Implementing two interface methods with same signature

[jjoensuu]

Dear ladies and gents...

I have a newbie question about Java interfaces. I have not implemented any interfaces yet, so I do not know if what I am describing here could ever happen in "real life"...

Let's say I create a class that implements two interfaces that both have a method with the same signature. Furthermore, even though the methods have the same signature, they are supposed to carry out different functions. As a rather lousy hypothetical example:


interface VacationSpots {
//return true if location is a resort
boolean resort();
}

interface SortRooms {
//return true once rooms are sorted
boolean resort();
}

public class Resort implements VacationSpots, SortRooms {
//other code
boolean isResort;
//other code (constructor etc)
public boolean resort(){
return isResort;
}
//other code
}

QUESTION: In this sort of a case, which "resort" method is actually implemented?

TIA

JJ

 

[Diancecht]

In a class, you can just implement one method for each signature.

In that case, an unique method will apply for both cases.

Cheers,
Dian

 

[sedj]

The class defines the method, not the interface - so while the syntax/scenario is a bit odd, it is valid.

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[timw]

Just remember that, conceptually, the interface is specifying a 'contract'(i.e assumed behaviour) between the classes which implement it, and the classes which use instances of it.

If you have a class which implements two interfaces, both of which specifiy the same method, then that method would have to satisfy two possibly distinct contracts. Any consumer class using your method with respect to one interface (i.e one contract) would get behaviour put in place to satisfy the second contract too. This would probably be a bad side-effect.

Tim
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