Standard interface for no argument function

Question

Is there in Java 6 (or any compatible library) standard interface for no argument function and generic return type.

Something like:

interface Foo<T> {
      T call();
}

Answer 1

It's a Supplier<T> - it takes nothing, and supplies with T. And the abstract method it defines is nice to be called get()

interface Supplier<T> {
   T get();
}

Note that in Java8, this (@FunctionalInterface) already exists (it's called Supplier), so if you run your code under Java8, there's no need to define a custom interface.

Also, if you run your code under some pre-Java8 version, then you can use the Guava's Supplier interface.