命令行模式 示例

UML

代码示例

创建一个接口

public abstract class KaiDanHandler {

    /**
     * 持有后继的责任对象
     */
    protected KaiDanHandler successor;



    /**
     * 传入参数的，根据具体需要来选择是否传递参数
     */
    public abstract void handleRequest(Data data);
}

创建实现接口的实现类

public class JiNengHandler extends KaiDanHandler {
    
    @Override
    public void handleRequest(Data data) {
        if (data.showJiNeng){
            System.out.println("请去选择节能补贴的赠品");
        }else {
            if (null != successor){
                successor.handleRequest(data);
            }else {
                System.out.println("现在正式开单");
            }

        }
    }
}

public class YanbaoHandler extends KaiDanHandler {
    
    @Override
    public void handleRequest(Data data) {
        if (data.showYanbao){
            System.out.println("请去购买延保");
        }else {
            if (null != successor){
                successor.handleRequest(data);
            }else {
                System.out.println("现在正式开单");
            }
        }
    }
}

public class ZaiTuHandler extends KaiDanHandler {

    @Override
    public void handleRequest(Data data) {

        if (data.showZaitu){
            System.out.println("是否要取消所选在途的商品");
        }else {
            if (null != successor){
                successor.handleRequest(data);
            }else {
                System.out.println("现在正式开单");
            }
        }
    }
}

创建参数实体

public class Data {

    public boolean showZaitu;
    public boolean showYanbao;
    public boolean showJiNeng;
}

模拟请求的客户端

public class Client {

    private Data mData;

    public static void main(String[] args) {
        Client client = new Client();
        client.mData  = client.mockData();

        //创建实现者对象
        YanbaoHandler yanbaoHandler = new YanbaoHandler();
        ZaiTuHandler zaiTuHandler = new ZaiTuHandler();
        JiNengHandler jiNengHandler = new JiNengHandler();

        //设置实现功能的下一任对象
        yanbaoHandler.successor = zaiTuHandler;
        zaiTuHandler.successor = jiNengHandler;

        //发出命令请求
        yanbaoHandler.handleRequest(client.mData);
    }
    private Data mockData(){
        Data data = new Data();
        data.showYanbao = true;
        data.showZaitu = false;
        data.showJiNeng = true;
        return data;
    }
}