栈队列

import java.util.Stack;

import org.apache.log4j.Logger;

import com.ctis.ta.util.PropertiesUtils;

/**
 * java 栈队列
 * @author 
 *
 */
public class ActiveQueue {
	public  static Logger log = Logger.getLogger(ActiveQueue.class);
	 private  static Stack _queue;
	 private  static ActiveQueue activeQueue;
	 //private final static int QUEUE_SIZE = 100;
	 private final static int QUEUE_SIZE = PropertiesUtils.getQueueSizeNum();
	 
	 private ActiveQueue() {
       
     }
	 public static ActiveQueue getInstance(){
		 if(null==_queue){
			 _queue = new Stack();
			 activeQueue = new ActiveQueue();
		 }
		 return activeQueue;
	 }
	 
     public synchronized int enqueue() {
        while(_queue.size() >= QUEUE_SIZE) {
            try {
                 wait(2000);
            }catch (InterruptedException e) {
                 log.error(this, e);
            }   
        }
        _queue.push(new Object());
        notifyAll();
        log.info("enqueue-->"+_queue.size());
        log.info("QUEUE_SIZE-->"+QUEUE_SIZE);
        return 1;
    }
    public synchronized void dequeue() {
        while(_queue.empty()) {
            try {
                wait();
            }catch (InterruptedException e) {
                log.error(this, e);
            }
        }
        _queue.pop();
        notifyAll();
        log.info("dequeue-->"+_queue.size());
    } 
}