Java：方法签名

Question

I want to make an interface Mergeable that declares a method merge() . A class that implements this will have to implement the method like follows:

SomeObject.java

public class SomeObject implements Mergeable

    @Override
    public SomeObject merge(SomeObject other) {...}

See that the return and parameter type are set to the implementing class. Is there a way to enforce this and how would I set the method signature in the interface?

Answer 1

Look at the Comparable interface for an example. You'll probably have to write something like

interface Mergeable<T> {
   T merge(T other);
}

...and then anytime you want to accept something Mergeable , write

<T extends Mergeable<T>> void somethingWithMergeables(T merge1) {
   ...
}