hg: lambda/lambda/langtools: Handle non-static method references from static context. More specifically, if f is an instance method of Z whose signature is A, B->C, then #obj.f is of type A, B->C and #Z.f is of type Z, A, B->C.

[Rémi Forax]

Le 04/08/2010 16:54, Maurizio Cimadamore a écrit :
> On 04/08/10 15:36, Kevin Bourrillion wrote:
>    
>> Hello,
>>
>> Does this mean that we could replace
>>
>>    Predicate<Employee>  p = { e ->  e.isPartTime() };
>>
>> with
>>
>>    Predicate<Employee>  p = #Employee.isPartTime;
>>
>> ?  If so, very cool.
>>      
> Yes, the two are the same :-)
>
> Maurizio
>    

And the coolest thing is that #Employee.isPartTime is just a LDC.

Predicate<Employee>  p = #Employee.isPartTime;

will be compiled to

ldc #Employee.isPartTime
ldc Predicate.class
invokestatic MethodHandles.asSam 
(Ljava/lang/MethodHandle;Ljava/lang/Class;)LObject;
checkcast LPredicate;

knowing that asSam() should always return an instance of the same class 
for the same SAM.

Rémi

>>
>>
>>
>> On Wed, Aug 4, 2010 at 7:13 AM,<maurizio.cimadamore at oracle.com
>> <mailto:maurizio.cimadamore at oracle.com>>  wrote:
>>
>>      Changeset: 443eb1d3b96c
>>      Author:    mcimadamore
>>      Date:      2010-08-04 15:10 +0100
>>      URL:
>>      http://hg.openjdk.java.net/lambda/lambda/langtools/rev/443eb1d3b96c
>>
>>      Handle non-static method references from static context. More
>>      specifically, if f is an instance method of Z whose signature is
>>      A,B->C, then #obj.f is of type A,B->C and #Z.f is of type Z,A,B->C.
>>
>>      ! src/share/classes/com/sun/tools/javac/comp/Attr.java
>>      ! src/share/classes/com/sun/tools/javac/parser/JavacParser.java
>>      ! test/tools/javac/lambda/MethodReference05.java
>>      - test/tools/javac/lambda/MethodReference05.out
>>      + test/tools/javac/lambda/MethodReference07.java
>>      + test/tools/javac/lambda/MethodReference08.java
>>      + test/tools/javac/lambda/MethodReference08.out
>>      + test/tools/javac/lambda/MethodReference09.java
>>      + test/tools/javac/lambda/MethodReference09.out
>>
>>
>>
>>
>>
>> -- 
>> Kevin Bourrillion @ Google
>> http://guava-libraries.googlecode.com
>>
>>      
>
>