[rules-users] Custom-Operator - No access to FactHandles?

Hello, some of our custom operators need to access already inserted facts at runtime. Therefore we extended org.drools.base.BaseEvaluator. The provide methods, i. e. public boolean evaluate(InternalWorkingMemory workingMemory, InternalReadAccessor extractor, Object object, FieldValue value), state, amongst others, a parameter "workingMemory" of type org.drools.common.InternalWorkingMemory. When calling workingMemory.getObjects() we receive a "UnsupportedOperationException". The question is whether it is possible to access facts in a KnwoledgeSession at runtime or not. Alternatively we could provide the objects in question as globals and call workingMemory.getGlobal(), but that seems to me like somewhat bad architecture. Any suggestions are welcome. Many thanks, -Matthias