第七章-复用类-代理

练习11：（3）修改 Detergent.java,让它使用代理。

一：我的答案：

package com.learnJava.test;

/**
 * @Author zhuchangli
 * @Date 2019/9/15
 **/
public class DetergentDelegation {

    private Cleanser cleanser = new Cleanser();
    private String s = "Cleanser ";
    public void scrub(){
        cleanser.append(" Detergent.scrub()");
        cleanser.scrub();
    }

    public void append(String a){
        cleanser.append(a);
    }

    public void dilute(){
        cleanser.dilute();
    }

    public void apply(){
        cleanser.applay();
    }

    public void foam(){
        append("foam()");
    }

    public String toString(){
        return cleanser.toString();
    }

   public static void main(String [] args){
        DetergentDelegation d = new DetergentDelegation();
        d.dilute();
        d.apply();
        d.scrub();
        d.foam();
        System.out.println(d);
        System.out.println("Testing base class");
        Cleanser.main(args);

   }
}

运行结果：

Cleanserdilute()applay() Detergent.scrub()scrub()foam()
Testing base class
Cleanserdilute()applay()scrub()

使用继承时：

package com.learnJava.test;

/**
 * @Author zhuchangli
 * @Date 2019/9/14
 **/
class Cleanser{
    private String s = "Cleanser";
    public void append(String a) { s += a; }
    public void dilute(){ append("dilute()"); }
    public void applay(){append("applay()");}
    public void scrub(){append("scrub()");}
    public String toString(){return s;}

    public static void main(String [] args){
        Cleanser x = new Cleanser();
        x.dilute();
        x.applay();
        x.scrub();
        System.out.println(x);
    }
}
//洗涤剂
public class Detergent extends Cleanser{
    public void scrub(){
        append("Detergent.scrub()");
        super.scrub();
    }

    // foam 泡沫
    public void foam(){ append("foam()");}

    public static void main(String [] args){
        Detergent x = new Detergent();
        x.dilute();
        x.applay();
        x.scrub();
        x.foam();
        System.out.println(x);
        System.out.println("Testing base class");
        Cleanser.main(args);
    }
}

运行结果：

Cleanserdilute()applay()Detergent.scrub()scrub()foam()
Testing base class
Cleanserdilute()applay()scrub()

二：参考答案

package com.learnJava.test;

/**
 * @Author zhuchangli
 * @Date 2019/9/15
 **/

class Cleanser11{
    private String s = "Cleanser11";
    public void append(String a) { s += a;}
    public void dilute() {append(" dilute()");}
    public void apply() {append(" apply()");}
    public void scrub() {append(" scrub()");}
    public String toString() {return s;}

    public static void main(String [] args){
        Cleanser11 x = new Cleanser11();
        x.dilute();
        x.apply();
        x.scrub();
        System.out.println(x);
    }
}

public class DetergentDelegation11 {

    private String s = "DetergentDelegation11 ";
    private Cleanser11 c11 = new Cleanser11();

    public void append(String a){
        s += a;
    }

    public void dilute(){
        c11.dilute();
    }

    public void apply() {c11.apply();}

    public void scrub() {
        append("DetergentDelegation11");
        c11.scrub();
    }

    public void foam(){
        append(" foam()");
    }

    public String toString(){
        return s + " " + c11;
    }

    public static void main(String [] args){
        DetergentDelegation11 d = new DetergentDelegation11();
        d.dilute();
        d.apply();
        d.scrub();
        d.foam();
        System.out.println(d);
        System.out.println("Testing base class");
        Cleanser11.main(args);
    }


}

运行结果：

DetergentDelegation11 DetergentDelegation11 foam() Cleanser11 dilute() apply() scrub()
Testing base class
Cleanser11 dilute() apply() scrub()

总结：

代理是什么：

将一个成员置于所要构造的类中，在新类中暴露了该成员对象的所有方法。

只提供在成员对象的方法的某个子集。