java解决单缓冲生产者消费者问题示例

经典的生产者消费者问题模拟。此程序模拟最简单情形——单缓冲。为模拟实际情况，consume item和produce item时加了延时，可以通过修改延时模拟不同的生成消费速率。

[code]

[/co/**
 * single buffer consumer-producer problem.
 * by xu([e-mail]).
 * */
public class consumerproducer {

 static object buffer = null;

 static object mutex = new object();

 static object condconsumer = new object();

 static object condproducer = new object();

 public static void main(string[] args) {
  thread producer = new thread() {
   public void run() {
//    for(int i=0; i<10; i++) {
    for(int i=0; ; i++) {
     // produce item.
     try {
      thread.sleep(1000);
     } catch (interruptedexception e) {
      e.printstacktrace();
     }
     string item = new string("item-" + i);
     system.out.println("[producer] produced " + item);

     // wait for buffer empty.
     synchronized (condproducer) {
      while(buffer != null) {
       try {
        condproducer.wait();
       } catch (interruptedexception e) {
        e.printstacktrace();
       }
      }
     }

     // put item to buffer.     
     synchronized (mutex) {
      buffer = item;
      system.out.println("[producer] put " + item + " to buffer.");
     }

     // notify consumers.
     synchronized (condconsumer) {
      condconsumer.notify();
     }
    }
   }
  };

  thread consumer = new thread() {
   public void run() {
//    for(int i=0; i<10; i++) {
    for( ; ; ) {
     // wait for item come.
     synchronized (condconsumer) {
      while( buffer == null ) {
       try {
        condconsumer.wait();
       } catch (interruptedexception e) {
        e.printstacktrace();
       }
      }
     }

     // get item from buffer.
     string item = null;
     synchronized (mutex) {
      item = (string)buffer;
      buffer = null;
      system.out.println("  [consumer] get " + item + " from buffer.");
     }

     // consume item.
     try {
      thread.sleep(500);
     } catch (interruptedexception e) {
      e.printstacktrace();
     }
     system.out.println("  [consumer] comsumed " + item);

     // notify producers.
     synchronized (condproducer) {
      condproducer.notify();
     }
    }
   }
  };

  consumer.start();
  producer.start();
 }
}de]