/**
			 * If this object has changed, as indicated by the
			 * <code>hasChanged</code> method, then notify all of its
			 * observers and then call the <code>clearChanged</code> method to
			 * indicate that this object has no longer changed.
			 * <p>
			 * Each observer has its <code>update</code> method called with
			 * two arguments: this observable object and the <code>arg</code>
			 * argument.
			 * 
			 * @param arg
			 *            any object.
			 * @see java.util.Observable#clearChanged()
			 * @see java.util.Observable#hasChanged()
			 * @see java.util.Observer#update(java.util.Observable,
			 *      java.lang.Object)
			 */
	    public void notifyObservers(Object arg) {
		/*
		 * a temporary array buffer, used as a snapshot of the state of current
		 * Observers.
		 */
	        Object[] arrLocal;
 
		synchronized (this) {
		    /*
			 * We don‘t want the Observer doing callbacks into arbitrary code
			 * while holding its own Monitor. The code where we extract each
			 * Observable from the Vector and store the state of the Observer
			 * needs synchronization, but notifying observers does not (should
			 * not). The worst result of any potential race-condition here is
			 * that: 1) a newly-added Observer will miss a notification in
			 * progress 2) a recently unregistered Observer will be wrongly
			 * notified when it doesn‘t care
			 */
		    if (!changed)
	                return;
	            arrLocal = obs.toArray();
	            clearChanged();
	        }
 
	        for (int i = arrLocal.length-1; i>=0; i--)
	            ((Observer)arrLocal[i]).update(this, arg);
	    }

/**
 *
 * @(#) AbnormalObserver.java
 * @Package pattern.chp05.observer.demo
 * 
 * Copyright ? JING Corporation. All rights reserved.
 *
 */
 
package pattern.chp05.observer.demo;
 
import java.util.Observable;
import java.util.Observer;
 
/**
 * 类描述：异常数据观察者
 * 
 * @author: Jing
 * @version $Id: Exp$
 * 
 * History: Dec 23, 2014 10:31:08 AM Jing Created.
 * 
 */
public class AbnormalObserver implements Observer {
 
	private int c = 0;// 温度异常数累计
 
	public void update(Observable o, Object arg) {
 
		Subject subject = (Subject) o;
		Factor factor = (Factor) arg;
 
		if (subject.getData() < factor.getLimie()) {// 小于预警值，则异常级数归0
 
			c = 0;
			return;
		}
		c++;
 
		if (c == factor.getTimes()) {// 符合预警次数
 
			// some code 预警
 
			c = 0;// 计数清零
		}
 
	}
 
}