代理模式

自己可以去買東西，但也可以叫人家買，叫人家買就是一種代理

※自己類別

public interface Self {
    public void buyChair();
    public void buyTable();
}
--------------------
public class SelfImpl implements Self {
    private String buyMan = "自己";
    
    SelfImpl(String buyMan) {
        this.buyMan = buyMan;
    }
    
    @Override
    public void buyChair() {
        System.out.println(buyMan + "買椅子");
    }
    
    @Override
    public void buyTable() {
        System.out.println(buyMan + "買桌子");
    }
}

※

※代理類別

public class Proxy implements Self {
    private Self proxyMan;
    
    Proxy(Self proxyMan) {
        this.proxyMan = proxyMan;
    }
    
    @Override
    public void buyChair() {
        proxyMan.buyChair();
    }
    
    @Override
    public void buyTable() {
        proxyMan.buyTable();
    }
}

※

※測試

Self self = new SelfImpl("bruce");
self.buyChair();
self.buyTable();
System.out.println();
Self proxy = new Proxy(new SelfImpl("bruce"));
proxy.buyChair();
proxy.buyTable();

※前三行不用代理；後三行使用代理