GuardedSuspention模式主要思想是：
当条件不满足时，线程等待，直到条件满足时，等待该条件的线程被唤醒。
我们设计一个客户端线程和一个服务器线程，客户端线程不断发送请求给服务器线程，服务器线程不断处理请求。当请求队列为空时，服务器线程就必须等待，直到客户端发送了请求。
先定义一个请求队列：Queue
package com.crackj2ee.thread;
import java.util.*;
public class Queue {
private List queue = new LinkedList();
public synchronized Request getRequest() {
while(queue.size()==0) {
try {
this.wait();
}
catch(InterruptedException ie) {
return null;
}
}
return (Request)queue.remove(0);
}
public synchronized void putRequest(Request request) {
queue.add(request);
this.notifyAll();
}
}
蓝色部分就是服务器线程的等待条件，而客户端线程在放入了一个request后，就使服务器线程等待条件满足，于是唤醒服务器线程。
客户端线程：ClientThread
package com.crackj2ee.thread;
public class ClientThread extends Thread {
private Queue queue;
private String clientName;
public ClientThread(Queue queue, String clientName) {
this.queue = queue;
this.clientName = clientName;
}
public String toString() {
return "[ClientThread-" + clientName + "]";
}
public void run() {
for(int i=0; i<100; i++) {
Request request = new Request("" + (long)(Math.random()*10000));
System.out.println(this + " send request: " + request);
queue.putRequest(request);
try {
Thread.sleep((long)(Math.random() * 10000 + 1000));
}
catch(InterruptedException ie) {
}
}
System.out.println(this + " shutdown.");
}
}
服务器线程：ServerThread
package com.crackj2ee.thread;
public class ServerThread extends Thread {
private boolean stop = false;
private Queue queue;
public ServerThread(Queue queue) {
this.queue = queue;
}
public void shutdown() {
stop = true;
this.interrupt();
try {
this.join();
}
catch(InterruptedException ie) {}
}
public void run() {
while(!stop) {
Request request = queue.getRequest();
System.out.println("[ServerThread] handle request: " + request);
try {
Thread.sleep(2000);
}
catch(InterruptedException ie) {}
}
System.out.println("[ServerThread] shutdown.");
}
}
