[
https://issues.apache.org/jira/browse/JDO-652?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14902690#comment-14902690
]
Tilmann Zäschke commented on JDO-652:
-------------------------------------
In https://issues.apache.org/jira/browse/JDO-749, ANdy wore in response to my
question about streams/lambdas in queries:
??And about yet another 'redesign' of the query API, we have waited nearly 3
years for this one from the provision of the DN TypesafeQuery API with little
input from others. Bear in mind that I wouldn't be contributing much time, so
if you want it then you need to provide time/ideas/implementations/tests.??
Sorry, I only really joined the discussions here a few months ago, I don't know
the history, but I certainly don't want to be disruptive.
I thought about streams/lambdas a bit more, and I think one key issue is that
the API will look very different from JDOQL or the proposed typesafe API, it
simply will have to look like the Java 8 stream API ({{filter()}},
{{reduce()}}, {{sort()}}, {{forEach()}}, ...).
Also, it will require considerable effort to even verify feasibility, I guess
at least another 6 months at least. The result may be that it actually doesn't
really work or makes sense.
I don't know what the JDO 3.2 timeline is, but I suspect it may be best to
follow through with the current proposal.
I suppose the disadvantage of duplicating the query at a later point with a
stream API is smaller than waiting for an API that may not even work. I guess
it boils down to the argument that having a 'very good' solution now is
preferable to potentially 'perfect' solution that may never come.
> Provision of a typesafe refactor-friendly query capability for JDOQL
> --------------------------------------------------------------------
>
> Key: JDO-652
> URL: https://issues.apache.org/jira/browse/JDO-652
> Project: JDO
> Issue Type: New Feature
> Components: api, specification, tck
> Reporter: Andy Jefferson
> Fix For: JDO 3.2
>
> Attachments: typesafe.patch, typesafe_manifest.patch
>
>
> There are various querying capabilities of this type around. JPA2 has its
> Criteria query API. Third party solutions like QueryDSL also exist, in its
> case providing a JDOQL implementation (as well as JPQL, and HQL). We should
> seriously consider introducing something along these lines in the JDO2.4
> timeframe.
> There is a comparison of JPA Criteria with QueryDSL over at
> http://source.mysema.com/forum/mvnforum/viewthread_thread,49
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
