CODEWITHSUNDEEP
javaoopcoding-style
Luke Vo
Luke Vo

Reputation: 20658

Advantage of using "this."

I've read many large projects in OOP, and I notice that a lot of them use this.[variable], [ClassName].[staticVariable]. For example:

public class ABC {

    private float mX;
    public static float y;    

    public float getX() {
        return this.mX;
    }

    public float doSomethingWithY() {
        return ABC.y;
    }

}

And even with Eclipse auto-generated Getters & Setters feature, it also comes with this.[variable], although it's unnecessary, because no local variable is declared there.

Is there any advantage when using these notations, or it's just a code style?

EDIT so some people don't misunderstand. I know what this and [ClassName].[staticVariable] stand for. But in this case, it's unnecessary. The question is: Even if it's unnecessary, why do guru coders still add it? When they need to update/fix a huge project, will there be any advantage and disadvantage?

Upvotes: 1

Views: 204

Answers (6)

saum22
saum22

Reputation: 882

Its syntax,if you want to access instance variable of a class use the (reference of the object).(instance variable name) .Like 

A a= new A();// for non static class,this for the current object
a.(instance variable name)
// for non static class do the same but use (class name).variable name

Upvotes: 0

Juan Antonio Gomez Moriano
Juan Antonio Gomez Moriano

Reputation: 13813

Basically with this, you KNOW for sure that you are working with a class attribute, not with a variable created inside the method or maybe received as a parameter.

And also, it helps in case you have a local var with the same name.

And the final reason: readability.

Upvotes: 3

subodh
subodh

Reputation: 6158

this.? '?' is a member variable, this is a reference to the current object.

see this

Upvotes: 0

Chip
Chip

Reputation: 3316

For small pieces of code it doesn't matter but sometimes this can happen:

public float getX() {
    ....
    int mX = someFunc()
    ...
    return mX;
}

In this case, the local value is returned instead of the member variable.

You normally want to be explicit and say this.mX. However, you shouldn't have huge functions anyway.

Upvotes: 0

mikera
mikera

Reputation: 106351

It's necessary in some circumstances, for example this. is required when you need to use a member variable rather than a local method parameter of the same name.

It's also necessary for static variables where you need to be specific which class you want to get the static variable from (many classes could define static variables with the same name).

Apart from the necessary cases, it's really a matter of coding style. My recommendation is to use it whenever it helps to resolve potential ambiguity.

Upvotes: 2

Oleksi
Oleksi

Reputation: 13097

In complicated methods, it's sometimes nice to make a distinction between instance variables in this class, and local variables in a particular function. This distinction is immediately obvious when you use "this."

Upvotes: 1

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