CODEWITHSUNDEEP
javalaw-of-demeter
JaJaJaJapan
JaJaJaJapan

Reputation: 37

Demeter Law - Calling a method of a class inside another method of a different class

If I have a class C containing a method f that takes as argument an object of type D (another class I defined)

If I call the methods of the object D inside of the method f, will I be violating the law of Demeter? and why?

Ex:

public C {
    public void f(D object) {
        int x = object.sumOfNumbers(2,3);
    }
}

Upvotes: 1

Views: 261

Answers (1)

gil.fernandes
gil.fernandes

Reputation: 14621

This call does not violate Demeter's law. To violate it you will need to do this:

In this case, an object A can request a service (call a method) of an object instance B, but object A should not "reach through" object B to access yet another object, C, to request its services

Source: Wikipedia

You are not reaching object C in your code.

Using the class names (A, B, C) used in Wikipedia, your question code should look like this:

public class A {
    public void f(B object) {
        int x = object.sumOfNumbers(2,3);
    }
}

There is here no C class you are accessing.

And here is a violation of this law:

public class A {
    public void f(B object) {
        C myC = object.getC();
        int x = myC.sumOfNumbers(2,3);
    }
}

Upvotes: 2

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