private Tuple joinTuples(Tuple firstTuple, Tuple secondTuple) { Tuple joinedTuple = firstTuple.clone(); joinedTuple.setOid(new TupleOID(IntegerOIDGenerator.getNextOID())); joinedTuple.getCells().addAll(secondTuple.clone().getCells()); if (logger.isDebugEnabled()) logger.trace("Joined tuple: \n" + joinedTuple); return joinedTuple; }