Observer 模式

1.观察者：

 

package com.bian.obser;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

public class ClassObserver implements PropertyChangeListener {

 public void propertyChange(PropertyChangeEvent evt) {
  // TODO Auto-generated method stub
   if(evt.getPropertyName().equals("ClassObject.name")){
    //观察到 监视的对象发生改变。
    System.out.println("observer object changed ");
    System.out.println(evt.getPropertyName());
    System.out.println(evt.getNewValue());
    System.out.println(evt.getOldValue());
    System.out.println(evt.getPropagationId());
    System.out.println(evt.getSource().toString());
   }
 }

}

2.被观察者：

package com.bian.obser;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;

public class ClassObject {

 protected String name="xiwei";
 protected String sex;

 protected PropertyChangeSupport listenerSupport = new PropertyChangeSupport(this);

 public String getSex() {
  return sex;
 }

 public void setSex(String sex) {
  firePropertyChange("ClassObject.sex", this.sex, sex);
  this.sex = sex;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  firePropertyChange("ClassObject.name", this.name, name);
  this.name = name;
 }

 public void addPropertyChangeListener(PropertyChangeListener listener) {
  listenerSupport.addPropertyChangeListener(listener);
 }

 public void firePropertyChange(String propName, Object oldValue,Object newValue) {
  listenerSupport.firePropertyChange(propName, oldValue, newValue);
 }
 
 public void removePropertyChangeListener(PropertyChangeListener listener) {
  listenerSupport.removePropertyChangeListener(listener);
 }
}

3.测试类：

 

package com.bian.obser;

public class ClassTest {

 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  ClassObserver cOberser = new ClassObserver();
  ClassObject cObject = new ClassObject();
  
  cObject.addPropertyChangeListener(cOberser);
  cObject.setName("bianstutao");
  cObject.setSex("male");
 }

}