pool- what is best design. Since I dont want to create n number of thereads to process n number of messages, I should create thread pool with predefined number of threads.
So my main program will do something like this
1)Check thread pool - if available
2)If available create tak and execute
3)If not wait (how to wait???)
4)Once thread has done it should be available for next processing if requred.
Thanks in advance.

Answer 1

I am not using put, I am not directly using array queue, what I understand is like its for its internal use. Here is what I am trying with,
Thread pool  class
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
public class MyThreadPool extends ThreadPoolExecutor {
     public MyThreadPool(int corePoolSize, int maximumPoolSize, long keepAliveTime,
               TimeUnit unit, BlockingQueue<Runnable> queue) {
          super(corePoolSize, maximumPoolSize, keepAliveTime, unit, queue);
Thread- Runnable object
public class MyThread implements Runnable{
     public void run() {
          System.out.println("This is MyThread running...");
          try {
               Thread.currentThread().sleep(1*5*1000);
               System.out.println("Complted...");
          } catch (InterruptedException e) {
               e.printStackTrace();
Main program
public class MyClient {
     public static void main(String[] args) {
          ArrayBlockingQueue queue = new ArrayBlockingQueue(5, false);
          MyThreadPool myThreadPool = new MyThreadPool(5, 5, 1, TimeUnit.SECONDS, queue);
          for (int i = 0; i < 6; i++) {
               MyThread t = new MyThread();
               if(myThreadPool.getTaskCount() != 1)
                    myThreadPool.submit(t);
}now see my queue size is 5 and I am submitting 6 jobs to execute. When I run main class, it runs all jobs and program never terminates.
Output:
This is MyThread running...
This is MyThread running...
This is MyThread running...
This is MyThread running...
This is MyThread running...
Complted...
This is MyThread running...
Complted...
Complted...
Complted...
Complted...
Complted...
Edited by: Miral on Apr 8, 2009 2:16 PM
Edited by: Miral on Apr 8, 2009 2:17 PM
Edited by: Miral on Apr 8, 2009 2:17 PM