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https://issues.apache.org/jira/browse/JDO-736?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14521298#comment-14521298
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Tilmann Zäschke commented on JDO-736:
-------------------------------------
Instead of having all these methods in the Query API, would it make sense to
move them into a separate class 'QueryProjector' or so?
Query.java would get have only one additional method <T>
execute(QueryProjector<T> def);
I think of something like the factory or builder pattern
To allow flow-style programming, one could use:
MyClass t = QueryProjector.executeUnique(pm.newQuery(Myclass.class));
or
List<MyResultClass> list = QueryProjector.executeList(ResultClass.class,
pm.newQuery(Myclass.class));
This would allow to maintain different projections for the same query. Would
that be useful?
Another solution to the unique() problem would be to return a dedicated result
class, such as QueryResult.
QueryResult qr = query.execute();
MyClass o = qr.getUniqe(); //returns the result or 'null', may also close the
query result
Query result would also implement List<>, so it could be used as follows:
for (MyClass o: qr) {
//do something
}
> Change Query API to make use of generics to avoid casting execute() results
> ---------------------------------------------------------------------------
>
> Key: JDO-736
> URL: https://issues.apache.org/jira/browse/JDO-736
> Project: JDO
> Issue Type: New Feature
> Components: api, specification, tck
> Reporter: Andy Jefferson
> Fix For: JDO 3.2
>
>
> The query API is dated, requiring casting of results to the required type.
> Let's make use of generics etc and remove the pain. This will mean changing
> the API so that the resultClass (and possibly more) will need passing into
> the
> execute() method(s). Could also specify parameters via setter rather than
> just on the execute.
> See JDO-652 also, we need to have a consistent way of executing queries
> whether created using strings or typesafe, so that no casting of results is
> needed with either
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