使用信号量semaphore实现一个无界线程池

Semaphore 用法 在调用accquire之后到release之间，别的线程会阻塞，当然前提是信用量已经没有可用的了。

package com.citi.test.mutiplethread.demo08;

import java.util.concurrent.Executor;
import java.util.concurrent.Semaphore;

public class BoundedExecutor {
    private final Executor exec;
    private final Semaphore semaphore;
    public BoundedExecutor(Executor exec,int bound) {
        this.exec=exec;
        this.semaphore=new Semaphore(bound);
    } 
    public void submitTask(final Runnable runnable) throws InterruptedException{
        //获取一个许可 在acquire之后如果信号量已经没有了，那么下个线程再进来会等待，直到有线程调用release方法
        semaphore.acquire();
        try {
            exec.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        runnable.run();
                    }finally{
                        semaphore.release();
                    }
                }
            });
        } catch (Exception e) {
            semaphore.release();
        }
    }
}