Toy Program——線程同步。涉及wait(),notifyall(),runnable,toString

public class TestProducerConsumer {

	public static void main(String[] args) {
		SyncStack ss = new SyncStack();
		Producer pd = new Producer(ss);
		Consumer cs = new Consumer(ss);
		new Thread(pd).start();
		new Thread(pd).start();
		new Thread(pd).start();
		new Thread(cs).start();
		new Thread(cs).start();
	}

}

class SteamedBuns{
	int id = 0;
	SteamedBuns(int id){
		this.id = id;
	}
	public String toString(){
		return "SteamedBuns: " + id;
	}
}

class Producer implements Runnable{
	SyncStack sbsBuffer = null;
	Producer(SyncStack sbsBuffer){
		this.sbsBuffer = sbsBuffer;
	}
	
	public void run(){
		for(int i = 0; i < 20; i++){
			SteamedBuns sbs = new SteamedBuns(i);
			sbsBuffer.putInto(sbs);
			System.out.println("+++Produced+++ " + sbs);
			try{
				Thread.sleep(1000);
			}catch(InterruptedException ie){
				ie.printStackTrace();
			}
		}
	}
}

class Consumer implements Runnable{
	SyncStack sbsBuffer = null;
	Consumer(SyncStack sbsBuffer){
		this.sbsBuffer = sbsBuffer;
	}
	
	public void run(){
		for(int i = 0; i < 20; i++){
			SteamedBuns sbs = sbsBuffer.takeOut();
			System.out.println("--Consumed-- " + sbs);
			try{
				Thread.sleep(1000);
			}catch(InterruptedException ie){
				ie.printStackTrace();
			}
		}
	}
}
class SyncStack{
	int index = 0;
	SteamedBuns[] arrSbs = new SteamedBuns[20];
	
	public synchronized void putInto(SteamedBuns sbs){//線程鎖定與喚醒
		while(index == arrSbs.length){
			try{
				this.wait();
			}catch(InterruptedException ie){
				ie.printStackTrace();
			}
		}
		this.notifyAll();
		arrSbs[index] = sbs;
		index++;
	}
	
	public synchronized SteamedBuns takeOut(){//線程鎖定與喚醒
		while(index == 0){
			try{
				this.wait();
			}catch(InterruptedException ie){
				ie.printStackTrace();
			}
		}
		this.notifyAll();
		index--;
		return arrSbs[index];
	}
}

當線程需要阻塞式的等待時，則調用wait（）。而wait（）的同時，鎖止權不由線程控制。

sleep（）全程hold鎖止權。

wait（）搭配notify（）和notifyAll（）使用。

能用Interface的Runnable就不用class的Thread