Editing support for JPQL queries in orm.xml files.

orm.xml or any <mapping-file> referenced from persistence.xml can contain JPQ (<named-query><query>) or SQL (<named-native-query><query>).

It would be a great advantage if there was tooling support available for editing JPQL in these files. A minimum feature set could include:

• Auto completion of entities in e.g. the FROM clause (in "SELECT ... FROM Entity entity", editor should be able to autocomplete Entity here)
• Navigate into entities (in above fragment, ctrl-clicking on Entity would open Entity.java)
• Auto completion of JPQL variables. (After the above fragment, editor should be able to autocomplete entity in "WHERE entity = ...")

As a more advanced feature, the editor could validate whether the entire JPQL is syntactical correct.

A nice to have would also include support for <named-native-query>, but as the syntax here is DB dependent and its usage may be relatively rare this is probably not very high on the wish list of many.