（引用网上例子）假设有一个Italk接口，有空的方法talk()(说话)，所有的OnlyTalk对象都实现(implements)这个接口，实现talk()方法，前端有很多地方都将OnlyTalk实例化，执行talk方法，后来发现这些前端里有一些除了要说话以外还要唱歌(sing)，那么我们既不能在Italk接口里增加sing()方法，又不能在每个前端都增加sing方法，我们只有增加一个代理类TalkSing，这个代理类里实现talk和sing方法，然后在需要sing方法的客户端调用代理类即可，代码如下:

 1  interface Italk
 2 {
 3
 4     public void talk(String st);
 5 }
 6
 7  //Italk实现类
 8  class OnlyTalk implements Italk
 9  {
10      public String name;
11      public int age;
12     public String getName() {
13         return name;
14     }
15     public void setName(String name) {
16         this.name = name;
17     }
18     public int getAge() {
19         return age;
20     }
21     public void setAge(int age) {
22         this.age = age;
23     }
24     public OnlyTalk(String name,int age)
25     {
26         this.name=name;
27         this.age = age;
28     }
29
30     public void talk(String s) {
31         // TODO Auto-generated method stub
32         System.out.println(s+":  我的名字是："+name+"，我的年龄是："+age);
33     }
34
35
36  }
37
38  //聊天&唱歌，代理类
39  class TalkSing implements Italk
40  {
41      OnlyTalk talker;
42      public String song;
43      public TalkSing(OnlyTalk talker)
44      {
45          this.talker=talker;
46      }
47      public void talk(String ss)
48      {
49          talker.talk(ss);
50      }
51      public void talk(String ss,String song)
52      {
53          talker.talk(ss);
54          sing(song);
55      }
56      private void sing(String song)
57      {
58          System.out.println("我唱的是"+song+"歌");
59      }
60  }
61  //应用端
62 public class SingTalk {
63
64     public static void main(String[] args) {
65         // TODO Auto-generated method stub
66
67         OnlyTalk people = new OnlyTalk("华为",20);
68         people.talk("没有代理");
69         System.out.println();
70         TalkSing peopleplus = new TalkSing(people);
71         peopleplus.talk("添加代理", "好运来");
72     }
73
74 }

//Pattern构造器：
private Pattern(String p, int f) {pattern = p;flags = f;// Reset group index countcapturingGroupCount = 1;localCount = 0;if (pattern.length() > 0) {compile();} else {root = new Start(lastAccept);matchRoot = lastAccept;}}

方法一：
public static Pattern compile(String regex) {return new Pattern(regex, 0);}
方法二：public static Pattern compile(String regex, int flags) {return new Pattern(regex, flags);}