如何重构两个非常相似的方法 [英] How refactor two methods which are very similar

问题描述

我有以下课程:

public interface IBaseInterface {
    String baseMethod();
}

public class BaseClass implements IBaseInterface{

    @Override
    public String baseMethod() {
        return "baseInterface";
    }

    public String otherBaseMethod(){
        return "otherBaseMethod";
    }

}

public class ClassA implements IBaseInterface{

    @Override
    public String baseMethod() {
        return "ClassA";
    }

    public String getAttribiuteA(){
        return "A";
    }

}

public class ClassB implements IBaseInterface {

    @Override
    public String baseMethod() {
        return "ClassB";
    }

    public String getAttribiuteB(){
        return "B";
    }

}

现在我有两个非常相似的方法:

And now I have two very similar methods:

private String getBaseMethod(){

    /** Do something */

    if(/**    */){
        BaseClass base = new BaseClass();
        return base.baseMethod();
    }else if (/**    */){
        ClassA a = new ClassA();
        return a.baseMethod();
    } else {
        ClassB b = new ClassB();
        return b.baseMethod();
    }
}

private String getOtherMethod(){

    /** Do something */

    if(/**    */){
        BaseClass base = new BaseClass();
        if(/**    */){
            return base.baseMethod();
        } else{
            return base.otherBaseMethod()
        }
    } else if(/**    */){
        ClassA a = new ClassA();
        return a.getAttribiuteA()
    } else{
        ClassB b = new ClassB();
        return b.getAttribiuteB();
    }
}

这两种方法非常相似.在 if 子句中是相同的条件.我们可以把这两种方法做得更好吗?更抽象"?

These two methods are very similar. In if-Clause are the same conditions. Can we make these two methods better? More "abstractly" ?

我不能在我的类中做任何改变，只能在方法中.

I can not make any changes in my classes, only in methods.

推荐答案

我假设这里要求的是使用多态"

I assume what is being asked here is to use 'Polymorphism'

因为BaseClass、ClassA和ClassB这三个类都实现了interfcae IBaseInterface，所以你可以像下面的例子那样做:

Because all three classes, BaseClass, ClassA, and ClassB, all implement interfcae IBaseInterface, so you can do such thing like following example:

 IBaseInterface i1 = new BaseClass();
 IBaseInterface i2 = new ClassA();
 IbaseInterface i3 = new ClassB();

正如您此时已经注意到的，您也可以使用 List 来保存您的类.

And as you already noticed at this point, you may use List to save your classes too.

 List<IBaseInterface> interfaces = new ArrayList<>();
 interfaces.add(i1);
 ....

等等

因为 IBaseInterface 有方法 baseMethod()，现在您可以简单地遍历列表并为每个 IBaseInterface 对象调用 baseMethod() 方法.

Because IBaseInterface has method baseMethod(), now you can simply iterate through the list and invoke baseMethod() method for each IBaseInterface objects.

看看多态行为"

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