Bug 474001

Summary:	Consider Java 8 impact on Handly API design
Product:	[Technology] Handly	Reporter:	Vladimir Piskarev <pisv>
Component:	Core	Assignee:	Vladimir Piskarev <pisv>
Status:	RESOLVED FIXED	QA Contact:
Severity:	enhancement
Priority:	P3	Keywords:	api
Version:	0.4
Target Milestone:	0.4
Hardware:	All
OS:	All
Whiteboard:
Bug Depends on:
Bug Blocks:	472914, 474023

Description Vladimir Piskarev

2015-07-31 05:35:10 EDT

Handly is a relatively new project and Java 8 is coming into mainstream. We can't afford to finalize Handly core APIs without giving careful consideration to potential impact of the new Java 8 features such as default interface methods and streams.

Comment 1 Vladimir Piskarev

2015-07-31 07:37:58 EDT

It is important to note that streams don't mix well with checked exceptions. See for example http://stackoverflow.com/questions/19757300/java-8-lambda-streams-filter-by-method-with-exception

Since many Eclipse Platform APIs throw CoreException, this might become quite an issue for stream-oriented processing. This general problem calls for a general solution. I don't (yet) think we can and should address it separately in Handly.

Comment 2 Vladimir Piskarev

2015-07-31 09:22:20 EDT

Default interface methods would help with evolution of interfaces that clients may implement and could provide convenient "mini-implementations" that don't lock clients into a particular class hierarchy (see bug 474023 for an example of where they would be really useful in Handly).

Comment 3 Vladimir Piskarev

2015-07-31 10:35:25 EDT

Just a note that streams also don't mix especially well with iterables:

http://stackoverflow.com/questions/23114015/why-does-iterablet-not-provide-stream-and-parallelstream-methods

Comment 4 Vladimir Piskarev

2015-07-31 10:41:41 EDT

A broad perspective on API design with Java 8:

https://jarthorn.github.io/EclipseCon2014/java8/

Comment 5 Vladimir Piskarev

2015-08-07 06:16:00 EDT

To summarize, I think that default methods in Java 8 could be really useful for Handly. Streams look promising, but unfortunately don't mix well with checked exceptions such as the CoreException omnipresent in Eclipse. We need to adopt Java 8 as soon as it becomes feasible (bug 474391).