/** * Output an instance after filtering but do not remove from the output queue. * * @return the instance that has most recently been filtered (or null if the queue is empty). * @throws NullPointerException if no input structure has been defined */ public Instance outputPeek() { if (m_OutputFormat == null) { throw new NullPointerException("No output instance format defined"); } if (m_OutputQueue.empty()) { return null; } Instance result = (Instance) m_OutputQueue.peek(); return result; }