【JAVA-CONCURRENT】 利用SEMAPHORE 实现有界阻塞容器

package concurrentTest;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;
//有界容器
public class BoundedSet {

    private final Set set;
    private final Semaphore sem;
    
    public BoundedSet(int bound){
        this.set = Collections.synchronizedSet(new HashSet());
        sem = new Semaphore(bound);
    }
    
    public Set getSet() {
        return set;
    }

    public boolean add(T o) throws InterruptedException{
        
        sem.acquire();
        boolean wasAdded = false;
        try{
            wasAdded = set.add(o);
            return wasAdded;
        }finally{
            if(!wasAdded)
                sem.release();
        }
    }
    
    public boolean remove(Object o){
        boolean wasRemoverd = set.remove(o);
        if(wasRemoverd)
            sem.release();
        return wasRemoverd;
    }
    
    class ThreadFactoryDemo implements ThreadFactory{
        
        private boolean isDeamon;
        private String threadName;
        private AtomicInteger inc = new AtomicInteger(0);
        
        public ThreadFactoryDemo(boolean isDeamon,String threadName){
            this.isDeamon = isDeamon;
            this.threadName = threadName;
        }
        
        @Override
        public Thread newThread(Runnable r) {
            Thread t = new Thread(r);
            t.setDaemon(this.isDeamon);
            t.setName(this.threadName + inc.getAndIncrement());
            return t;
        }
    }
    
    class RunnableDemo implements Runnable{
        
        private  int i;
        private  BoundedSet test;
        public RunnableDemo(int i,BoundedSet test){
            this.i = i;
            this.test = test;
        }
        
        @Override
        public void run() {
            try {
                test.add(i);
                System.out.println("Set add something already!" + Thread.currentThread().getName() + " Now set content =" + test.getSet().toString());
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }
    
    class RemoveRunnableDemo implements Runnable{
        
        private  int i;
        private  BoundedSet test;
        public RemoveRunnableDemo(int i,BoundedSet test){
            this.i = i;
            this.test = test;
        }
        
        @Override
        public void run() {
            
            while(!test.remove(i));
            System.out.println("Set remove something already! Now set content =" + test.getSet().toString());
        }
    }
    
    public static void main(String[] args) {
        
        int boundSize = 5;
        final int[] array = {0,1,2,3,4,5};
        final BoundedSet test = new BoundedSet(boundSize);
        ExecutorService executor = Executors.newFixedThreadPool(boundSize+1,test.new ThreadFactoryDemo(true,"semaphore-thread-"));
        for(int i=0;i){
            executor.execute(test.new RunnableDemo(array[i],test));
        }
        sleep(1000);
        Thread thread = new Thread(test.new RemoveRunnableDemo(array[0],test));
        thread.setName("remove task");
        thread.setDaemon(false);
        thread.start();
    }
    
    private static void sleep(int time){
        
        try {
            Thread.sleep(time);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }
}

 虽然测试打印语句会出现延迟导致输出错误，但实现是对的。 

转载于:https://www.cnblogs.com/lixusign/archive/2012/04/25/2469454.html