package com.maven.info.semaphore;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.Semaphore;

import java.util.concurrent.locks.Condition;

import java.util.concurrent.locks.ReentrantLock;

/**

 * @program:

 * @description:

 * @author: 刘小品

 * @create: 2019-06-20 10:38

 */

public class ListPoolDemo {

/*    可以有效的对并发执行任务的线程数进行限制，

    这种功能可以应用在pool线程池技术中，

    可以设置同时访问pool池中的数据的线程数量*/

    private int poolMaxSize = 3;

    private int semaphorePermits =5;

    private List<String>  list = new ArrayList<>();

    private Semaphore concurrencySemaphore = new Semaphore(10);

    private ReentrantLock lock = new ReentrantLock();

    private Condition condition = lock.newCondition();

    public ListPoolDemo(){

        for (int i=0;i<poolMaxSize;i++){

            list.add("superman_"+i);

        }

    }

    public String get(){

        String getString =null;

        try {

            concurrencySemaphore.acquire();

            lock.lock();

            while (list.size()==0){

                condition.await();

            }

            getString = list.remove(0);

            lock.unlock();

        }catch (Exception e){

            e.printStackTrace();

        }

        return getString;

    }

    public void put(String StringValue){

        lock.lock();

        list.add(StringValue);

        condition.signalAll();

        lock.unlock();

        concurrencySemaphore.release();

    }