org.apache.flink.cep.nfa.sharedbuffer.EventId Java Examples

/**
 * 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);
	}
}
 

/**
 * Extracts all the sequences of events from the start to the given computation state. An event
 * sequence is returned as a map which contains the events and the names of the states to which
 * the events were mapped.
 *
 * @param sharedBufferAccessor The accessor to {@link SharedBuffer} from which to extract the matches
 * @param computationState The end computation state of the extracted event sequences
 * @return Collection of event sequences which end in the given computation state
 * @throws Exception Thrown if the system cannot access the state.
 */
private Map<String, List<EventId>> extractCurrentMatches(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final ComputationState computationState) throws Exception {
	if (computationState.getPreviousBufferEntry() == null) {
		return new HashMap<>();
	}

	List<Map<String, List<EventId>>> paths = sharedBufferAccessor.extractPatterns(
			computationState.getPreviousBufferEntry(),
			computationState.getVersion());

	if (paths.isEmpty()) {
		return new HashMap<>();
	}
	// for a given computation state, we cannot have more than one matching patterns.
	Preconditions.checkState(paths.size() == 1);

	return paths.get(0);
}
 

/**
 * Extracts all the sequences of events from the start to the given computation state. An event
 * sequence is returned as a map which contains the events and the names of the states to which
 * the events were mapped.
 *
 * @param sharedBufferAccessor The accessor to {@link SharedBuffer} from which to extract the matches
 * @param computationState The end computation state of the extracted event sequences
 * @return Collection of event sequences which end in the given computation state
 * @throws Exception Thrown if the system cannot access the state.
 */
private Map<String, List<EventId>> extractCurrentMatches(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final ComputationState computationState) throws Exception {
	if (computationState.getPreviousBufferEntry() == null) {
		return new HashMap<>();
	}

	List<Map<String, List<EventId>>> paths = sharedBufferAccessor.extractPatterns(
			computationState.getPreviousBufferEntry(),
			computationState.getVersion());

	if (paths.isEmpty()) {
		return new HashMap<>();
	}
	// for a given computation state, we cannot have more than one matching patterns.
	Preconditions.checkState(paths.size() == 1);

	return paths.get(0);
}
 

/**
 * Extracts all the sequences of events from the start to the given computation state. An event
 * sequence is returned as a map which contains the events and the names of the states to which
 * the events were mapped.
 *
 * @param sharedBufferAccessor The accessor to {@link SharedBuffer} from which to extract the matches
 * @param computationState The end computation state of the extracted event sequences
 * @return Collection of event sequences which end in the given computation state
 * @throws Exception Thrown if the system cannot access the state.
 */
private Map<String, List<EventId>> extractCurrentMatches(
		final SharedBufferAccessor<T> sharedBufferAccessor,
		final ComputationState computationState) throws Exception {
	if (computationState.getPreviousBufferEntry() == null) {
		return new HashMap<>();
	}

	List<Map<String, List<EventId>>> paths = sharedBufferAccessor.extractPatterns(
			computationState.getPreviousBufferEntry(),
			computationState.getVersion());

	if (paths.isEmpty()) {
		return new HashMap<>();
	}
	// for a given computation state, we cannot have more than one matching patterns.
	Preconditions.checkState(paths.size() == 1);

	return paths.get(0);
}
 

static <T> Queue<ComputationState> deserializeComputationStates(
		org.apache.flink.cep.nfa.SharedBuffer<T> sharedBuffer,
		TypeSerializer<T> eventSerializer,
		DataInputView source) throws IOException {

	Queue<ComputationState> computationStates = new LinkedList<>();
	StringSerializer stateNameSerializer = StringSerializer.INSTANCE;
	LongSerializer timestampSerializer = LongSerializer.INSTANCE;
	DeweyNumber.DeweyNumberSerializer versionSerializer = DeweyNumber.DeweyNumberSerializer.INSTANCE;

	int computationStateNo = source.readInt();
	for (int i = 0; i < computationStateNo; i++) {
		String state = stateNameSerializer.deserialize(source);
		String prevState = stateNameSerializer.deserialize(source);
		long timestamp = timestampSerializer.deserialize(source);
		DeweyNumber version = versionSerializer.deserialize(source);
		long startTimestamp = timestampSerializer.deserialize(source);
		int counter = source.readInt();

		T event = null;
		if (source.readBoolean()) {
			event = eventSerializer.deserialize(source);
		}

		NodeId nodeId;
		EventId startEventId;
		if (prevState != null) {
			nodeId = sharedBuffer.getNodeId(prevState, timestamp, counter, event);
			startEventId = sharedBuffer.getStartEventId(version.getRun());
		} else {
			nodeId = null;
			startEventId = null;
		}

		computationStates.add(ComputationState.createState(state, nodeId, version, startTimestamp, startEventId));
	}
	return computationStates;
}
 

@Override
protected EventId getPruningId(Collection<Map<String, List<EventId>>> match) {
	EventId pruningId = null;
	for (Map<String, List<EventId>> resultMap : match) {
		List<EventId> pruningPattern = resultMap.get(patternName);
		if (pruningPattern == null || pruningPattern.isEmpty()) {
			if (shouldThrowException) {
				throw new FlinkRuntimeException(String.format(
					"Could not skip to %s. No such element in the found match %s",
					patternName,
					resultMap));
			}
		} else {
			pruningId = max(pruningId, pruningPattern.get(getIndex(pruningPattern.size())));
		}

		if (shouldThrowException) {
			EventId startEvent = resultMap.values()
				.stream()
				.flatMap(Collection::stream)
				.min(EventId::compareTo)
				.orElseThrow(() -> new IllegalStateException("Cannot prune based on empty match"));

			if (pruningId != null && pruningId.equals(startEvent)) {
				throw new FlinkRuntimeException("Could not skip to first element of a match.");
			}
		}
	}

	return pruningId;
}
 

@Override
protected EventId getPruningId(final Collection<Map<String, List<EventId>>> match) {
	EventId pruningId = null;
	for (Map<String, List<EventId>> resultMap : match) {
		for (List<EventId> eventList : resultMap.values()) {
			pruningId = max(pruningId, eventList.get(eventList.size() - 1));
		}
	}

	return pruningId;
}
 

public SharedBuffer(
		Map<EventId, Lockable<V>> eventsBuffer,
		Map<NodeId, Lockable<SharedBufferNode>> pages,
		Map<Tuple2<String, ValueTimeWrapper<V>>, NodeId> mappingContext,
		Map<Integer, EventId> starters) {

	this.eventsBuffer = eventsBuffer;
	this.pages = pages;
	this.mappingContext = mappingContext;
	this.starters = starters;
}
 

NFAStateSerializer(
		final TypeSerializer<DeweyNumber> versionSerializer,
		final TypeSerializer<NodeId> nodeIdSerializer,
		final TypeSerializer<EventId> eventIdSerializer) {
	this.versionSerializer = checkNotNull(versionSerializer);
	this.nodeIdSerializer = checkNotNull(nodeIdSerializer);
	this.eventIdSerializer = checkNotNull(eventIdSerializer);
}
 

private ComputationState deserializeSingleComputationState(DataInputView source) throws IOException {
	String stateName = StringValue.readString(source);
	NodeId prevState = nodeIdSerializer.deserialize(source);
	DeweyNumber version = versionSerializer.deserialize(source);
	long startTimestamp = source.readLong();

	EventId startEventId = deserializeStartEvent(source);

	return ComputationState.createState(stateName,
		prevState,
		version,
		startTimestamp,
		startEventId);
}
 

@Override
public SharedBufferNode createTestData() {
	SharedBufferNode result = new SharedBufferNode();
	result.addEdge(new SharedBufferEdge(
			new NodeId(new EventId(42, 42L), "page"),
			new DeweyNumber(42)));
	return result;
}
 

private void serializeStartEvent(EventId startEventID, DataOutputView target) throws IOException {
	if (startEventID != null) {
		target.writeByte(1);
		eventIdSerializer.serialize(startEventID, target);
	} else {
		target.writeByte(0);
	}
}
 

@Override
protected EventId getPruningId(final Collection<Map<String, List<EventId>>> match) {
	EventId pruningId = null;
	for (Map<String, List<EventId>> resultMap : match) {
		for (List<EventId> eventList : resultMap.values()) {
			pruningId = min(pruningId, eventList.get(0));
		}
	}

	return pruningId;
}
 

private EventId deserializeStartEvent(DataInputView source) throws IOException {
	byte isNull = source.readByte();
	EventId startEventId = null;
	if (isNull == 1) {
		startEventId = eventIdSerializer.deserialize(source);
	}
	return startEventId;
}
 

private void copyStartEvent(DataInputView source, DataOutputView target) throws IOException {
	byte isNull = source.readByte();
	target.writeByte(isNull);

	if (isNull == 1) {
		EventId startEventId = eventIdSerializer.deserialize(source);
		eventIdSerializer.serialize(startEventId, target);
	}
}
 

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
	in.defaultReadObject();

	// the nested serializer will be null if this was read from a savepoint taken with versions
	// lower than Flink 1.7; in this case, we explicitly create instance for the nested serializer.
	if (versionSerializer == null || nodeIdSerializer == null || eventIdSerializer == null) {
		this.versionSerializer = DeweyNumber.DeweyNumberSerializer.INSTANCE;
		this.eventIdSerializer = EventId.EventIdSerializer.INSTANCE;
		this.nodeIdSerializer = new NodeId.NodeIdSerializer();
	}
}
 

private ComputationState(
		final String currentState,
		@Nullable final NodeId previousBufferEntry,
		final DeweyNumber version,
		@Nullable final EventId startEventID,
		final long startTimestamp) {
	this.currentStateName = currentState;
	this.version = version;
	this.startTimestamp = startTimestamp;
	this.previousBufferEntry = previousBufferEntry;
	this.startEventID = startEventID;
}
 

static EventId max(EventId o1, EventId o2) {
	if (o2 == null) {
		return o1;
	}

	if (o1 == null) {
		return o2;
	}

	if (o1.compareTo(o2) >= 0) {
		return o1;
	} else {
		return o2;
	}
}
 

@Override
protected EventId getPruningId(final Collection<Map<String, List<EventId>>> match) {
	EventId pruningId = null;
	for (Map<String, List<EventId>> resultMap : match) {
		for (List<EventId> eventList : resultMap.values()) {
			pruningId = max(pruningId, eventList.get(eventList.size() - 1));
		}
	}

	return pruningId;
}
 

static EventId min(EventId o1, EventId o2) {
	if (o2 == null) {
		return o1;
	}

	if (o1 == null) {
		return o2;
	}

	if (o1.compareTo(o2) <= 0) {
		return o1;
	} else {
		return o2;
	}
}
 

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
	in.defaultReadObject();

	// the nested serializer will be null if this was read from a savepoint taken with versions
	// lower than Flink 1.7; in this case, we explicitly create instance for the nested serializer.
	if (versionSerializer == null || nodeIdSerializer == null || eventIdSerializer == null) {
		this.versionSerializer = DeweyNumber.DeweyNumberSerializer.INSTANCE;
		this.eventIdSerializer = EventId.EventIdSerializer.INSTANCE;
		this.nodeIdSerializer = new NodeId.NodeIdSerializer();
	}
}
 

private void copyStartEvent(DataInputView source, DataOutputView target) throws IOException {
	byte isNull = source.readByte();
	target.writeByte(isNull);

	if (isNull == 1) {
		EventId startEventId = eventIdSerializer.deserialize(source);
		eventIdSerializer.serialize(startEventId, target);
	}
}
 

private EventId deserializeStartEvent(DataInputView source) throws IOException {
	byte isNull = source.readByte();
	EventId startEventId = null;
	if (isNull == 1) {
		startEventId = eventIdSerializer.deserialize(source);
	}
	return startEventId;
}
 

private void serializeStartEvent(EventId startEventID, DataOutputView target) throws IOException {
	if (startEventID != null) {
		target.writeByte(1);
		eventIdSerializer.serialize(startEventID, target);
	} else {
		target.writeByte(0);
	}
}
 

private ComputationState deserializeSingleComputationState(DataInputView source) throws IOException {
	String stateName = StringValue.readString(source);
	NodeId prevState = nodeIdSerializer.deserialize(source);
	DeweyNumber version = versionSerializer.deserialize(source);
	long startTimestamp = source.readLong();

	EventId startEventId = deserializeStartEvent(source);

	return ComputationState.createState(stateName,
		prevState,
		version,
		startTimestamp,
		startEventId);
}
 

private void addComputationState(
		SharedBufferAccessor<T> sharedBufferAccessor,
		List<ComputationState> computationStates,
		State<T> currentState,
		NodeId previousEntry,
		DeweyNumber version,
		long startTimestamp,
		EventId startEventId) throws Exception {
	ComputationState computationState = ComputationState.createState(
			currentState.getName(), previousEntry, version, startTimestamp, startEventId);
	computationStates.add(computationState);

	sharedBufferAccessor.lockNode(previousEntry);
}
 

EventId getEventId() throws Exception {
	if (eventId == null) {
		this.eventId = sharedBufferAccessor.registerEvent(event, timestamp);
	}

	return eventId;
}
 

EventId getEventId() throws Exception {
	if (eventId == null) {
		this.eventId = sharedBufferAccessor.registerEvent(event, timestamp);
	}

	return eventId;
}