org.apache.flink.api.common.typeutils.base.ListSerializer Java Examples

@Override
public void initializeState(StateInitializationContext context) throws Exception {
	super.initializeState(context);

	// initializeState through the provided context
	computationStates = context.getKeyedStateStore().getState(
		new ValueStateDescriptor<>(
			NFA_STATE_NAME,
			new NFAStateSerializer()));

	partialMatches = new SharedBuffer<>(context.getKeyedStateStore(), inputSerializer);

	elementQueueState = context.getKeyedStateStore().getMapState(
			new MapStateDescriptor<>(
					EVENT_QUEUE_STATE_NAME,
					LongSerializer.INSTANCE,
					new ListSerializer<>(inputSerializer)));

	migrateOldState();
}
 

@Nullable
@Override
public List<TtlValue<T>> getUnexpiredOrNull(@Nonnull List<TtlValue<T>> ttlValues) {
	long currentTimestamp = timeProvider.currentTimestamp();
	List<TtlValue<T>> unexpired = new ArrayList<>(ttlValues.size());
	TypeSerializer<TtlValue<T>> elementSerializer =
		((ListSerializer<TtlValue<T>>) original.getValueSerializer()).getElementSerializer();
	for (TtlValue<T> ttlValue : ttlValues) {
		if (!TtlUtils.expired(ttlValue, ttl, currentTimestamp)) {
			// we have to do the defensive copy to update the value
			unexpired.add(elementSerializer.copy(ttlValue));
		}
	}
	if (!unexpired.isEmpty()) {
		return unexpired;
	} else {
		return ttlValues.size() == unexpired.size() ? ttlValues : unexpired;
	}
}
 

@Override
public void initializeState(StateInitializationContext context) throws Exception {
	super.initializeState(context);

	this.leftBuffer = context.getKeyedStateStore().getMapState(new MapStateDescriptor<>(
		LEFT_BUFFER,
		LongSerializer.INSTANCE,
		new ListSerializer<>(new BufferEntrySerializer<>(leftTypeSerializer))
	));

	this.rightBuffer = context.getKeyedStateStore().getMapState(new MapStateDescriptor<>(
		RIGHT_BUFFER,
		LongSerializer.INSTANCE,
		new ListSerializer<>(new BufferEntrySerializer<>(rightTypeSerializer))
	));
}
 

@Override
public void initializeState(StateInitializationContext context) throws Exception {
	super.initializeState(context);

	// initializeState through the provided context
	computationStates = context.getKeyedStateStore().getState(
		new ValueStateDescriptor<>(
			NFA_STATE_NAME,
			new NFAStateSerializer()));

	partialMatches = new SharedBuffer<>(context.getKeyedStateStore(), inputSerializer);

	elementQueueState = context.getKeyedStateStore().getMapState(
			new MapStateDescriptor<>(
					EVENT_QUEUE_STATE_NAME,
					LongSerializer.INSTANCE,
					new ListSerializer<>(inputSerializer)));

	migrateOldState();
}
 

@Test
public void testListStateDescriptor() throws Exception {

	TypeSerializer<String> serializer = new KryoSerializer<>(String.class, new ExecutionConfig());

	ListStateDescriptor<String> descr =
			new ListStateDescriptor<>("testName", serializer);

	assertEquals("testName", descr.getName());
	assertNotNull(descr.getSerializer());
	assertTrue(descr.getSerializer() instanceof ListSerializer);
	assertNotNull(descr.getElementSerializer());
	assertEquals(serializer, descr.getElementSerializer());

	ListStateDescriptor<String> copy = CommonTestUtils.createCopySerializable(descr);

	assertEquals("testName", copy.getName());
	assertNotNull(copy.getSerializer());
	assertTrue(copy.getSerializer() instanceof ListSerializer);

	assertNotNull(copy.getElementSerializer());
	assertEquals(serializer, copy.getElementSerializer());
}
 

private void validateListStateDescriptorConfigured(SingleOutputStreamOperator<?> result) {
	OneInputTransformation<?, ?> transform = (OneInputTransformation<?, ?>) result.getTransformation();
	WindowOperator<?, ?, ?, ?, ?> op = (WindowOperator<?, ?, ?, ?, ?>) transform.getOperator();
	StateDescriptor<?, ?> descr = op.getStateDescriptor();

	assertTrue(descr instanceof ListStateDescriptor);

	ListStateDescriptor<?> listDescr = (ListStateDescriptor<?>) descr;

	// this would be the first statement to fail if state descriptors were not properly initialized
	TypeSerializer<?> serializer = listDescr.getSerializer();
	assertTrue(serializer instanceof ListSerializer);

	TypeSerializer<?> elementSerializer = listDescr.getElementSerializer();
	assertTrue(elementSerializer instanceof KryoSerializer);

	Kryo kryo = ((KryoSerializer<?>) elementSerializer).getKryo();

	assertTrue("serializer registration was not properly passed on",
			kryo.getSerializer(File.class) instanceof JavaSerializer);
}
 

@Test
public void testListStateInstantiation() throws Exception {

	final ExecutionConfig config = new ExecutionConfig();
	config.registerKryoType(Path.class);

	final AtomicReference<Object> descriptorCapture = new AtomicReference<>();

	StreamingRuntimeContext context = createRuntimeContext(descriptorCapture, config);

	ListStateDescriptor<TaskInfo> descr = new ListStateDescriptor<>("name", TaskInfo.class);
	context.getListState(descr);

	ListStateDescriptor<?> descrIntercepted = (ListStateDescriptor<?>) descriptorCapture.get();
	TypeSerializer<?> serializer = descrIntercepted.getSerializer();

	// check that the Path class is really registered, i.e., the execution config was applied
	assertTrue(serializer instanceof ListSerializer);

	TypeSerializer<?> elementSerializer = descrIntercepted.getElementSerializer();
	assertTrue(elementSerializer instanceof KryoSerializer);
	assertTrue(((KryoSerializer<?>) elementSerializer).getKryo().getRegistration(Path.class).getId() > 0);
}
 

@Nullable
@Override
public List<TtlValue<T>> getUnexpiredOrNull(@Nonnull List<TtlValue<T>> ttlValues) {
	long currentTimestamp = timeProvider.currentTimestamp();
	List<TtlValue<T>> unexpired = new ArrayList<>(ttlValues.size());
	TypeSerializer<TtlValue<T>> elementSerializer =
		((ListSerializer<TtlValue<T>>) original.getValueSerializer()).getElementSerializer();
	for (TtlValue<T> ttlValue : ttlValues) {
		if (!TtlUtils.expired(ttlValue, ttl, currentTimestamp)) {
			// we have to do the defensive copy to update the value
			unexpired.add(elementSerializer.copy(ttlValue));
		}
	}
	if (!unexpired.isEmpty()) {
		return unexpired;
	} else {
		return ttlValues.size() == unexpired.size() ? ttlValues : unexpired;
	}
}
 

@Override
public void initializeState(StateInitializationContext context) throws Exception {
	super.initializeState(context);

	this.leftBuffer = context.getKeyedStateStore().getMapState(new MapStateDescriptor<>(
		LEFT_BUFFER,
		LongSerializer.INSTANCE,
		new ListSerializer<>(new BufferEntrySerializer<>(leftTypeSerializer))
	));

	this.rightBuffer = context.getKeyedStateStore().getMapState(new MapStateDescriptor<>(
		RIGHT_BUFFER,
		LongSerializer.INSTANCE,
		new ListSerializer<>(new BufferEntrySerializer<>(rightTypeSerializer))
	));
}
 

private void validateListStateDescriptorConfigured(SingleOutputStreamOperator<?> result) {
	OneInputTransformation<?, ?> transform = (OneInputTransformation<?, ?>) result.getTransformation();
	WindowOperator<?, ?, ?, ?, ?> op = (WindowOperator<?, ?, ?, ?, ?>) transform.getOperator();
	StateDescriptor<?, ?> descr = op.getStateDescriptor();

	assertTrue(descr instanceof ListStateDescriptor);

	ListStateDescriptor<?> listDescr = (ListStateDescriptor<?>) descr;

	// this would be the first statement to fail if state descriptors were not properly initialized
	TypeSerializer<?> serializer = listDescr.getSerializer();
	assertTrue(serializer instanceof ListSerializer);

	TypeSerializer<?> elementSerializer = listDescr.getElementSerializer();
	assertTrue(elementSerializer instanceof KryoSerializer);

	Kryo kryo = ((KryoSerializer<?>) elementSerializer).getKryo();

	assertTrue("serializer registration was not properly passed on",
			kryo.getSerializer(File.class) instanceof JavaSerializer);
}
 

@Test
public void testListStateInstantiation() throws Exception {

	final ExecutionConfig config = new ExecutionConfig();
	config.registerKryoType(Path.class);

	final AtomicReference<Object> descriptorCapture = new AtomicReference<>();

	StreamingRuntimeContext context = new StreamingRuntimeContext(
			createDescriptorCapturingMockOp(descriptorCapture, config),
			createMockEnvironment(),
			Collections.<String, Accumulator<?, ?>>emptyMap());

	ListStateDescriptor<TaskInfo> descr = new ListStateDescriptor<>("name", TaskInfo.class);
	context.getListState(descr);

	ListStateDescriptor<?> descrIntercepted = (ListStateDescriptor<?>) descriptorCapture.get();
	TypeSerializer<?> serializer = descrIntercepted.getSerializer();

	// check that the Path class is really registered, i.e., the execution config was applied
	assertTrue(serializer instanceof ListSerializer);

	TypeSerializer<?> elementSerializer = descrIntercepted.getElementSerializer();
	assertTrue(elementSerializer instanceof KryoSerializer);
	assertTrue(((KryoSerializer<?>) elementSerializer).getKryo().getRegistration(Path.class).getId() > 0);
}
 

@Test
public void testListStateDescriptor() throws Exception {

	TypeSerializer<String> serializer = new KryoSerializer<>(String.class, new ExecutionConfig());

	ListStateDescriptor<String> descr =
			new ListStateDescriptor<>("testName", serializer);

	assertEquals("testName", descr.getName());
	assertNotNull(descr.getSerializer());
	assertTrue(descr.getSerializer() instanceof ListSerializer);
	assertNotNull(descr.getElementSerializer());
	assertEquals(serializer, descr.getElementSerializer());

	ListStateDescriptor<String> copy = CommonTestUtils.createCopySerializable(descr);

	assertEquals("testName", copy.getName());
	assertNotNull(copy.getSerializer());
	assertTrue(copy.getSerializer() instanceof ListSerializer);

	assertNotNull(copy.getElementSerializer());
	assertEquals(serializer, copy.getElementSerializer());
}
 

@Test
public void testListStateInstantiation() throws Exception {

	final ExecutionConfig config = new ExecutionConfig();
	config.registerKryoType(Path.class);

	final AtomicReference<Object> descriptorCapture = new AtomicReference<>();

	StreamingRuntimeContext context = new StreamingRuntimeContext(
			createDescriptorCapturingMockOp(descriptorCapture, config),
			createMockEnvironment(),
			Collections.<String, Accumulator<?, ?>>emptyMap());

	ListStateDescriptor<TaskInfo> descr = new ListStateDescriptor<>("name", TaskInfo.class);
	context.getListState(descr);

	ListStateDescriptor<?> descrIntercepted = (ListStateDescriptor<?>) descriptorCapture.get();
	TypeSerializer<?> serializer = descrIntercepted.getSerializer();

	// check that the Path class is really registered, i.e., the execution config was applied
	assertTrue(serializer instanceof ListSerializer);

	TypeSerializer<?> elementSerializer = descrIntercepted.getElementSerializer();
	assertTrue(elementSerializer instanceof KryoSerializer);
	assertTrue(((KryoSerializer<?>) elementSerializer).getKryo().getRegistration(Path.class).getId() > 0);
}
 

private void validateListStateDescriptorConfigured(SingleOutputStreamOperator<?> result) {
	OneInputTransformation<?, ?> transform = (OneInputTransformation<?, ?>) result.getTransformation();
	WindowOperator<?, ?, ?, ?, ?> op = (WindowOperator<?, ?, ?, ?, ?>) transform.getOperator();
	StateDescriptor<?, ?> descr = op.getStateDescriptor();

	assertTrue(descr instanceof ListStateDescriptor);

	ListStateDescriptor<?> listDescr = (ListStateDescriptor<?>) descr;

	// this would be the first statement to fail if state descriptors were not properly initialized
	TypeSerializer<?> serializer = listDescr.getSerializer();
	assertTrue(serializer instanceof ListSerializer);

	TypeSerializer<?> elementSerializer = listDescr.getElementSerializer();
	assertTrue(elementSerializer instanceof KryoSerializer);

	Kryo kryo = ((KryoSerializer<?>) elementSerializer).getKryo();

	assertTrue("serializer registration was not properly passed on",
			kryo.getSerializer(File.class) instanceof JavaSerializer);
}
 

@Override
public void initializeState(StateInitializationContext context) throws Exception {
	super.initializeState(context);

	this.leftBuffer = context.getKeyedStateStore().getMapState(new MapStateDescriptor<>(
		LEFT_BUFFER,
		LongSerializer.INSTANCE,
		new ListSerializer<>(new BufferEntrySerializer<>(leftTypeSerializer))
	));

	this.rightBuffer = context.getKeyedStateStore().getMapState(new MapStateDescriptor<>(
		RIGHT_BUFFER,
		LongSerializer.INSTANCE,
		new ListSerializer<>(new BufferEntrySerializer<>(rightTypeSerializer))
	));
}
 

@Nullable
@Override
public List<TtlValue<T>> getUnexpiredOrNull(@Nonnull List<TtlValue<T>> ttlValues) {
	long currentTimestamp = timeProvider.currentTimestamp();
	List<TtlValue<T>> unexpired = new ArrayList<>(ttlValues.size());
	TypeSerializer<TtlValue<T>> elementSerializer =
		((ListSerializer<TtlValue<T>>) original.getValueSerializer()).getElementSerializer();
	for (TtlValue<T> ttlValue : ttlValues) {
		if (!TtlUtils.expired(ttlValue, ttl, currentTimestamp)) {
			// we have to do the defensive copy to update the value
			unexpired.add(elementSerializer.copy(ttlValue));
		}
	}
	if (!unexpired.isEmpty()) {
		return unexpired;
	} else {
		return ttlValues.size() == unexpired.size() ? ttlValues : unexpired;
	}
}
 

@Test
public void testListStateDescriptor() throws Exception {

	TypeSerializer<String> serializer = new KryoSerializer<>(String.class, new ExecutionConfig());

	ListStateDescriptor<String> descr =
			new ListStateDescriptor<>("testName", serializer);

	assertEquals("testName", descr.getName());
	assertNotNull(descr.getSerializer());
	assertTrue(descr.getSerializer() instanceof ListSerializer);
	assertNotNull(descr.getElementSerializer());
	assertEquals(serializer, descr.getElementSerializer());

	ListStateDescriptor<String> copy = CommonTestUtils.createCopySerializable(descr);

	assertEquals("testName", copy.getName());
	assertNotNull(copy.getSerializer());
	assertTrue(copy.getSerializer() instanceof ListSerializer);

	assertNotNull(copy.getElementSerializer());
	assertEquals(serializer, copy.getElementSerializer());
}
 

@Override
public void initializeState(StateInitializationContext context) throws Exception {
	super.initializeState(context);

	// initializeState through the provided context
	computationStates = context.getKeyedStateStore().getState(
		new ValueStateDescriptor<>(
			NFA_STATE_NAME,
			new NFAStateSerializer()));

	partialMatches = new SharedBuffer<>(context.getKeyedStateStore(), inputSerializer);

	elementQueueState = context.getKeyedStateStore().getMapState(
			new MapStateDescriptor<>(
					EVENT_QUEUE_STATE_NAME,
					LongSerializer.INSTANCE,
					new ListSerializer<>(inputSerializer)));

	migrateOldState();
}
 

@SuppressWarnings("unchecked")
@Override
public TypeSerializer<ListView<T>> createSerializer(ExecutionConfig config) {
	if (nullSerializer) {
		return (TypeSerializer<ListView<T>>) (TypeSerializer<?>) NullSerializer.INSTANCE;
	} else {
		TypeSerializer<T> elementSerializer = elementType.createSerializer(config);
		return new ListViewSerializer<>(new ListSerializer<>(elementSerializer));
	}
}
 

@Override
public byte[] getSerializedValue(
		final byte[] serializedKeyAndNamespace,
		final TypeSerializer<K> safeKeySerializer,
		final TypeSerializer<N> safeNamespaceSerializer,
		final TypeSerializer<List<V>> safeValueSerializer) throws Exception {

	Preconditions.checkNotNull(serializedKeyAndNamespace);
	Preconditions.checkNotNull(safeKeySerializer);
	Preconditions.checkNotNull(safeNamespaceSerializer);
	Preconditions.checkNotNull(safeValueSerializer);

	Tuple2<K, N> keyAndNamespace = KvStateSerializer.deserializeKeyAndNamespace(
			serializedKeyAndNamespace, safeKeySerializer, safeNamespaceSerializer);

	List<V> result = stateTable.get(keyAndNamespace.f0, keyAndNamespace.f1);

	if (result == null) {
		return null;
	}

	final TypeSerializer<V> dupSerializer = ((ListSerializer<V>) safeValueSerializer).getElementSerializer();

	ByteArrayOutputStream baos = new ByteArrayOutputStream();
	DataOutputViewStreamWrapper view = new DataOutputViewStreamWrapper(baos);

	// write the same as RocksDB writes lists, with one ',' separator
	for (int i = 0; i < result.size(); i++) {
		dupSerializer.serialize(result.get(i), view);
		if (i < result.size() -1) {
			view.writeByte(',');
		}
	}
	view.flush();

	return baos.toByteArray();
}
 

public void configCompactFilter(
		@Nonnull StateDescriptor<?, ?> stateDesc,
		TypeSerializer<?> stateSerializer) {
	StateTtlConfig ttlConfig = stateDesc.getTtlConfig();
	if (ttlConfig.isEnabled() && ttlConfig.getCleanupStrategies().inRocksdbCompactFilter()) {
		FlinkCompactionFilterFactory compactionFilterFactory = compactionFilterFactories.get(stateDesc.getName());
		Preconditions.checkNotNull(compactionFilterFactory);
		long ttl = ttlConfig.getTtl().toMilliseconds();

		StateTtlConfig.RocksdbCompactFilterCleanupStrategy rocksdbCompactFilterCleanupStrategy =
			ttlConfig.getCleanupStrategies().getRocksdbCompactFilterCleanupStrategy();
		Preconditions.checkNotNull(rocksdbCompactFilterCleanupStrategy);
		long queryTimeAfterNumEntries =
			rocksdbCompactFilterCleanupStrategy.getQueryTimeAfterNumEntries();

		FlinkCompactionFilter.Config config;
		if (stateDesc instanceof ListStateDescriptor) {
			TypeSerializer<?> elemSerializer = ((ListSerializer<?>) stateSerializer).getElementSerializer();
			int len = elemSerializer.getLength();
			if (len > 0) {
				config = FlinkCompactionFilter.Config.createForFixedElementList(
					ttl, queryTimeAfterNumEntries, len + 1); // plus one byte for list element delimiter
			} else {
				config = FlinkCompactionFilter.Config.createForList(
					ttl, queryTimeAfterNumEntries,
					new ListElementFilterFactory<>(elemSerializer.duplicate()));
			}
		} else if (stateDesc instanceof MapStateDescriptor) {
			config = FlinkCompactionFilter.Config.createForMap(ttl, queryTimeAfterNumEntries);
		} else {
			config = FlinkCompactionFilter.Config.createForValue(ttl, queryTimeAfterNumEntries);
		}
		compactionFilterFactory.configure(config);
	}
}
 

@Override
public void migrateSerializedValue(
		DataInputDeserializer serializedOldValueInput,
		DataOutputSerializer serializedMigratedValueOutput,
		TypeSerializer<List<V>> priorSerializer,
		TypeSerializer<List<V>> newSerializer) throws StateMigrationException {

	Preconditions.checkArgument(priorSerializer instanceof ListSerializer);
	Preconditions.checkArgument(newSerializer instanceof ListSerializer);

	TypeSerializer<V> priorElementSerializer =
		((ListSerializer<V>) priorSerializer).getElementSerializer();

	TypeSerializer<V> newElementSerializer =
		((ListSerializer<V>) newSerializer).getElementSerializer();

	try {
		while (serializedOldValueInput.available() > 0) {
			V element = deserializeNextElement(serializedOldValueInput, priorElementSerializer);
			newElementSerializer.serialize(element, serializedMigratedValueOutput);
			if (serializedOldValueInput.available() > 0) {
				serializedMigratedValueOutput.write(DELIMITER);
			}
		}
	} catch (Exception e) {
		throw new StateMigrationException("Error while trying to migrate RocksDB list state.", e);
	}
}
 

/**
 * Creates a new {@code RocksDBListState}.
 *
 * @param columnFamily The RocksDB column family that this state is associated to.
 * @param namespaceSerializer The serializer for the namespace.
 * @param valueSerializer The serializer for the state.
 * @param defaultValue The default value for the state.
 * @param backend The backend for which this state is bind to.
 */
private RocksDBListState(
		ColumnFamilyHandle columnFamily,
		TypeSerializer<N> namespaceSerializer,
		TypeSerializer<List<V>> valueSerializer,
		List<V> defaultValue,
		RocksDBKeyedStateBackend<K> backend) {

	super(columnFamily, namespaceSerializer, valueSerializer, defaultValue, backend);

	ListSerializer<V> castedListSerializer = (ListSerializer<V>) valueSerializer;
	this.elementSerializer = castedListSerializer.getElementSerializer();
}
 

public static boolean isTtlStateSerializer(TypeSerializer<?> typeSerializer) {
	boolean ttlSerializer = typeSerializer instanceof TtlStateFactory.TtlSerializer;
	boolean ttlListSerializer = typeSerializer instanceof ListSerializer &&
		((ListSerializer) typeSerializer).getElementSerializer() instanceof TtlStateFactory.TtlSerializer;
	boolean ttlMapSerializer = typeSerializer instanceof MapSerializer &&
		((MapSerializer) typeSerializer).getValueSerializer() instanceof TtlStateFactory.TtlSerializer;
	return ttlSerializer || ttlListSerializer || ttlMapSerializer;
}
 

public void configCompactFilter(
		@Nonnull StateDescriptor<?, ?> stateDesc,
		TypeSerializer<?> stateSerializer) {
	StateTtlConfig ttlConfig = stateDesc.getTtlConfig();
	if (ttlConfig.isEnabled() && ttlConfig.getCleanupStrategies().inRocksdbCompactFilter()) {
		if (!enableTtlCompactionFilter) {
			LOG.warn("Cannot configure RocksDB TTL compaction filter for state <{}>: " +
				"feature is disabled for the state backend.", stateDesc.getName());
			return;
		}
		FlinkCompactionFilterFactory compactionFilterFactory = compactionFilterFactories.get(stateDesc.getName());
		Preconditions.checkNotNull(compactionFilterFactory);
		long ttl = ttlConfig.getTtl().toMilliseconds();

		StateTtlConfig.RocksdbCompactFilterCleanupStrategy rocksdbCompactFilterCleanupStrategy =
			ttlConfig.getCleanupStrategies().getRocksdbCompactFilterCleanupStrategy();
		Preconditions.checkNotNull(rocksdbCompactFilterCleanupStrategy);
		long queryTimeAfterNumEntries =
			rocksdbCompactFilterCleanupStrategy.getQueryTimeAfterNumEntries();

		FlinkCompactionFilter.Config config;
		if (stateDesc instanceof ListStateDescriptor) {
			TypeSerializer<?> elemSerializer = ((ListSerializer<?>) stateSerializer).getElementSerializer();
			int len = elemSerializer.getLength();
			if (len > 0) {
				config = FlinkCompactionFilter.Config.createForFixedElementList(
					ttl, queryTimeAfterNumEntries, len + 1); // plus one byte for list element delimiter
			} else {
				config = FlinkCompactionFilter.Config.createForList(
					ttl, queryTimeAfterNumEntries,
					new ListElementFilterFactory<>(elemSerializer.duplicate()));
			}
		} else if (stateDesc instanceof MapStateDescriptor) {
			config = FlinkCompactionFilter.Config.createForMap(ttl, queryTimeAfterNumEntries);
		} else {
			config = FlinkCompactionFilter.Config.createForValue(ttl, queryTimeAfterNumEntries);
		}
		compactionFilterFactory.configure(config);
	}
}
 

public static boolean isTtlStateSerializer(TypeSerializer<?> typeSerializer) {
	boolean ttlSerializer = typeSerializer instanceof TtlStateFactory.TtlSerializer;
	boolean ttlListSerializer = typeSerializer instanceof ListSerializer &&
		((ListSerializer) typeSerializer).getElementSerializer() instanceof TtlStateFactory.TtlSerializer;
	boolean ttlMapSerializer = typeSerializer instanceof MapSerializer &&
		((MapSerializer) typeSerializer).getValueSerializer() instanceof TtlStateFactory.TtlSerializer;
	return ttlSerializer || ttlListSerializer || ttlMapSerializer;
}
 

@Override
public byte[] getSerializedValue(
		final byte[] serializedKeyAndNamespace,
		final TypeSerializer<K> safeKeySerializer,
		final TypeSerializer<N> safeNamespaceSerializer,
		final TypeSerializer<List<V>> safeValueSerializer) throws Exception {

	Preconditions.checkNotNull(serializedKeyAndNamespace);
	Preconditions.checkNotNull(safeKeySerializer);
	Preconditions.checkNotNull(safeNamespaceSerializer);
	Preconditions.checkNotNull(safeValueSerializer);

	Tuple2<K, N> keyAndNamespace = KvStateSerializer.deserializeKeyAndNamespace(
			serializedKeyAndNamespace, safeKeySerializer, safeNamespaceSerializer);

	List<V> result = stateTable.get(keyAndNamespace.f0, keyAndNamespace.f1);

	if (result == null) {
		return null;
	}

	final TypeSerializer<V> dupSerializer = ((ListSerializer<V>) safeValueSerializer).getElementSerializer();

	ByteArrayOutputStream baos = new ByteArrayOutputStream();
	DataOutputViewStreamWrapper view = new DataOutputViewStreamWrapper(baos);

	// write the same as RocksDB writes lists, with one ',' separator
	for (int i = 0; i < result.size(); i++) {
		dupSerializer.serialize(result.get(i), view);
		if (i < result.size() -1) {
			view.writeByte(',');
		}
	}
	view.flush();

	return baos.toByteArray();
}
 

@Override
public void migrateSerializedValue(
		DataInputDeserializer serializedOldValueInput,
		DataOutputSerializer serializedMigratedValueOutput,
		TypeSerializer<List<V>> priorSerializer,
		TypeSerializer<List<V>> newSerializer) throws StateMigrationException {

	Preconditions.checkArgument(priorSerializer instanceof ListSerializer);
	Preconditions.checkArgument(newSerializer instanceof ListSerializer);

	TypeSerializer<V> priorElementSerializer =
		((ListSerializer<V>) priorSerializer).getElementSerializer();

	TypeSerializer<V> newElementSerializer =
		((ListSerializer<V>) newSerializer).getElementSerializer();

	try {
		while (serializedOldValueInput.available() > 0) {
			V element = deserializeNextElement(serializedOldValueInput, priorElementSerializer);
			newElementSerializer.serialize(element, serializedMigratedValueOutput);
			if (serializedOldValueInput.available() > 0) {
				serializedMigratedValueOutput.write(DELIMITER);
			}
		}
	} catch (Exception e) {
		throw new StateMigrationException("Error while trying to migrate RocksDB list state.", e);
	}
}
 

@SuppressWarnings("unchecked")
static <SV, SEV> StateSnapshotTransformFactory<SV> wrapStateSnapshotTransformFactory(
	StateDescriptor<?, SV> stateDesc,
	StateSnapshotTransformFactory<SEV> snapshotTransformFactory,
	TypeSerializer<SV> stateSerializer) {
	if (stateDesc instanceof ListStateDescriptor) {
		TypeSerializer<SEV> elementSerializer = ((ListSerializer<SEV>) stateSerializer).getElementSerializer();
		return new RocksDBListStateSnapshotTransformFactory<>(snapshotTransformFactory, elementSerializer);
	} else if (stateDesc instanceof MapStateDescriptor) {
		return new RocksDBMapStateSnapshotTransformFactory<>(snapshotTransformFactory);
	} else {
		return new RocksDBValueStateSnapshotTransformFactory<>(snapshotTransformFactory);
	}
}
 

/**
 * Creates a new {@code RocksDBListState}.
 *
 * @param columnFamily The RocksDB column family that this state is associated to.
 * @param namespaceSerializer The serializer for the namespace.
 * @param valueSerializer The serializer for the state.
 * @param defaultValue The default value for the state.
 * @param backend The backend for which this state is bind to.
 */
private RocksDBListState(
		ColumnFamilyHandle columnFamily,
		TypeSerializer<N> namespaceSerializer,
		TypeSerializer<List<V>> valueSerializer,
		List<V> defaultValue,
		RocksDBKeyedStateBackend<K> backend) {

	super(columnFamily, namespaceSerializer, valueSerializer, defaultValue, backend);

	ListSerializer<V> castedListSerializer = (ListSerializer<V>) valueSerializer;
	this.elementSerializer = castedListSerializer.getElementSerializer();
}