Package org.apache.flink.api.common.typeutils

Class TypeSerializer<T>

    • Constructor Detail

      • TypeSerializer

        public TypeSerializer()

    • Method Detail

      • isImmutableType

        public abstract boolean isImmutableType()
        Gets whether the type is an immutable type.
        Returns:
        True, if the type is immutable.

      • duplicate

        public abstract TypeSerializer<T> duplicate()
        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.

      • createInstance

        public abstract T createInstance()
        Creates a new instance of the data type.
        Returns:
        A new instance of the data type.

      • copy

        public abstract T copy​(T from)
        Creates a deep copy of the given element in a new element.
        Parameters:
        from - The element reuse be copied.
        Returns:
        A deep copy of the element.

      • copy

        public abstract T copy​(T from,
                       T reuse)
        Creates a copy from the given element. The method makes an attempt to store the copy in the given reuse element, if the type is mutable. This is, however, not guaranteed.
        Parameters:
        from - The element to be copied.
        reuse - The element to be reused. May or may not be used.
        Returns:
        A deep copy of the element.

      • getLength

        public abstract int getLength()
        Gets the length of the data type, if it is a fix length data type.
        Returns:
        The length of the data type, or -1 for variable length data types.

      • serialize

        public abstract void serialize​(T record,
                               DataOutputView target)
                        throws IOException
        Serializes the given record to the given target output view.
        Parameters:
        record - The record to serialize.
        target - The output view to write the serialized data to.
        Throws:
        IOException - Thrown, if the serialization encountered an I/O related error. Typically raised by the output view, which may have an underlying I/O channel to which it delegates.

      • deserialize

        public abstract T deserialize​(DataInputView source)
                       throws IOException
        De-serializes a record from the given source input view.
        Parameters:
        source - The input view from which to read the data.
        Returns:
        The deserialized element.
        Throws:
        IOException - Thrown, if the de-serialization encountered an I/O related error. Typically raised by the input view, which may have an underlying I/O channel from which it reads.

      • deserialize

        public abstract T deserialize​(T reuse,
                              DataInputView source)
                       throws IOException
        De-serializes a record from the given source input view into the given reuse record instance if mutable.
        Parameters:
        reuse - The record instance into which to de-serialize the data.
        source - The input view from which to read the data.
        Returns:
        The deserialized element.
        Throws:
        IOException - Thrown, if the de-serialization encountered an I/O related error. Typically raised by the input view, which may have an underlying I/O channel from which it reads.

      • copy

        public abstract void copy​(DataInputView source,
                          DataOutputView target)
                   throws IOException
        Copies exactly one record from the source input view to the target output view. Whether this operation works on binary data or partially de-serializes the record to determine its length (such as for records of variable length) is up to the implementer. Binary copies are typically faster. A copy of a record containing two integer numbers (8 bytes total) is most efficiently implemented as target.write(source, 8);.
        Parameters:
        source - The input view from which to read the record.
        target - The target output view to which to write the record.
        Throws:
        IOException - Thrown if any of the two views raises an exception.

      • equals

        public abstract boolean equals​(Object obj)
        Overrides:
        equals in class Object

      • hashCode

        public abstract int hashCode()
        Overrides:
        hashCode in class Object

      • snapshotConfiguration

        public abstract TypeSerializerSnapshot<T> snapshotConfiguration()
        Snapshots the configuration of this TypeSerializer. This method is only relevant if the serializer is used to state stored in checkpoints/savepoints.

        The snapshot of the TypeSerializer is supposed to contain all information that affects the serialization format of the serializer. The snapshot serves two purposes: First, to reproduce the serializer when the checkpoint/savepoint is restored, and second, to check whether the serialization format is compatible with the serializer used in the restored program.

        IMPORTANT: TypeSerializerSnapshots changed after Flink 1.6. Serializers implemented against Flink versions up to 1.6 should still work, but adjust to new model to enable state evolution and be future-proof. See the class-level comments, section "Upgrading TypeSerializers to the new TypeSerializerSnapshot model" for details.

        Returns:
        snapshot of the serializer's current configuration (cannot be null).
        See Also:
        TypeSerializerSnapshot.resolveSchemaCompatibility(TypeSerializerSnapshot)