apply

[Doug Lea]

On 12/16/12 17:30, Remi Forax wrote:

>> Could someone please explain clearly and compellingly why we are using
>> different method names for all the functional forms in java.util.function
>> instead of just "apply"?
>
> Problems come when a functional interface inherits from another, because in that
> case the two methods are considered as overloads and Java has specific rules for
> overloads like a method with the same parameters can't have different return type.
> by example, if Supplier use apply, IntSupplier can not inherits from Supplier.
>
> interface Supplier<T> { T apply(); }
> interface IntSupplier extends Supplier { int apply(); }   // won't compile

> and we want InSupplier to inherit from Supplier to avoid function interface to
> functional interface conversion that currently always creates a new object.

So instead live with a form that always forces you to remember
to use the specially named method in the case of known-to-be-primitives?

>
>> Does anyone think that other users won't find this very annoying?
>
> It's annoying for framework writers not users of those frameworks because
> writing a lambda doesn't require to know the method name.
>

Where I guess "Framework writers" must mean:
1. anyone using higher-order functions
2. anyone needing to remember to for example use "operateAsDouble"
vs the "operate" version in DoubleBinaryOperator to ensure lack of boxing.



-Doug