[hibernate-dev] HSearch Projection queries & multiple fields with same name

Hi, we've found the following problem regarding projection queries when dealing with documents containing multiple fields with the same name. Let's say we add field "foo" with two different values to the same document: luceneOptions.addFieldToDocument("foo", "aaa", document); luceneOptions.addFieldToDocument("foo", "bbb", document); If we now do a projection query on field "foo", one would expect the resultset to contain exactly two results ({"aaa"} and {"bbb"}), but HSearch returns only a single result (the property value of the result is either "aaa" or "bbb", because Document.getFieldable("foo"), which is called in o.h.search.engine.impl.DocumentBuilderHelper, returns the first field that matches the given name). DocumentExtractor.extract() returns a single EntityInfo, but in order for it to properly handle projections as described in the previous paragraph, it should really be modified to return List<EntityInfo>. This sounds pretty reasonable when the query is projecting only a single field. When projecting multiple multi-valued fields, the resultset should actually return a cartesian product. This is one way of doing it. The other way of doing it is if we consider multiple fields with the same name as a single multi-valued field. When projecting such fields, the resultset would contain the same number of results as there are matching documents, with the projected value being a collection of all the values stored in the field. Actually, in CapeDwarf we need the cartesian product, as this is the way Google AppEngine does it. What do you guys think? Marko