What does it mean when the return type on a UML Diagram is an object?

Question

The class Chess has a method called knighMoves(int i, int j): Chess with Chess as the return type. Would the method header be

public static Chess knightMoves(int i, int j)
{
   return
}

What would the return statement entail?

Answer 1

Your model tells us that the operation knightMoves() is not static (static members should be underlined in the diagram), and it returns a Chess object.

You may be confused because the return type is also the enclosing class. But this does not change anything. The java method would look like:

public Chess knightMoves(int i, int j)
{
   Chess game;
   … // some code that would assign a value to game
       // and or change its state
   return game; 
}

or depending on your design intent:

public Chess knightMoves(int i, int j)
{
   … // some code that changes the current object
   return this; // return enclosing object
}