这个示例中BoundedBuffer是一个固定长度的集合，这个在其put操作时，如果发现长度已经达到最大长度，那么会等待notFull信号，如果得到notFull信号会像集合中添加元素，并发出notEmpty的信号，而在其take方法中如果发现集合长度为空，那么会等待notEmpty的信号，同时如果拿到一个元素，那么会发出notFull的信号。
package locks; import java.util.Random;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock; public class AppOfficial { /**
* BoundedBuffer 是一个定长100的集合，当集合中没有元素时，take方法需要等待，直到有元素时才返回元素
* 当其中的元素数达到最大值时，要等待直到元素被take之后才执行put的操作
* @author yukaizhao
*
*/
static class BoundedBuffer {
final Lock lock = new ReentrantLock();
final Condition notFull = lock.newCondition();
final Condition notEmpty = lock.newCondition(); final Object[] items = new Object[100];
int putptr, takeptr, count; public void put(Object x) throws InterruptedException {
System .out.println("put wait lock");
lock.lock();
System.out.println("put get lock");
try {
while (count == items.length) {
System.out.println("buffer full, please wait");
notFull.await();
} items[putptr] = x;
if (++putptr == items.length)
putptr = 0;
++count;
notEmpty.signal();
} finally {
lock.unlock();
}
} public Object take() throws InterruptedException {
System.out.println("take wait lock");
lock.lock();
System.out.println("take get lock");
try {
while (count == 0) {
System.out.println("no elements, please wait");
notEmpty.await();
}
Object x = items[takeptr];
if (++takeptr == items.length)
takeptr = 0;
--count;
notFull.signal();
return x;
} finally {
lock.unlock();
}
}
} public static void main(String[] args) {
final BoundedBuffer boundedBuffer = new BoundedBuffer(); Thread t1 = new Thread(new Runnable() {
@Override
public void run() {
System.out.println("t1 run");
for (int i=0;i<1000;i++) {
try {
System.out.println("putting..");
boundedBuffer.put(Integer.valueOf(i));
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} }) ; Thread t2 = new Thread(new Runnable() {
@Override
public void run() {
for (int i=0;i<1000;i++) {
try {
Object val = boundedBuffer.take();
System.out.println(val);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
} }) ; t1.start();
t2.start();
}
}