Implementierung des begrenzten Caches in der gleichzeitigen JAVA-Programmierung
1. Basisklasse des begrenzten Caches
package cn.xf.cp.ch14; /** * *功能:有界缓存实现基类 *时间:下午2:20:00 *文件:BaseBoundedBuffer.java *@author Administrator * * @param <V> */ public class BaseBoundedBuffer<V> { private final V[] buf; private int tail; private int head; private int count; public BaseBoundedBuffer(int capacity) { //初始化数组 this.buf = (V[]) new Object[capacity]; } //放入一个数据,final方法无法被重写 protected synchronized final void doPut(V v) { buf[tail] = v; if(++tail == buf.length) { tail = 0; } //插入一个方法,总量++ ++count; } /** * 取出一个数据 * @return */ protected synchronized final V doTake() { V v = buf[head]; buf[head] = null; if(++head == buf.length) { head = 0; } --count; return v; } //通过对count的判断,来确定数组是否是满的 public synchronized final boolean isFull() { return count == buf.length; } public synchronized final boolean isEmpty() { return count == 0; } }2 Ausführung von Operationen
package cn.xf.cp.ch14; /** * *功能:对插入和获取元素操作进行先行检查,然后执行操作,校验不通过不予操作 *时间:下午2:33:41 *文件:GrumpyBoundedBuffer.java *@author Administrator * * @param <V> */ public class GrumpyBoundedBuffer<V> extends BaseBoundedBuffer<V> { public GrumpyBoundedBuffer(int size) { super(size); } public synchronized void put(V v) throws Exception { //如果是满的队列,就无法插入新的元素 if(this.isFull()) { throw new Exception("队列超出"); } this.doPut(v); } //同理,队列为空的就无法取出新的元素 public synchronized V take() throws Exception { if(this.isEmpty()) { throw new Exception("队列中无元素"); } return this.doTake(); } }3. Implementieren Sie einfache Blockierung durch Abfragen und Ruhezustand
package cn.xf.cp.ch14; /** * *功能:通过轮询与休眠来实现简单的阻塞 *时间:下午2:55:54 *文件:SleepyBoundedBuffer.java *@author Administrator * * @param <V> */ public class SleepyBoundedBuffer<V> extends BaseBoundedBuffer<V> { //2s private static final long SLEEP_GRANULARITY = 2000; public SleepyBoundedBuffer(int capacity) { super(capacity); } //放入队列的时候 public void put(V v) throws InterruptedException { while(true) { //这里不对循环上锁,不然这个锁就无法释放了,不对休眠上锁,休眠上锁,在休眠的时候别人也无法操作,永远都不可能有元素出去 synchronized (this) { //如果队列不是满的,那么就放入元素 if(!this.isFull()) { this.doPut(v); return; } } //否则休眠,退出cpu占用 Thread.sleep(SLEEP_GRANULARITY); } } public V take() throws InterruptedException { while(true) { //这里不对循环上锁,不然这个锁就无法释放了,不对休眠上锁,休眠上锁,在休眠的时候别人也无法操作,永远都不可能有新的元素进来 synchronized(this) { //如果数组部位空,那么就可以取出数据 if(!this.isEmpty()) { return this.doTake(); } //如果队列为空,休眠几秒再试 } Thread.sleep(SLEEP_GRANULARITY); } } }4. Bedingte Warteschlange
package cn.xf.cp.ch14; /** * *功能:使用条件队列 *时间:下午3:32:04 *文件:BoundedBuffer.java *@author Administrator * * @param <V> */ public class BoundedBuffer<V> extends BaseBoundedBuffer<V> { public BoundedBuffer(int capacity) { super(capacity); } /** * 放入数据元素 * @param v * @throws InterruptedException */ public synchronized void put(V v) throws InterruptedException { while(this.isFull()) { //这里挂起程序,会释放锁 this.wait(); } //如果队列不为满的,那么程序被唤醒之后从新获取锁 this.doPut(v); //执行结束,唤醒其他队列 this.notifyAll(); } public synchronized V take() throws InterruptedException { while(this.isEmpty()) { this.wait(); } V v = this.doTake(); this.notifyAll(); return v; } }Vielen Dank fürs Lesen, ich hoffe, es kann allen helfen, vielen Dank für Ihre Unterstützung dieser Website! Ausführlichere Erläuterungen zur Implementierung des begrenzten Caches in der gleichzeitigen JAVA-Programmierung finden Sie auf der chinesischen PHP-Website!