/**
* 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;
}
