add support to lucene module for converting a query to a Lucene QueryWrapperFilter

[mirkosertic]

It would be great to have an ability to convert a TypedQuery to a Lucene QueryWrapperFilter. This would enable us to convert queries with a "constant" and a "dynamic" part to a Filter for the "constant" conditions and reuse it between different filters. This would greatly improve query performance in Lucene4. The AbstractLuceneQuery. createQuery() Method is private, so i am not able to implement this functionality by subclassing or delegation.

[mirkosertic]

Another option could be to add something like a "const" method to a filter predicate. Then we can use the dsl to express the static and dynamic parts and QueryDSL could internally create a query with the corresponding filter.

[timowest]

AbstractLuceneQuery.createQuery() is private. Maybe filter access could be provided on the AbstractLuceneQuery level instead?

Something like this maybe

public Filter asFilter() {
    return new QueryWrapperFilter(createQuery());
}

or alternatively just make the access of createQuery public?

[mirkosertic]

The asFilter implementation looks pretty good. From a Lucene point of view we should only use filters if we want to reuse them, so probably it would make sense to always return a CachingWrapperFilter instance. For further enhancements it would be cool to have the createQuery() method with protected visibility, so subclasses can access it.

By the way: what would be the best way to create unit tests for TypedQueries? Should i rely on toString() or should i assert the created Lucene query?

[timowest]

By the way: what would be the best way to create unit tests for TypedQueries? Should i rely on toString() or should i assert the created Lucene query?

Probably assert the created Lucene query.

[mirkosertic]

So protected acces for createQuery() makes perfect sense, or even public access...

[timowest]

Released in 3.2.4