java.beans.PropertyChangeListener

 1 import java.beans.PropertyChangeEvent;
 2 import java.beans.PropertyChangeListener;
 3 import java.beans.PropertyChangeSupport;
 4 
 5 public class DemoBeans {  
 6   
 7     private String demoName;  
 8     private String Version;    
 9     PropertyChangeSupport listeners = new PropertyChangeSupport(this);  
10   
11     public DemoBeans() {  
12         demoName = "initValue";  
13         Version="v1000";
14     }  
15   
16   
17     public String getDemoName() {  
18         return demoName;  
19     }  
20       
21   
22     public void setDemoName(String demoName) {  
23         String oldValue = this.demoName;  
24         this.demoName = demoName;  
25         //发布监听事件  
26         firePropertyChange("demoName", oldValue, demoName);  
27           
28     }  
29       
30     public void setDemoVersion(String demoVersion) {  
31         String oldVersion = this.Version;  
32         this.Version = demoVersion;  
33         //发布监听事件  
34         firePropertyChange("demoVersion", oldVersion, demoVersion);  
35           
36     }  
37     public void addPropertyChangeListener(PropertyChangeListener listener) {  
38         listeners.addPropertyChangeListener(listener);  
39     }  
40       
41     public void removePropertyChangeListener(PropertyChangeListener listener){  
42         listeners.addPropertyChangeListener(listener);  
43     }  
44       
45   
46     /** 
47      * 触发属性改变的事件 
48      */  
49     protected void firePropertyChange(String prop, Object oldValue, Object newValue) {  
50         listeners.firePropertyChange(prop, oldValue, newValue);  
51     }  
52     public static void main(String[] args) {  
53         DemoBeans beans = new DemoBeans();  
54         
55         beans.addPropertyChangeListener(
56                 new PropertyChangeListener(){  
57             public void propertyChange(PropertyChangeEvent evt) {  
58                  if(evt.getPropertyName().equals("demoVersion")){
59                      System.out.println("version_OldValue:"+evt.getOldValue());  
60                      System.out.println("version_NewValue:"+evt.getNewValue());  
61                      System.out.println("version_tPropertyName:"+evt.getPropertyName());
62                  }
63                  else
64                  {
65                      System.out.println("name_OldValue:"+evt.getOldValue());  
66                      System.out.println("name_NewValue:"+evt.getNewValue());  
67                      System.out.println("name_tPropertyName:"+evt.getPropertyName());
68                  }
69                   
70             }});  
71 
72         
73         beans.setDemoName("test");  
74         beans.setDemoVersion("v2000");
75       
76     }   
77 }