semaphore.java

这是操作系统的程序设计

/**
 * 此类用来模拟信号量
 *
 */
public class Semaphore{
	private int semValue;
	public Semaphore(int semValue){
		this.semValue = semValue;		 
	}
	public synchronized void p(){
		semValue--;
		if(semValue<0){
			try {
				this.wait();
			} catch (InterruptedException e) {				
				e.printStackTrace();
			}
		}
	}
	public synchronized void v(){
		semValue++;
		if(semValue<=0){
			this.notify();
		}		
	}
}