Java编程思想中关于闭包的一个例子

package InnerClass;

interface Incrementable {
void increment();
}

/** 被调1 */
// Very simple to just implement the interface
class Callee1 implements Incrementable {
private int i = 0;

@Override
public void increment() {
i++;
System.out.println("Callee1" + 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 implements Incrementable {
private int i = 0;

public void increment() {
super.increment();
i++;
System.out.println("Callee2：" + i);
}

private class Closure implements Incrementable {
public void increment() {
System.out.println("内部类实现接口");//1.这句是我加的。
Callee2.this.increment();//2.既然想表达与外部类的不同，此处为何还要调用外部类的方法实现同一个功能，造成迷惑
}
}

Incrementable getCallbackReference() {
return new Closure();
}
}

class Caller {
private Incrementable callbarckReference;

public Caller(Incrementable chb) {
callbarckReference = chb;
}

void go() {
callbarckReference.increment();
}
}

public class Callbacks {

public static void main(String[] args) {
Callee1 c1 = new Callee1();
Callee2 c2 = new Callee2();

MyIncrement.f(c2);
Caller caller1 = new Caller(c1);
Caller caller2 = new Caller(c2.getCallbackReference());
caller1.go();
caller1.go();
caller2.go();
caller2.go();
}
}