java - 面向对象 : new class implementing requires additional parameter

Question

假设我有一个如下所示的界面

public interface ConditionChecker {
    boolean isInCondition(Person p);
}

我想创建一个实现上述接口(interface)的新类，但我需要用另一个参数实现一个函数

public class MacroConditionChecker implements ConditionChecker {
    public boolean isInCondition(Person p, MacroView mv);
}

两个问题:
一:如果我将接口(interface)签名更改为 boolean isInCondition(Person p, MacroView mv);，那么我需要更新所有实现 ConditionChecker 的类
二:我希望 ConditionChecker 的消费者按原样调用 isInCondition

我认为这意味着:

public class MacroConditionChecker implements ConditionChecker {
    private static final MacroView mv;
    public MacroConditionChecker(MacroView mv) {
        this.mv = mv;
    }
    public boolean isInCondition(Person p){
        // now i have access to MacroView
    }
}

所以，我唯一需要做的更改是在我决定使用 MacroConditionChecker 时进行更改，并且对 isInCondition 的调用没有更改

我在正确的轨道上吗？还是有其他方法可以做到这一点？

或者我应该将 MacroView 分离出来作为它自己的界面

public class MacroConditionChecker implements ConditionChecker implements MacroView

Answer 1

ConditionChecker 提醒Command design pattern .来自链接页面的评论:

Command decouples the object that invokes the operation from the one that knows how to perform it. To achieve this separation, the designer creates an abstract base class that maps a receiver (an object) with an action (a pointer to a member function). The base class contains an execute() method that simply calls the action on the receiver.

这正是您所需要的。如果您只需要检查 Person 对象的内部状态就足够了。当您想使用外部 API 检查 Person 对象时，可以创建在构造函数中将外部 API 与 Person 绑定(bind)的实现> 方法中的对象。简单示例:

import java.util.ArrayList;
import java.util.List;

public class DesignPatterns {

    public static void main(String[] args) {
        List<ConditionChecker> checkers = new ArrayList<>();
        checkers.add(person -> person != null);
        checkers.add(person -> person.getName() != null);
        checkers.add(person -> person.getName().length() > 0);
        checkers.add(new MacroViewConditionChecker(new MacroView()));
        checkers.add(new RestApiConditionChecker(new RestApi()));

        Person person = new Person();
        person.setName("Name");

        for (ConditionChecker checker : checkers) {
            System.out.println(checker.isInCondition(person));
        }
    }
}

interface ConditionChecker {

    boolean isInCondition(Person person);
}

class MacroViewConditionChecker implements ConditionChecker {

    private final MacroView macroView;

    public MacroViewConditionChecker(MacroView macroView) {
        this.macroView = macroView;
    }

    @Override
    public boolean isInCondition(Person person) {
        return macroView != null;
    }
}

class MacroView {
}

class RestApiConditionChecker implements ConditionChecker {

    private final RestApi restApi;

    public RestApiConditionChecker(RestApi restApi) {
        this.restApi = restApi;
    }

    @Override
    public boolean isInCondition(Person person) {
        return restApi.checkName(person.getName());
    }
}

class RestApi {

    public boolean checkName(String name) {
        System.out.println("Validate name ...");
        System.out.println(name + " is valid");

        return true;
    }
}

class Person {

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

您可以将此模式与 Chain of Responsibility 一起使用.此方法不会将 Person 对象与任何实现绑定(bind)。此绑定(bind)在特定的 ConditionChecker 实现中完成，可以轻松交换。