装饰者模式

一、煎饼案例

public class Battercake {

    protected String getMsg(){
        return "煎饼";
    }

    public int getPrice(){
        return 5;
    }

}

public class BattercakeWithEgg extends Battercake{
    @Override
    protected String getMsg() {
        return super.getMsg() + "+1个鸡蛋";
    }

    @Override
    //加一个鸡蛋加1块钱
    public int getPrice() {
        return super.getPrice() + 1;
    }
}

public class BattercakeWithEggAndSausage extends BattercakeWithEgg{
    @Override
    protected String getMsg() {
        return super.getMsg() + "+1根香肠";
    }

    @Override
    //加一个香肠加2块钱
    public int getPrice() {
        return super.getPrice() + 2;
    }
}

 test

public class BattercakeTest {
    public static void main(String[] args) {

        Battercake battercake = new Battercake();
        System.out.println(battercake.getMsg() + ",总价格：" + battercake.getPrice());

        Battercake battercakeWithEgg = new BattercakeWithEgg();
        System.out.println(battercakeWithEgg.getMsg() + ",总价格：" + battercakeWithEgg.getPrice());

        Battercake battercakeWithEggAndSausage = new BattercakeWithEggAndSausage();
        System.out.println(battercakeWithEggAndSausage.getMsg() + ",总价格：" + battercakeWithEggAndSausage.getPrice());

    }

}

 二、改进

　　

public class BaseBattercake extends Battercake {
    protected String getMsg(){
        return "煎饼";
    }

    public int getPrice(){
        return 5;
    }
}

public abstract class Battercake {
    protected abstract String getMsg();
    protected abstract int getPrice();
}

public abstract class BattercakeDecorator extends Battercake {

    //静态代理，委派
    private Battercake battercake;

    public BattercakeDecorator(Battercake battercake) {
        this.battercake = battercake;
    }

    protected abstract void doSomething();

    @Override
    protected String getMsg() {
        return this.battercake.getMsg();
    }

    @Override
    protected int getPrice() {
        return this.battercake.getPrice();
    }
}

public class EggDecorator extends BattercakeDecorator {
    public EggDecorator(Battercake battercake) {
        super(battercake);
    }

    protected void doSomething() {

    }

    @Override
    protected String getMsg() {
        return super.getMsg() + "+1个鸡蛋";
    }

    @Override
    protected int getPrice() {
        return super.getPrice() + 1;
    }
}

public class SausageDecorator extends BattercakeDecorator {
    public SausageDecorator(Battercake battercake) {
        super(battercake);
    }

    protected void doSomething() {

    }

    @Override
    protected String getMsg() {
        return super.getMsg() + "+1根香肠";
    }

    @Override
    protected int getPrice() {
        return super.getPrice() + 2;
    }
}

public class BattercakeTest {
    public static void main(String[] args) {

        Battercake battercake;
        //路边摊买一个煎饼
        battercake = new BaseBattercake();
        //煎饼有点小，想再加一个鸡蛋
        battercake = new EggDecorator(battercake);
        //再加一个鸡蛋
//        battercake = new EggDecorator(battercake);
        //很饿，再加根香肠
        battercake = new SausageDecorator(battercake);
        battercake = new SausageDecorator(battercake);
        battercake = new SausageDecorator(battercake);
        battercake = new SausageDecorator(battercake);
        battercake = new SausageDecorator(battercake);


        //跟静态代理最大区别就是职责不同
        //静态代理不一定要满足is-a的关系
        //静态代理会做功能增强，同一个职责变得不一样

        //装饰器更多考虑是扩展

        System.out.println(battercake.getMsg() + ",总价：" + battercake.getPrice());


    }

}

 三、登陆案例

public interface ISigninService {
    ResultMsg regist(String username, String password);


    /**
     * 登录的方法
     * @param username
     * @param password
     * @return
     */
    ResultMsg login(String username, String password);
}

public class Member {

    private String username;
    private String password;
    private String mid;
    private String info;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getMid() {
        return mid;
    }

    public void setMid(String mid) {
        this.mid = mid;
    }

    public String getInfo() {
        return info;
    }

    public void setInfo(String info) {
        this.info = info;
    }
}

public class ResultMsg {

    private int code;
    private String msg;
    private Object data;

    public ResultMsg(int code, String msg, Object data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
}

public class SigninService implements ISigninService {

    public ResultMsg regist(String username,String password){
        return  new ResultMsg(200,"注册成功",new Member());
    }

    /**
     * 登录的方法
     * @param username
     * @param password
     * @return
     */
    public ResultMsg login(String username,String password){
        return null;
    }
}

 改进

　　

public interface ISiginForThirdService extends ISigninService {

    /**
     * QQ登录
     * @param id
     * @return
     */
    ResultMsg loginForQQ(String id);

    /**
     * 微信登录
     * @param id
     * @return
     */
    ResultMsg loginForWechat(String id);

    /**
     * 记住登录状态后自动登录
     * @param token
     * @return
     */
    ResultMsg loginForToken(String token);

    /**
     * 手机号登录
     * @param telphone
     * @param code
     * @return
     */
    ResultMsg loginForTelphone(String telphone, String code);

    /**
     * 注册后自动登录
     * @param username
     * @param passport
     * @return
     */
    ResultMsg loginForRegist(String username, String passport);
}

public class SiginForThirdService implements ISiginForThirdService {

    private ISigninService signinService;

    public SiginForThirdService(ISigninService signinService) {
        this.signinService = signinService;
    }

    public ResultMsg regist(String username, String password) {
        return signinService.regist(username,password);
    }

    public ResultMsg login(String username, String password) {
        return signinService.login(username,password);
    }

    public ResultMsg loginForQQ(String id) {
        return null;
    }

    public ResultMsg loginForWechat(String id) {
        return null;
    }

    public ResultMsg loginForToken(String token) {
        return null;
    }

    public ResultMsg loginForTelphone(String telphone, String code) {
        return null;
    }

    public ResultMsg loginForRegist(String username, String passport) {
        return null;
    }
}

 test

public class DecoratorTest {

    public static void main(String[] args) {

        //满足一个is-a
        ISiginForThirdService siginForThirdService = new SiginForThirdService(new SigninService());
        siginForThirdService.loginForQQ("sdfasfdasfsf");

    }


}