org.apache.flink.api.common.typeutils.base

Class TypeSerializerSingleton<T>

java.lang.Object

org.apache.flink.api.common.typeutils.TypeSerializer<T>

org.apache.flink.api.common.typeutils.base.TypeSerializerSingleton<T>

All Implemented Interfaces:

Serializable, TypeDeserializer<T>

Direct Known Subclasses:

BigDecSerializer, BigIntSerializer, BooleanPrimitiveArraySerializer, BooleanSerializer, BooleanValueSerializer, BytePrimitiveArraySerializer, ByteSerializer, ByteValueSerializer, CharPrimitiveArraySerializer, CharSerializer, CharValueSerializer, DateSerializer, DoublePrimitiveArraySerializer, DoubleSerializer, DoubleValueSerializer, FloatPrimitiveArraySerializer, FloatSerializer, FloatValueSerializer, IntPrimitiveArraySerializer, IntSerializer, IntValueSerializer, LongPrimitiveArraySerializer, LongSerializer, LongValueSerializer, NullValueSerializer, ShortPrimitiveArraySerializer, ShortSerializer, ShortValueSerializer, SqlDateSerializer, SqlTimeSerializer, SqlTimestampSerializer, StringArraySerializer, StringSerializer, StringValueSerializer, VoidSerializer

@Internal
public abstract class TypeSerializerSingleton<T>
extends TypeSerializer<T>

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
TypeSerializerSingleton()

Method Summary

Methods

Modifier and Type	Method and Description
TypeSerializerSingleton<T>	duplicate() Creates a deep copy of this serializer if it is necessary, i.e.
CompatibilityResult<T>	ensureCompatibility(TypeSerializerConfigSnapshot configSnapshot) Ensure compatibility of this serializer with a preceding serializer that was registered for serialization of the same managed state (if any - this method is only relevant if this serializer is registered for serialization of managed state).
boolean	equals(Object obj)
int	hashCode()
protected boolean	isCompatibleSerializationFormatIdentifier(String identifier) Subclasses can override this if they know that they are also compatible with identifiers of other formats.
TypeSerializerConfigSnapshot	snapshotConfiguration() Create a snapshot of the serializer's current configuration to be stored along with the managed state it is registered to (if any - this method is only relevant if this serializer is registered for serialization of managed state).

Methods inherited from class org.apache.flink.api.common.typeutils.TypeSerializer

canEqual, copy, copy, copy, createInstance, deserialize, deserialize, getLength, isImmutableType, serialize

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TypeSerializerSingleton

public TypeSerializerSingleton()

Method Detail

duplicate

public TypeSerializerSingleton<T> duplicate()

Description copied from class: TypeSerializer

Creates a deep copy of this serializer if it is necessary, i.e. if it is stateful. This can return itself if the serializer is not stateful. We need this because Serializers might be used in several threads. Stateless serializers are inherently thread-safe while stateful serializers might not be thread-safe.

Specified by:

duplicate in interface TypeDeserializer<T>

Specified by:

duplicate in class TypeSerializer<T>

hashCode

public int hashCode()

Specified by:

hashCode in interface TypeDeserializer<T>

Specified by:

hashCode in class TypeSerializer<T>

equals

public boolean equals(Object obj)

Specified by:

equals in interface TypeDeserializer<T>

Specified by:

equals in class TypeSerializer<T>

snapshotConfiguration

public TypeSerializerConfigSnapshot snapshotConfiguration()

Description copied from class: TypeSerializer

Create a snapshot of the serializer's current configuration to be stored along with the managed state it is registered to (if any - this method is only relevant if this serializer is registered for serialization of managed state).

The configuration snapshot should contain information about the serializer's parameter settings and its serialization format. When a new serializer is registered to serialize the same managed state that this serializer was registered to, the returned configuration snapshot can be used to ensure compatibility of the new serializer and determine if state migration is required.

Specified by:

snapshotConfiguration in class TypeSerializer<T>

Returns:

snapshot of the serializer's current configuration (cannot be null).

See Also:

TypeSerializerConfigSnapshot

ensureCompatibility

public CompatibilityResult<T> ensureCompatibility(TypeSerializerConfigSnapshot configSnapshot)

Description copied from class: TypeSerializer

Ensure compatibility of this serializer with a preceding serializer that was registered for serialization of the same managed state (if any - this method is only relevant if this serializer is registered for serialization of managed state). The compatibility check in this method should be performed by inspecting the preceding serializer's configuration snapshot. The method may reconfigure the serializer (if required and possible) so that it may be compatible, or provide a signaling result that informs Flink that state migration is necessary before continuing to use this serializer.

The result can be one of the following:

• CompatibilityResult.compatible(): this signals Flink that this serializer is compatible, or has been reconfigured to be compatible, to continue reading previous data, and that the serialization schema remains the same. No migration needs to be performed.
• CompatibilityResult.requiresMigration(TypeDeserializer): this signals Flink that migration needs to be performed, because this serializer is not compatible, or cannot be reconfigured to be compatible, for previous data. Furthermore, in the case that the preceding serializer cannot be found or restored to read the previous data to perform the migration, the provided convert deserializer can be used as a fallback resort.
• CompatibilityResult.requiresMigration(): this signals Flink that migration needs to be performed, because this serializer is not compatible, or cannot be reconfigured to be compatible, for previous data. If the preceding serializer cannot be found (either its implementation changed or it was removed from the classpath) then the migration will fail due to incapability to read previous data.

Specified by:

ensureCompatibility in class TypeSerializer<T>

Parameters:

configSnapshot - configuration snapshot of a preceding serializer for the same managed state

Returns:

the determined compatibility result (cannot be null).

See Also:

CompatibilityResult

isCompatibleSerializationFormatIdentifier

protected boolean isCompatibleSerializationFormatIdentifier(String identifier)

Subclasses can override this if they know that they are also compatible with identifiers of other formats.