threadpool.java

21天学通java的示例程序源代码

//ThreadPool.java

package com.wrox.threadpool;

import java.util.*;

public class ThreadPool {

  private Vector freeThreads = new Vector();
  private Vector inUseThreads = new Vector();

  private static int INITIAL_SIZE = 10;

  public ThreadPool() {
    fillPool(INITIAL_SIZE);
  }

  private void fillPool(int poolSize) {
    for (int i = 0; i < poolSize; i++) {
      PoolableThread pt = new PoolableThread(this);
      pt.start();
      freeThreads.add(pt);
    } 
    try {
      Thread.sleep(2000);
    } catch (InterruptedException ie) {}
  } 

  /**
   * Allocates a thread and starts this Runnable task.
   * @param task the task to run.
   */
  public synchronized void runTask(Runnable task) {
    if (freeThreads.isEmpty()) {
      throw new RuntimeException("All threads are in use");
    } 
    PoolableThread t = (PoolableThread) freeThreads.remove(0);
    inUseThreads.add(t);
    t.setTask(task);
  } 

  synchronized void free(PoolableThread t) {
    inUseThreads.remove(t);
    freeThreads.add(t);
  } 

}