vifix.cn

package cn.vifix.concurrentLab;
import java.util.Hashtable;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
 
public class ThreadPoolDemo
{
	public static Hashtable<Integer,String> jobs;
 
	public static void main(String[] args)
	{
		new ThreadPoolDemo();
	}
 
	public ThreadPoolDemo()
	{
		jobs = new Hashtable<Integer, String>();
		int taskCount = 30;
		for (int i=0; i<taskCount; i++)
		{
			jobs.put(i, "todo");
		}
		SynchronousQueue<Runnable> queue = new SynchronousQueue<Runnable>();
		ThreadPoolExecutor exec = new ThreadPoolExecutor(3, 3, 20, TimeUnit.SECONDS, queue, new ThreadPoolExecutor.DiscardPolicy());
		while(jobs.size() > 0)
		{
			try
			{
				Thread.sleep(500);
			}
			catch (Exception e)
			{
				e.printStackTrace();
			}
			if (exec.getActiveCount() == 3)
			{
				System.out.println("Thread count == 3; Skip this loop...");
				continue;
			}
			for (int i = taskCount - 1; i > -1; i--)
			{
				if (jobs.containsKey(i))
				{
					if (jobs.get(i) == "todo")
					{
						jobs.put(i, "doing");
						exec.execute(new ThreadPoolDemoWorker(i));
						break;
					}
				}
			}
			synchronized(System.out)
			{
				System.out.print(jobs.size());
				System.out.print(" Task Left:");
				System.out.print(" List:");
				System.out.println(jobs);
			}
		}
		System.out.println("All done.");
		System.exit(0);
	}
}

package cn.vifix.concurrentLab;
 
public class ThreadPoolDemoWorker implements Runnable
{
	private int idx;
 
	@Override
	public void run()
	{
		try
		{
			new ThreadPoolDemoJob(idx).process();
		}
		catch (Exception e)
		{
			System.out.println(e);
		}
	}
 
	public ThreadPoolDemoWorker(int i)
	{
		idx = i;
	}
}

package cn.vifix.concurrentLab;
import java.util.Random;
 
public class ThreadPoolDemoTask
{
	private int idx;
	private Random random;
 
	public ThreadPoolDemoTask(int i)
	{
		idx = i;
		random = new Random();
	}
	public void process() throws Exception
	{
		try
		{
			Thread.sleep(random.nextInt(10000));
		}
		catch (InterruptedException ex)
		{
			ex.printStackTrace();
		}
		this.doTask();
	}
 
	private void doTask() throws Exception
	{
		if (random.nextFloat() > 0.8)
		{
			ThreadPoolDemo.jobs.put(idx, "todo");
			synchronized(System.out)
			{
				System.out.println(" Task " + idx + " failed.");
			}
			throw new Exception("Task " + Integer.toString(idx) + " failed, retry.");
		}
		else
		{
			synchronized(System.out)
			{
				System.out.println(" Task " + idx + " done.");
			}
			ThreadPoolDemo.jobs.remove(idx);
		}
	}
}