@Override
public void build(PropFuncArg argSubject, Node predicate, PropFuncArg argObject, ExecutionContext execCxt)
{
super.build(argSubject, predicate, argObject, execCxt) ;
if ( getIndex(execCxt) == null )
throw new QueryBuildException("Index not found") ;
if ( argSubject.isList() && argSubject.getArgListSize() != 2 )
throw new QueryBuildException("Subject has "+argSubject.getArgList().size()+" elements, not 2: "+argSubject) ;
if ( argObject.isList() && (argObject.getArgListSize() != 2 && argObject.getArgListSize() != 3) )
throw new QueryBuildException("Object has "+argObject.getArgList().size()+" elements, not 2 or 3: "+argObject) ;
}