MethodType is a useful shape for describing a pattern, in reverse; the
“parameter” types are really the pattern bindings, and the “return” type is
really the (minimal) type of the target. With such a description, the
MethodType for a pattern is the right input to get the carrier for the pattern.
> On Mar 8, 2022, at 3:10 PM, Jim Laskey <jlas...@openjdk.java.net> wrote:
>
> On Tue, 8 Mar 2022 16:00:48 GMT, Maurizio Cimadamore
> <mcimadam...@openjdk.org> wrote:
>
>>> We propose to provide a runtime anonymous carrier class object generator;
>>> java.lang.runtime.Carrier. This generator class is designed to share
>>> anonymous classes when shapes are similar. For example, if several clients
>>> require objects containing two integer fields, then Carrier will ensure
>>> that each client generates carrier objects using the same underlying
>>> anonymous class.
>>>
>>> See JBS for details.
>>
>> src/java.base/share/classes/java/lang/runtime/Carrier.java line 852:
>>
>>> 850: * @throws IllegalArgumentException if number of component slots
>>> exceeds maximum
>>> 851: */
>>> 852: public static MethodHandle constructor(MethodType methodType) {
>>
>> What happens to the methodType return type? (both here and in the components
>> method). Should javadoc say anything?
>
> The return type is ignored. Going back to John's notion of just passing in
> the parameterTypes would work okay. I think when Brian wrote the original
> code he may have been thinking about keying on the MethodType (interned).
> I'll add a note about the return type.
>
> -------------
>
> PR: https://git.openjdk.java.net/jdk/pull/7744
