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Java Java Data Structures - Retired Organizing Data Interfaces

Posted by Nicolas Hampton
Nicolas Hampton
44,638 Points

if (equals(other)) test

When you create the if gate inside the compareTo method, what are we comparing other to? What are we testing 'other' to in this test, and how does that work?

1 Answer

Craig Dennis
STAFF
Craig Dennis
Treehouse Teacher
Craig Dennis
Craig Dennis
Treehouse Teacher

equals is an inherited method from Object. It is comparing the current instance to the passed in Object.

You could also read that like this if it helps:

if (this.equals(other))  {
/// ...
}

Hope that helps!

Nicolas Hampton
Nicolas Hampton
44,638 Points

OK! So that could also be written as if (obj.equals(other)) {}, correct?

Craig Dennis
Craig Dennis
Treehouse Teacher
Craig Dennis
Craig Dennis
Treehouse Teacher

Not inside that method, because in that method obj is just the Object "version" of the parameter passed in, we then cast it to the BlogPost named other. It really is calling the inherited method that belongs to the instance.

Outside of that method, if you had an instance to any object you could call equals on it....just like we did with Strings.

"Hello".equals("Hello")