Java Code Examples for org.apache.flink.cep.nfa.sharedbuffer.SharedBufferAccessor#releaseNode()

/**
 * Prunes matches/partial matches based on the chosen strategy.
 *
 * @param matchesToPrune current partial matches
 * @param matchedResult  already completed matches
 * @param sharedBufferAccessor   accessor to corresponding shared buffer
 * @throws Exception thrown if could not access the state
 */
public void prune(
		Collection<ComputationState> matchesToPrune,
		Collection<Map<String, List<EventId>>> matchedResult,
		SharedBufferAccessor<?> sharedBufferAccessor) throws Exception {

	EventId pruningId = getPruningId(matchedResult);
	if (pruningId != null) {
		List<ComputationState> discardStates = new ArrayList<>();
		for (ComputationState computationState : matchesToPrune) {
			if (computationState.getStartEventID() != null &&
				shouldPrune(computationState.getStartEventID(), pruningId)) {
				sharedBufferAccessor.releaseNode(computationState.getPreviousBufferEntry());
				discardStates.add(computationState);
			}
		}
		matchesToPrune.removeAll(discardStates);
	}
}
 

/**
 * Prunes matches/partial matches based on the chosen strategy.
 *
 * @param matchesToPrune current partial matches
 * @param matchedResult  already completed matches
 * @param sharedBufferAccessor   accessor to corresponding shared buffer
 * @throws Exception thrown if could not access the state
 */
public void prune(
		Collection<ComputationState> matchesToPrune,
		Collection<Map<String, List<EventId>>> matchedResult,
		SharedBufferAccessor<?> sharedBufferAccessor) throws Exception {

	EventId pruningId = getPruningId(matchedResult);
	if (pruningId != null) {
		List<ComputationState> discardStates = new ArrayList<>();
		for (ComputationState computationState : matchesToPrune) {
			if (computationState.getStartEventID() != null &&
				shouldPrune(computationState.getStartEventID(), pruningId)) {
				sharedBufferAccessor.releaseNode(computationState.getPreviousBufferEntry());
				discardStates.add(computationState);
			}
		}
		matchesToPrune.removeAll(discardStates);
	}
}
 

/**
 * Prunes matches/partial matches based on the chosen strategy.
 *
 * @param matchesToPrune current partial matches
 * @param matchedResult  already completed matches
 * @param sharedBufferAccessor   accessor to corresponding shared buffer
 * @throws Exception thrown if could not access the state
 */
public void prune(
		Collection<ComputationState> matchesToPrune,
		Collection<Map<String, List<EventId>>> matchedResult,
		SharedBufferAccessor<?> sharedBufferAccessor) throws Exception {

	EventId pruningId = getPruningId(matchedResult);
	if (pruningId != null) {
		List<ComputationState> discardStates = new ArrayList<>();
		for (ComputationState computationState : matchesToPrune) {
			if (computationState.getStartEventID() != null &&
				shouldPrune(computationState.getStartEventID(), pruningId)) {
				sharedBufferAccessor.releaseNode(computationState.getPreviousBufferEntry());
				discardStates.add(computationState);
			}
		}
		matchesToPrune.removeAll(discardStates);
	}
}
 

/**
 * Prunes states assuming there will be no events with timestamp <b>lower</b> than the given one.
 * It clears the sharedBuffer and also emits all timed out partial matches.
 *
 * @param sharedBufferAccessor the accessor to SharedBuffer object that we need to work upon while processing
 * @param nfaState     The NFAState object that we need to affect while processing
 * @param timestamp    timestamp that indicates that there will be no more events with lower timestamp
 * @return all timed outed partial matches
 * @throws Exception Thrown if the system cannot access the state.
 */
public Collection<Tuple2<Map<String, List<T>>, Long>> advanceTime(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final NFAState nfaState,
		final long timestamp) throws Exception {

	final Collection<Tuple2<Map<String, List<T>>, Long>> timeoutResult = new ArrayList<>();
	final PriorityQueue<ComputationState> newPartialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);

	for (ComputationState computationState : nfaState.getPartialMatches()) {
		if (isStateTimedOut(computationState, timestamp)) {

			if (handleTimeout) {
				// extract the timed out event pattern
				Map<String, List<T>> timedOutPattern = sharedBufferAccessor.materializeMatch(extractCurrentMatches(
					sharedBufferAccessor,
					computationState));
				timeoutResult.add(Tuple2.of(timedOutPattern, computationState.getStartTimestamp() + windowTime));
			}

			sharedBufferAccessor.releaseNode(computationState.getPreviousBufferEntry());

			nfaState.setStateChanged();
		} else {
			newPartialMatches.add(computationState);
		}
	}

	nfaState.setNewPartialMatches(newPartialMatches);

	sharedBufferAccessor.advanceTime(timestamp);

	return timeoutResult;
}
 

/**
 * Prunes states assuming there will be no events with timestamp <b>lower</b> than the given one.
 * It clears the sharedBuffer and also emits all timed out partial matches.
 *
 * @param sharedBufferAccessor the accessor to SharedBuffer object that we need to work upon while processing
 * @param nfaState     The NFAState object that we need to affect while processing
 * @param timestamp    timestamp that indicates that there will be no more events with lower timestamp
 * @return all timed outed partial matches
 * @throws Exception Thrown if the system cannot access the state.
 */
public Collection<Tuple2<Map<String, List<T>>, Long>> advanceTime(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final NFAState nfaState,
		final long timestamp) throws Exception {

	final Collection<Tuple2<Map<String, List<T>>, Long>> timeoutResult = new ArrayList<>();
	final PriorityQueue<ComputationState> newPartialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);

	for (ComputationState computationState : nfaState.getPartialMatches()) {
		if (isStateTimedOut(computationState, timestamp)) {

			if (handleTimeout) {
				// extract the timed out event pattern
				Map<String, List<T>> timedOutPattern = sharedBufferAccessor.materializeMatch(extractCurrentMatches(
					sharedBufferAccessor,
					computationState));
				timeoutResult.add(Tuple2.of(timedOutPattern, computationState.getStartTimestamp() + windowTime));
			}

			sharedBufferAccessor.releaseNode(computationState.getPreviousBufferEntry());

			nfaState.setStateChanged();
		} else {
			newPartialMatches.add(computationState);
		}
	}

	nfaState.setNewPartialMatches(newPartialMatches);

	sharedBufferAccessor.advanceTime(timestamp);

	return timeoutResult;
}
 

/**
 * Prunes states assuming there will be no events with timestamp <b>lower</b> than the given one.
 * It clears the sharedBuffer and also emits all timed out partial matches.
 *
 * @param sharedBufferAccessor the accessor to SharedBuffer object that we need to work upon while processing
 * @param nfaState     The NFAState object that we need to affect while processing
 * @param timestamp    timestamp that indicates that there will be no more events with lower timestamp
 * @return all timed outed partial matches
 * @throws Exception Thrown if the system cannot access the state.
 */
public Collection<Tuple2<Map<String, List<T>>, Long>> advanceTime(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final NFAState nfaState,
		final long timestamp) throws Exception {

	final Collection<Tuple2<Map<String, List<T>>, Long>> timeoutResult = new ArrayList<>();
	final PriorityQueue<ComputationState> newPartialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);

	for (ComputationState computationState : nfaState.getPartialMatches()) {
		if (isStateTimedOut(computationState, timestamp)) {

			if (handleTimeout) {
				// extract the timed out event pattern
				Map<String, List<T>> timedOutPattern = sharedBufferAccessor.materializeMatch(extractCurrentMatches(
					sharedBufferAccessor,
					computationState));
				timeoutResult.add(Tuple2.of(timedOutPattern, computationState.getStartTimestamp() + windowTime));
			}

			sharedBufferAccessor.releaseNode(computationState.getPreviousBufferEntry());

			nfaState.setStateChanged();
		} else {
			newPartialMatches.add(computationState);
		}
	}

	nfaState.setNewPartialMatches(newPartialMatches);

	sharedBufferAccessor.advanceTime(timestamp);

	return timeoutResult;
}
 

private Collection<Map<String, List<T>>> doProcess(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final NFAState nfaState,
		final EventWrapper event,
		final AfterMatchSkipStrategy afterMatchSkipStrategy,
		final TimerService timerService) throws Exception {

	final PriorityQueue<ComputationState> newPartialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);
	final PriorityQueue<ComputationState> potentialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);

	// iterate over all current computations
	for (ComputationState computationState : nfaState.getPartialMatches()) {
		final Collection<ComputationState> newComputationStates = computeNextStates(
			sharedBufferAccessor,
			computationState,
			event,
			timerService);

		if (newComputationStates.size() != 1) {
			nfaState.setStateChanged();
		} else if (!newComputationStates.iterator().next().equals(computationState)) {
			nfaState.setStateChanged();
		}

		//delay adding new computation states in case a stop state is reached and we discard the path.
		final Collection<ComputationState> statesToRetain = new ArrayList<>();
		//if stop state reached in this path
		boolean shouldDiscardPath = false;
		for (final ComputationState newComputationState : newComputationStates) {

			if (isFinalState(newComputationState)) {
				potentialMatches.add(newComputationState);
			} else if (isStopState(newComputationState)) {
				//reached stop state. release entry for the stop state
				shouldDiscardPath = true;
				sharedBufferAccessor.releaseNode(newComputationState.getPreviousBufferEntry());
			} else {
				// add new computation state; it will be processed once the next event arrives
				statesToRetain.add(newComputationState);
			}
		}

		if (shouldDiscardPath) {
			// a stop state was reached in this branch. release branch which results in removing previous event from
			// the buffer
			for (final ComputationState state : statesToRetain) {
				sharedBufferAccessor.releaseNode(state.getPreviousBufferEntry());
			}
		} else {
			newPartialMatches.addAll(statesToRetain);
		}
	}

	if (!potentialMatches.isEmpty()) {
		nfaState.setStateChanged();
	}

	List<Map<String, List<T>>> result = new ArrayList<>();
	if (afterMatchSkipStrategy.isSkipStrategy()) {
		processMatchesAccordingToSkipStrategy(sharedBufferAccessor,
			nfaState,
			afterMatchSkipStrategy,
			potentialMatches,
			newPartialMatches,
			result);
	} else {
		for (ComputationState match : potentialMatches) {
			Map<String, List<T>> materializedMatch =
				sharedBufferAccessor.materializeMatch(
					sharedBufferAccessor.extractPatterns(
						match.getPreviousBufferEntry(),
						match.getVersion()).get(0)
				);

			result.add(materializedMatch);
			sharedBufferAccessor.releaseNode(match.getPreviousBufferEntry());
		}
	}

	nfaState.setNewPartialMatches(newPartialMatches);

	return result;
}
 

private void processMatchesAccordingToSkipStrategy(
		SharedBufferAccessor<T> sharedBufferAccessor,
		NFAState nfaState,
		AfterMatchSkipStrategy afterMatchSkipStrategy,
		PriorityQueue<ComputationState> potentialMatches,
		PriorityQueue<ComputationState> partialMatches,
		List<Map<String, List<T>>> result) throws Exception {

	nfaState.getCompletedMatches().addAll(potentialMatches);

	ComputationState earliestMatch = nfaState.getCompletedMatches().peek();

	if (earliestMatch != null) {

		ComputationState earliestPartialMatch;
		while (earliestMatch != null && ((earliestPartialMatch = partialMatches.peek()) == null ||
			isEarlier(earliestMatch, earliestPartialMatch))) {

			nfaState.setStateChanged();
			nfaState.getCompletedMatches().poll();
			List<Map<String, List<EventId>>> matchedResult =
				sharedBufferAccessor.extractPatterns(earliestMatch.getPreviousBufferEntry(), earliestMatch.getVersion());

			afterMatchSkipStrategy.prune(
				partialMatches,
				matchedResult,
				sharedBufferAccessor);

			afterMatchSkipStrategy.prune(
				nfaState.getCompletedMatches(),
				matchedResult,
				sharedBufferAccessor);

			result.add(sharedBufferAccessor.materializeMatch(matchedResult.get(0)));
			sharedBufferAccessor.releaseNode(earliestMatch.getPreviousBufferEntry());
			earliestMatch = nfaState.getCompletedMatches().peek();
		}

		nfaState.getPartialMatches().removeIf(pm -> pm.getStartEventID() != null && !partialMatches.contains(pm));
	}
}
 

private Collection<Map<String, List<T>>> doProcess(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final NFAState nfaState,
		final EventWrapper event,
		final AfterMatchSkipStrategy afterMatchSkipStrategy,
		final TimerService timerService) throws Exception {

	final PriorityQueue<ComputationState> newPartialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);
	final PriorityQueue<ComputationState> potentialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);

	// iterate over all current computations
	for (ComputationState computationState : nfaState.getPartialMatches()) {
		final Collection<ComputationState> newComputationStates = computeNextStates(
			sharedBufferAccessor,
			computationState,
			event,
			timerService);

		if (newComputationStates.size() != 1) {
			nfaState.setStateChanged();
		} else if (!newComputationStates.iterator().next().equals(computationState)) {
			nfaState.setStateChanged();
		}

		//delay adding new computation states in case a stop state is reached and we discard the path.
		final Collection<ComputationState> statesToRetain = new ArrayList<>();
		//if stop state reached in this path
		boolean shouldDiscardPath = false;
		for (final ComputationState newComputationState : newComputationStates) {

			if (isFinalState(newComputationState)) {
				potentialMatches.add(newComputationState);
			} else if (isStopState(newComputationState)) {
				//reached stop state. release entry for the stop state
				shouldDiscardPath = true;
				sharedBufferAccessor.releaseNode(newComputationState.getPreviousBufferEntry());
			} else {
				// add new computation state; it will be processed once the next event arrives
				statesToRetain.add(newComputationState);
			}
		}

		if (shouldDiscardPath) {
			// a stop state was reached in this branch. release branch which results in removing previous event from
			// the buffer
			for (final ComputationState state : statesToRetain) {
				sharedBufferAccessor.releaseNode(state.getPreviousBufferEntry());
			}
		} else {
			newPartialMatches.addAll(statesToRetain);
		}
	}

	if (!potentialMatches.isEmpty()) {
		nfaState.setStateChanged();
	}

	List<Map<String, List<T>>> result = new ArrayList<>();
	if (afterMatchSkipStrategy.isSkipStrategy()) {
		processMatchesAccordingToSkipStrategy(sharedBufferAccessor,
			nfaState,
			afterMatchSkipStrategy,
			potentialMatches,
			newPartialMatches,
			result);
	} else {
		for (ComputationState match : potentialMatches) {
			Map<String, List<T>> materializedMatch =
				sharedBufferAccessor.materializeMatch(
					sharedBufferAccessor.extractPatterns(
						match.getPreviousBufferEntry(),
						match.getVersion()).get(0)
				);

			result.add(materializedMatch);
			sharedBufferAccessor.releaseNode(match.getPreviousBufferEntry());
		}
	}

	nfaState.setNewPartialMatches(newPartialMatches);

	return result;
}
 

private void processMatchesAccordingToSkipStrategy(
		SharedBufferAccessor<T> sharedBufferAccessor,
		NFAState nfaState,
		AfterMatchSkipStrategy afterMatchSkipStrategy,
		PriorityQueue<ComputationState> potentialMatches,
		PriorityQueue<ComputationState> partialMatches,
		List<Map<String, List<T>>> result) throws Exception {

	nfaState.getCompletedMatches().addAll(potentialMatches);

	ComputationState earliestMatch = nfaState.getCompletedMatches().peek();

	if (earliestMatch != null) {

		ComputationState earliestPartialMatch;
		while (earliestMatch != null && ((earliestPartialMatch = partialMatches.peek()) == null ||
			isEarlier(earliestMatch, earliestPartialMatch))) {

			nfaState.setStateChanged();
			nfaState.getCompletedMatches().poll();
			List<Map<String, List<EventId>>> matchedResult =
				sharedBufferAccessor.extractPatterns(earliestMatch.getPreviousBufferEntry(), earliestMatch.getVersion());

			afterMatchSkipStrategy.prune(
				partialMatches,
				matchedResult,
				sharedBufferAccessor);

			afterMatchSkipStrategy.prune(
				nfaState.getCompletedMatches(),
				matchedResult,
				sharedBufferAccessor);

			result.add(sharedBufferAccessor.materializeMatch(matchedResult.get(0)));
			sharedBufferAccessor.releaseNode(earliestMatch.getPreviousBufferEntry());
			earliestMatch = nfaState.getCompletedMatches().peek();
		}

		nfaState.getPartialMatches().removeIf(pm -> pm.getStartEventID() != null && !partialMatches.contains(pm));
	}
}
 

private Collection<Map<String, List<T>>> doProcess(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final NFAState nfaState,
		final EventWrapper event,
		final AfterMatchSkipStrategy afterMatchSkipStrategy,
		final TimerService timerService) throws Exception {

	final PriorityQueue<ComputationState> newPartialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);
	final PriorityQueue<ComputationState> potentialMatches = new PriorityQueue<>(NFAState.COMPUTATION_STATE_COMPARATOR);

	// iterate over all current computations
	for (ComputationState computationState : nfaState.getPartialMatches()) {
		final Collection<ComputationState> newComputationStates = computeNextStates(
			sharedBufferAccessor,
			computationState,
			event,
			timerService);

		if (newComputationStates.size() != 1) {
			nfaState.setStateChanged();
		} else if (!newComputationStates.iterator().next().equals(computationState)) {
			nfaState.setStateChanged();
		}

		//delay adding new computation states in case a stop state is reached and we discard the path.
		final Collection<ComputationState> statesToRetain = new ArrayList<>();
		//if stop state reached in this path
		boolean shouldDiscardPath = false;
		for (final ComputationState newComputationState : newComputationStates) {

			if (isFinalState(newComputationState)) {
				potentialMatches.add(newComputationState);
			} else if (isStopState(newComputationState)) {
				//reached stop state. release entry for the stop state
				shouldDiscardPath = true;
				sharedBufferAccessor.releaseNode(newComputationState.getPreviousBufferEntry());
			} else {
				// add new computation state; it will be processed once the next event arrives
				statesToRetain.add(newComputationState);
			}
		}

		if (shouldDiscardPath) {
			// a stop state was reached in this branch. release branch which results in removing previous event from
			// the buffer
			for (final ComputationState state : statesToRetain) {
				sharedBufferAccessor.releaseNode(state.getPreviousBufferEntry());
			}
		} else {
			newPartialMatches.addAll(statesToRetain);
		}
	}

	if (!potentialMatches.isEmpty()) {
		nfaState.setStateChanged();
	}

	List<Map<String, List<T>>> result = new ArrayList<>();
	if (afterMatchSkipStrategy.isSkipStrategy()) {
		processMatchesAccordingToSkipStrategy(sharedBufferAccessor,
			nfaState,
			afterMatchSkipStrategy,
			potentialMatches,
			newPartialMatches,
			result);
	} else {
		for (ComputationState match : potentialMatches) {
			Map<String, List<T>> materializedMatch =
				sharedBufferAccessor.materializeMatch(
					sharedBufferAccessor.extractPatterns(
						match.getPreviousBufferEntry(),
						match.getVersion()).get(0)
				);

			result.add(materializedMatch);
			sharedBufferAccessor.releaseNode(match.getPreviousBufferEntry());
		}
	}

	nfaState.setNewPartialMatches(newPartialMatches);

	return result;
}
 

private void processMatchesAccordingToSkipStrategy(
		SharedBufferAccessor<T> sharedBufferAccessor,
		NFAState nfaState,
		AfterMatchSkipStrategy afterMatchSkipStrategy,
		PriorityQueue<ComputationState> potentialMatches,
		PriorityQueue<ComputationState> partialMatches,
		List<Map<String, List<T>>> result) throws Exception {

	nfaState.getCompletedMatches().addAll(potentialMatches);

	ComputationState earliestMatch = nfaState.getCompletedMatches().peek();

	if (earliestMatch != null) {

		ComputationState earliestPartialMatch;
		while (earliestMatch != null && ((earliestPartialMatch = partialMatches.peek()) == null ||
			isEarlier(earliestMatch, earliestPartialMatch))) {

			nfaState.setStateChanged();
			nfaState.getCompletedMatches().poll();
			List<Map<String, List<EventId>>> matchedResult =
				sharedBufferAccessor.extractPatterns(earliestMatch.getPreviousBufferEntry(), earliestMatch.getVersion());

			afterMatchSkipStrategy.prune(
				partialMatches,
				matchedResult,
				sharedBufferAccessor);

			afterMatchSkipStrategy.prune(
				nfaState.getCompletedMatches(),
				matchedResult,
				sharedBufferAccessor);

			result.add(sharedBufferAccessor.materializeMatch(matchedResult.get(0)));
			sharedBufferAccessor.releaseNode(earliestMatch.getPreviousBufferEntry());
			earliestMatch = nfaState.getCompletedMatches().peek();
		}

		nfaState.getPartialMatches().removeIf(pm -> pm.getStartEventID() != null && !partialMatches.contains(pm));
	}
}