将变量传递给一个子类

Question

我是一个非程序员，有非常少的代码接触，但我想修改一个现有的代码库。我大大简化了下面的代码。请让我知道，如果我可以提供任何进一步的信息或如果这是没有意义的所有！Vocab很难。：）

public class ClassA {
    private String myVar = "hi";
    private String myStuff = "bye";
    private int myOption = 1;

    private String getMyClass(String myStuff) throws Exception {
        final MyClassChoice myClass = getMyClassChoice(myOption);
        return myClass.getResponse(myStuff);
    }

    private MyClassChoice getMyClassChoice(myOption) {
        switch(myOption) {
            case 1:
                return new ClassC();
            case 2:
                return new ClassD();    
        }
    }
}

public class ClassB {
    public abstract String getResponse(String myStuff) throws IOException;
}

public class ClassC extends ClassB {
    // do stuff with myStuff
    // do stuff with myVar
}

ClassD：

public class ClassD extends ClassB {
    // do stuff with myStuff
}

Answer 1

您可以在实例化对象时将其传递给构造函数并将其保存在实例变量中,

public class ClassA {
// ...
    private MyClassChoice getMyClassChoice(myOption) {
        switch(myOption) {
            case 1:
                return new ClassC(myVar);
            case 2:
                return new ClassD();    
        }
    }
}

public final class ClassC extends ClassB {

    private String myVar;

    // constructor:
    public ClassC(String myVar) {
        this.myVar = myVar;
    }

    // do stuff with myStuff
    // do stuff with myVar
    private void doStuff() {
        System.out.println(myVar);
    }
}

或者在使用该方法时将其传递给该方法,

public final class ClassA {
// ...
    public void someMethodUsingClassCDoStuff() {
        myClass.doStuff(myVar);
    }
}

public final class ClassC extends ClassB {

    // do stuff with myStuff
    // do stuff with myVar
    public void doStuff(String myVar) {
        System.out.println(myVar);
    }
}