ProduceQueue；支持堵塞和非堵塞

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package com.example.zhanghaohao089.mytest;import java.util.concurrent.TimeUnit;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * 实现一个消费队列,有堵塞和非堵塞方法 * * @author ZHANGHAOHAO * @date 2017/5/11 */public class ProduceQueue<T> {    private T[] items = null;    private int head;//头部    private int last;//尾部    private Lock lock = new ReentrantLock();    private Condition notFull = lock.newCondition();    private Condition notEmpty = lock.newCondition();    private int count;//目前的count    private int max;//最大内容    public ProduceQueue() {        this(10);    }    public ProduceQueue(int max) {        items = (T[])new Object[max];        this.max = max;    }    //堵塞的    public void put(T item) {        lock.lock();        try {            if (count == max) {                notFull.await();            }            enqueue(item);            notEmpty.signalAll();            count++;        }catch (Exception e) {            e.printStackTrace();        }finally {            lock.unlock();        }    }    //非堵塞的    public boolean offer(T item) {        lock.lock();        try {            if (count == max) {                return false;            }            enqueue(item);            notEmpty.signalAll();            count++;        } catch (Exception e) {            e.printStackTrace();        } finally {            lock.unlock();        }        return true;    }    //只堵塞一定时间    public boolean offer(T item, long timeout, TimeUnit unit) {        lock.lock();        long nanos = unit.toNanos(timeout);        try {            if (count == max) {                if (nanos <= 0)                    return false;                notFull.awaitNanos(nanos);            }            enqueue(item);            notEmpty.signalAll();            count++;        } catch (Exception e) {            e.printStackTrace();        }finally {            lock.unlock();        }        return true;    }    //非堵塞的    public T poll() {        T item = null;        lock.lock();        try {          if (count == 0) {                return null;            }            item = dequeue();            notFull.signalAll();            count --;        } catch (Exception e) {            e.printStackTrace();        } finally {            lock.unlock();        }        return item;    }    //非堵塞的    public T poll(long timeout, TimeUnit unit) {        T item = null;        lock.lock();        long nanos = unit.toNanos(timeout);        try {            if (count == 0) {                if (nanos <= 0)                    return null;                notEmpty.awaitNanos(nanos);            }            item = dequeue();            notFull.signalAll();            count --;        } catch (Exception e) {            e.printStackTrace();        } finally {            lock.unlock();        }        return item;    }    //堵塞的    public T take() {        T item = null;        lock.lock();        try {            if (count == 0) {                notEmpty.await();            }            item = dequeue();            notFull.signalAll();            count --;        } catch (Exception e) {            e.printStackTrace();        } finally {            lock.unlock();        }        return item;    }    //入队列操作    private void enqueue(T item) {        if (last == max) {            last = 0;        }        items[last++] = item;    }    //出队列操作    private T dequeue() {        T item = items[head];        items[head] = null;        if (++head == max) {            head = 0;        }        return item;    }    public int getSize() {        return count;    }}
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