转载:http://wangyang0311.iteye.com/blog/368031
一般来说分为以下几步:
- 声明回调函数的统一接口interface A,包含方法callback();
- 在调用类caller内将该接口设置为私有成员private A XXX;
- 在caller内提供实现A接口的public方法(将外部该接口的实现类通过形参传入caller的XXX);
- caller的某个方法dosth()中会用到XXX.callback()方法;
- 在caller的实例中,先实现A接口,后调用dosth()方法;
网上流行代码:
//回调函数接口及方法
public interface ICallback {
public void func();
}
//回调函数接口实现类
public class ClassWithCallbackFunction implements ICallback{
public ClassWithCallbackFunction() {
}
public void func(){
System.out.println("cccccccccccccccccc");
}
}
public class Caller {
private ICallback callback; //私有接口成员
public void setCallback(ICallback callback) {
this.callback = callback; //接口成员的实现:从外部传入
}
public void doCallback() { //回调接口成员的方法
callback.func();
}
}
}
public class MainClass {
public MainClass() {
}
public static void main(String[] args) {
Caller caller = new Caller();
caller.setCallback(new ClassWithCallbackFunction() {
public void func() {
System.out.println("aaaaaaaaaa");
}
});
caller.doCallback(); //实现回调
}
}
//现实中是把doCallback()方法放在setCallback里调用,以上是为了说明回调原理
public class Caller {
ICallback callback;
public void doCallback() {
callback.func();
}
public void setCallback(ICallback callback) {
this.callback = callback;
doCallback();
}
}
java排序接口
interface Compare {
boolean lessThan(Object lhs, Object rhs);
boolean lessThanOrEqual(Object lhs, Object rhs);
} import java.util.*;
public class SortVector extends Vector {
private Compare compare; // 私有接口成员
public SortVector(Compare comp) {
compare = comp;
}
public void sort() {
quickSort(0, size() - 1);
}
private void quickSort(int left, int right) {
if(right > left) {
Object o1 = elementAt(right);
int i = left - 1;
int j = right;
while(true) {
while(compare.lessThan(
elementAt(++i), o1))
;
while(j > 0)
if(compare.lessThanOrEqual(
elementAt(--j), o1))
break;
if(i >= j) break;
swap(i, j);
}
swap(i , right);
quickSort(left, i-1);
quickSort(i+1, right);
}
}
private void swap(int loc1, int loc2) {
Object tmp = elementAt(loc1);
setElementAt(elementAt(loc2), loc1);
setElementAt(tmp, loc2);
}
}