// innerclasses/Callbacks.java // Using inner classes for callbacks

雨点打透心脏的1/2处 2022-07-15 08:58 150阅读 0赞

// innerclasses/Callbacks.java  
// Using inner classes for callbacks  
package innerclasses;  
interface Incrementable\{   
    void increment();    
\}

// Very simple to just implement the interface   
class Callee1 implements Incrementable \{   
 private int i = 0;    
 public void increment() \{   
    i++;   
    System.out.println(i);    
  \}   
\}  
    
   
class  MyIncrement \{   
 public void increment() \{System.out.println("Other operation");\}    
 static void f(MyIncrement mi) \{mi.increment();\}   
\}   
   
// If your class must implement increment() in   
// some other way, you must use an inner class:    
class Callee2 extends MyIncrement \{   
 private int i=0;   
 public void increment() \{   
  super.increment();     
  i++;      
  System.out.println(i);      
 \}   
   
 private class Closure implements Incrementable \{    
  public void increment() \{   
    // Specify outer-class method, otherwise   
    // you'd get an infinite recursion   
   Callee2.this.increment();   
   \}   
 \}   
   
 Incrementable getCallbackReference() \{   
     return new Closure();    
 \}   
   
 \}    
   
class Caller \{   
 private Incrementable callbackReference;   
 Caller(Incrementable cbh) \{callbackReference = cbh;\}   
 void go() \{callbackReference.increment();\}   
\}  
   
    
   
public class Callbacks \{   
 public static void main(String\[\] args) \{    
   Callee1 c1 = new Callee1();      
   Callee2 c2 = new Callee2();     
   MyIncrement.f(c2);   
                     //Other operation  
         //1  
   Caller caller1 = new Caller(c1);     
   Caller caller2 = new Caller(c2.getCallbackReference());   
   caller1.go();  
                    //1  
   caller1.go();    //2  
    
   caller2.go();   //Other operation   
                   //2

caller2.go();  //Other operation  
                  //3  
  \}   
\}