Issue2752

classification

Title:	Allow Python functions to be used as a java.lang.FunctionalInterface
Type:	rfe	Severity:	normal
Components:		Versions:	Jython 2.7.3
		Milestone:

process

Status:	open	Resolution:
Dependencies:		Superseder:
Assigned To:		Nosy List:	jamesmudd
Priority:	normal	Keywords:

Created on 2019-03-27.20:14:11 by jamesmudd, last changed 2019-03-27.20:14:11 by jamesmudd.

Files
File name	Uploaded	Description	Edit	Remove
predicateExample.py	jamesmudd, 2019-03-27.20:14:11

Messages
msg12406 (view)	Author: James Mudd (jamesmudd)	Date: 2019-03-27.20:14:11
It would be nice in Java 8 onward if Python functions could be used where functional interfaces specified by lambdas (or method refs) can be used in Java. Examples would be in streams e.g. filtered_list = al.stream().filter(moreThanThree).collect(toList()) See attached example for full code. This fails at them moment because although Predicate is a @FunctionalInterface it also declares default methods. which results in it not being coerced in PyFunction.__tojava__(Class<?>) Probably for after 2.7.1 it might be easier to implement when default methods can be introspected via reflection.

msg12406 (view)

Author: James Mudd (jamesmudd)

Date: 2019-03-27.20:14:11

It would be nice in Java 8 onward if Python functions could be used where functional interfaces specified by lambdas (or method refs) can be used in Java.

Examples would be in streams e.g.

    filtered_list = al.stream().filter(moreThanThree).collect(toList())

See attached example for full code.

This fails at them moment because although Predicate is a @FunctionalInterface it also declares default methods. which results in it not being coerced in PyFunction.__tojava__(Class<?>)

Probably for after 2.7.1 it might be easier to implement when default methods can be introspected via reflection.

History
Date	User	Action	Args
2019-03-27 20:14:11	jamesmudd	create