今天看了些Exchanger的资料,有个喝水的例子不错。我这里细化了以下,并得到实现。
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思路:
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???? 有一个Drinker和一个Waiter,有两个杯子,一个空杯子,一个杯子有3升水,Drinker一次喝1升水,要耗时1秒,Waiter一次可以倒1升水,一次耗时1秒。开始时,他们各持一个杯子,Drinker持有3升水的杯子,Waiter持有空杯子。然后开始喝水,当有一个杯子里没水了,整个程序结束。
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方法:
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???? Exchanger主要用于交换两个线程的同类型的共享数据,喝水这个例子很好的表现了Exchanger的作用。
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【注:】程序中的数据可以自己调整来,整体体现了动态交换杯子的效果。
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import java.util.concurrent.Exchanger;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.TimeUnit;class Cup { int waterVolume = 0; String cupName=""; public String getCupName() { return cupName; } public void setCupName(String cupName) { this.cupName = cupName; } Cup(int i ,String name){ waterVolume=i; cupName=name; } @Override public String toString() { // TODO Auto-generated method stub return cupName+"有"+waterVolume+"升水!"; } public int getWaterVolume() { return waterVolume; } public void drinkWater(){ waterVolume--; } public void drinkWater( int i ){ if((waterVolume-i)>=0){ waterVolume-=i; }else{ System.out.println("没有这么多水可以喝!!!"); return; } } public void addWater(){ waterVolume++; } public void addWater(int i){ waterVolume=i; }}class Drinker implements Runnable{ Cup currentCup; Exchanger ex; Drinker(Exchanger ex,Cup c){ currentCup= c; this.ex= ex; } @Override public void run() { //得到杯子喝水 /*try { currentCup = (Cup)ex.exchange(currentCup); } catch (InterruptedException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }*/ boolean flag = true; while(flag){ if(currentCup.getWaterVolume() > 0){ System.out.println("喝水者:"+currentCup); System.out.println("喝水者:从"+currentCup.getCupName()+"喝2升水,喝水用时1秒"); currentCup.drinkWater(2); try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { // TODO: handle exception e.printStackTrace(); } } if(currentCup.getWaterVolume() == 0){ System.out.println("喝水者:"+currentCup+",水喝光了!别加了!"); flag=false; } //服务员加完水后的杯子 try { currentCup = (Cup)ex.exchange(currentCup); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }class Waiter implements Runnable{ Cup currentCup; Exchanger ex; Waiter(Exchanger ex,Cup c){ currentCup= c; this.ex= ex; } @Override public void run() { //得到杯子加水 /*try { currentCup = (Cup)ex.exchange(currentCup); } catch (InterruptedException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }*/ boolean flag = true; while(flag){ System.out.println("服务员:"+currentCup); System.out.println("服务员:倒入"+currentCup.getCupName()+" 1升水,耗时1秒"); try { TimeUnit.SECONDS.sleep(1); } catch (InterruptedException e) { // TODO: handle exception e.printStackTrace(); } currentCup.addWater(); //得到顾客递过来的杯子 try { currentCup=(Cup)ex.exchange(currentCup); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(currentCup.getWaterVolume() == 0){ System.out.println("服务员:"+currentCup+"水喝光了!!不加了!"); flag=false; } } }}public class DrinkWaterDemo { public static void main(String[] args) { Cup cup1 = new Cup(3,"cup1"); Cup cup2 = new Cup(0,"cup2"); final Exchanger<Cup> ec = new Exchanger<Cup>(); ExecutorService es = Executors.newFixedThreadPool(2); es.submit(new Waiter(ec,cup2)); es.submit(new Drinker(ec, cup1)); es.shutdown(); }}
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