org.apache.flink.streaming.util.serialization

Class TypeInformationKeyValueSerializationSchema<K,V>

java.lang.Object

org.apache.flink.streaming.util.serialization.TypeInformationKeyValueSerializationSchema<K,V>

Type Parameters:

K - The key type to be serialized.

V - The value type to be serialized.

All Implemented Interfaces:

Serializable, ResultTypeQueryable<Tuple2<K,V>>, KeyedDeserializationSchema<Tuple2<K,V>>, KeyedSerializationSchema<Tuple2<K,V>>

@Internal
public class TypeInformationKeyValueSerializationSchema<K,V>
extends Object
implements KeyedDeserializationSchema<Tuple2<K,V>>, KeyedSerializationSchema<Tuple2<K,V>>

A serialization and deserialization schema for Key Value Pairs that uses Flink's serialization stack to transform typed from and to byte arrays.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
TypeInformationKeyValueSerializationSchema(Class<K> keyClass, Class<V> valueClass, ExecutionConfig config) Creates a new de-/serialization schema for the given types.
TypeInformationKeyValueSerializationSchema(TypeInformation<K> keyTypeInfo, TypeInformation<V> valueTypeInfo, ExecutionConfig ec) Creates a new de-/serialization schema for the given types.

Method Summary

Modifier and Type	Method and Description
Tuple2<K,V>	deserialize(byte[] messageKey, byte[] message, String topic, int partition, long offset) Deserializes the byte message.
TypeInformation<Tuple2<K,V>>	getProducedType() Gets the data type (as a TypeInformation) produced by this function or input format.
String	getTargetTopic(Tuple2<K,V> element) Optional method to determine the target topic for the element.
boolean	isEndOfStream(Tuple2<K,V> nextElement) This schema never considers an element to signal end-of-stream, so this method returns always false.
byte[]	serializeKey(Tuple2<K,V> element) Serializes the key of the incoming element to a byte array This method might return null if no key is available.
byte[]	serializeValue(Tuple2<K,V> element) Serializes the value of the incoming element to a byte array.

Methods inherited from class java.lang.Object

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

Constructor Detail

TypeInformationKeyValueSerializationSchema

public TypeInformationKeyValueSerializationSchema(TypeInformation<K> keyTypeInfo,
                                                  TypeInformation<V> valueTypeInfo,
                                                  ExecutionConfig ec)

Creates a new de-/serialization schema for the given types.

Parameters:

keyTypeInfo - The type information for the key type de-/serialized by this schema.

valueTypeInfo - The type information for the value type de-/serialized by this schema.

ec - The execution config, which is used to parametrize the type serializers.

TypeInformationKeyValueSerializationSchema

public TypeInformationKeyValueSerializationSchema(Class<K> keyClass,
                                                  Class<V> valueClass,
                                                  ExecutionConfig config)

Creates a new de-/serialization schema for the given types. This constructor accepts the types as classes and internally constructs the type information from the classes.

If the types are parametrized and cannot be fully defined via classes, use the constructor that accepts TypeInformation instead.

Parameters:

keyClass - The class of the key de-/serialized by this schema.

valueClass - The class of the value de-/serialized by this schema.

config - The execution config, which is used to parametrize the type serializers.

Method Detail

deserialize

public Tuple2<K,V> deserialize(byte[] messageKey,
                               byte[] message,
                               String topic,
                               int partition,
                               long offset)
                        throws IOException

Description copied from interface: KeyedDeserializationSchema

Deserializes the byte message.

Specified by:

deserialize in interface KeyedDeserializationSchema<Tuple2<K,V>>

Parameters:

messageKey - the key as a byte array (null if no key has been set).

message - The message, as a byte array (null if the message was empty or deleted).

partition - The partition the message has originated from.

offset - the offset of the message in the original source (for example the Kafka offset).

Returns:

The deserialized message as an object (null if the message cannot be deserialized).

Throws:

IOException

isEndOfStream

public boolean isEndOfStream(Tuple2<K,V> nextElement)

This schema never considers an element to signal end-of-stream, so this method returns always false.

Specified by:

isEndOfStream in interface KeyedDeserializationSchema<Tuple2<K,V>>

Parameters:

nextElement - The element to test for the end-of-stream signal.

Returns:

Returns false.

serializeKey

public byte[] serializeKey(Tuple2<K,V> element)

Description copied from interface: KeyedSerializationSchema

Serializes the key of the incoming element to a byte array This method might return null if no key is available.

Specified by:

serializeKey in interface KeyedSerializationSchema<Tuple2<K,V>>

Parameters:

element - The incoming element to be serialized

Returns:

the key of the element as a byte array

serializeValue

public byte[] serializeValue(Tuple2<K,V> element)

Description copied from interface: KeyedSerializationSchema

Serializes the value of the incoming element to a byte array.

Specified by:

serializeValue in interface KeyedSerializationSchema<Tuple2<K,V>>

Parameters:

element - The incoming element to be serialized

Returns:

the value of the element as a byte array

getTargetTopic

public String getTargetTopic(Tuple2<K,V> element)

Description copied from interface: KeyedSerializationSchema

Optional method to determine the target topic for the element.

Specified by:

getTargetTopic in interface KeyedSerializationSchema<Tuple2<K,V>>

Parameters:

element - Incoming element to determine the target topic from

Returns:

null or the target topic

getProducedType

public TypeInformation<Tuple2<K,V>> getProducedType()

Description copied from interface: ResultTypeQueryable

Gets the data type (as a TypeInformation) produced by this function or input format.

Specified by:

getProducedType in interface ResultTypeQueryable<Tuple2<K,V>>

Returns:

The data type produced by this function or input format.