threadpool.java

network management, thread implement

// Developed by Kinva Network Inc. 2000


// Source File Name:   ThreadPool.java

package com.kinva.util.thread;

import java.io.PrintStream;

// Referenced classes of package com.kinva.util.thread:
//            DefaultPoolThread, ThreadPoolEntry, PoolThread

public class ThreadPool
{

    public ThreadPool()
    {
        killed = false;
    }

    public synchronized void addThread(PoolThread poolthread)
    {
        if(!killed)
        {
            ThreadPoolEntry threadpoolentry = new ThreadPoolEntry(this, poolthread);
            insertIdle(threadpoolentry);
            threadpoolentry.init();
        }
    }

    public void addThread(PoolThread apoolthread[])
    {
        for(int i = apoolthread.length; --i >= 0;)
            addThread(apoolthread[i]);

    }

    public void addThread(Runnable runnable)
    {
        addThread(((PoolThread) (new DefaultPoolThread(runnable))));
    }

    public synchronized ThreadPoolEntry getEntry(boolean flag)
    {
        ThreadPoolEntry threadpoolentry;
        for(threadpoolentry = idleList; threadpoolentry == null;)
            if(flag)
            {
                acquire();
                threadpoolentry = idleList;
            } else
            {
                return null;
            }

        idleList = threadpoolentry.next;
        if(idleList != null)
            idleList.prev = null;
        threadpoolentry.next = null;
        threadpoolentry.prev = null;
        insertBusy(threadpoolentry);
        return threadpoolentry;
    }

    public synchronized ThreadPoolEntry getEntry()
    {
        return getEntry(false);
    }

    public PoolThread getThread(boolean flag)
    {
        ThreadPoolEntry threadpoolentry = getEntry(flag);
        if(threadpoolentry != null)
            return threadpoolentry.getThread();
        else
            return null;
    }

    public PoolThread getThread()
    {
        return getThread(false);
    }

    protected synchronized void acquire()
    {
        while(idleList == null) 
            try
            {
                wait();
            }
            catch(InterruptedException interruptedexception)
            {
                interruptedexception.printStackTrace();
            }
    }

    synchronized void insertIdle(ThreadPoolEntry threadpoolentry)
    {
        if(busyList == threadpoolentry)
            busyList = busyList.next;
        if(threadpoolentry.next != null)
            threadpoolentry.next.prev = threadpoolentry.prev;
        if(threadpoolentry.prev != null)
            threadpoolentry.prev.next = threadpoolentry.next;
        threadpoolentry.next = null;
        threadpoolentry.prev = null;
        if(reClaim(threadpoolentry) || killed)
        {
            System.out.println("Reclaiming " + threadpoolentry.getThread());
            threadpoolentry.shutdown();
            return;
        }
        if(idleList == null)
        {
            idleList = threadpoolentry;
        } else
        {
            threadpoolentry.next = idleList;
            idleList.prev = threadpoolentry;
            idleList = threadpoolentry;
        }
        notifyAll();
    }

    protected boolean reClaim(ThreadPoolEntry threadpoolentry)
    {
        return false;
    }

    private void insertBusy(ThreadPoolEntry threadpoolentry)
    {
        if(busyList == null)
        {
            busyList = threadpoolentry;
            return;
        } else
        {
            threadpoolentry.next = busyList;
            busyList.prev = threadpoolentry;
            busyList = threadpoolentry;
            return;
        }
    }

    public synchronized void shutdown(boolean flag)
    {
        killed = true;
        for(; idleList != null; idleList = idleList.next)
            idleList.shutdown();

        if(!flag)
            return;
        for(; busyList != null; busyList = busyList.next)
            busyList.shutdown();

    }

    public synchronized int getBusyListCount()
    {
        ThreadPoolEntry threadpoolentry = busyList;
        int i;
        for(i = 0; threadpoolentry != null; i++)
            threadpoolentry = threadpoolentry.next;

        return i;
    }

    private ThreadPoolEntry idleList;
    private ThreadPoolEntry busyList;
    private boolean killed;
}