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https://issues.apache.org/jira/browse/JDO-652?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16608775#comment-16608775
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Andy Jefferson commented on JDO-652:
------------------------------------
And how is the Java API to know about "Number" when you define the type as
"Double"? The "IfElseExpression" represents the type that it returns. You
passed "Double" to the builder method, not "Number".
Why would the builder method take 3 arguments? An "If-Else" can have multiple
"if"s and one "else". Specifying the "if-then" clauses individually makes it
more fluent IMHO.
I can't see how "IfThenElse" can extend DoubleExpression ... because the type
is "IfThenElse<T>" ... i.e dependent on the type that it returns. And if the
"If-Else" is returning a String? or a Date? IfElseNumeric, IfElseString and so
on? (which makes it way less extensible).
Why not provide some code that demonstrates how that will work (and preferably
an implementation, to go in
[https://github.com/datanucleus/datanucleus-api-jdo/blob/master/src/main/java/org/datanucleus/api/jdo/query/IfElseExpressionImpl.java]
)
> 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
> Assignee: Michael Bouschen
> Priority: Major
> Fix For: JDO 3.2
>
> Attachments: JDO-652-api-patch-Andy.txt, JDO-652-patch3.txt,
> 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
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