Package org.apache.flink.api.java.typeutils.runtime

Class PojoSerializerSnapshot<T>

java.lang.Object

org.apache.flink.api.java.typeutils.runtime.PojoSerializerSnapshot<T>

All Implemented Interfaces:

TypeSerializerSnapshot<T>

@Internal
public class PojoSerializerSnapshot<T>
extends Object
implements TypeSerializerSnapshot<T>

Snapshot class for the PojoSerializer.

Constructor Summary

Constructors

Constructor	Description
PojoSerializerSnapshot()	Constructor for reading the snapshot.

Method Summary

Modifier and Type	Method	Description
int	getCurrentVersion()	Returns the version of the current snapshot's written binary format.
void	readSnapshot(int readVersion, DataInputView in, ClassLoader userCodeClassLoader)	Reads the serializer snapshot from the provided DataInputView.
TypeSerializerSchemaCompatibility<T>	resolveSchemaCompatibility(TypeSerializerSnapshot<T> oldSerializerSnapshot)	Checks current serializer's compatibility to read data written by the prior serializer.
TypeSerializer<T>	restoreSerializer()	Recreates a serializer instance from this snapshot.
void	writeSnapshot(DataOutputView out)	Writes the serializer snapshot to the provided DataOutputView.

Methods inherited from class java.lang.Object

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

Constructor Detail

PojoSerializerSnapshot

public PojoSerializerSnapshot()

Constructor for reading the snapshot.

Method Detail

getCurrentVersion

public int getCurrentVersion()

Description copied from interface: TypeSerializerSnapshot

Returns the version of the current snapshot's written binary format.

Specified by:

getCurrentVersion in interface TypeSerializerSnapshot<T>

Returns:

the version of the current snapshot's written binary format.

writeSnapshot

public void writeSnapshot(DataOutputView out)
                   throws IOException

Description copied from interface: TypeSerializerSnapshot

Writes the serializer snapshot to the provided DataOutputView. The current version of the written serializer snapshot's binary format is specified by the TypeSerializerSnapshot.getCurrentVersion() method.

Specified by:

writeSnapshot in interface TypeSerializerSnapshot<T>

Parameters:

out - the DataOutputView to write the snapshot to.

Throws:

IOException - Thrown if the snapshot data could not be written.

See Also:

TypeSerializerSnapshot.writeVersionedSnapshot(DataOutputView, TypeSerializerSnapshot)

readSnapshot

public void readSnapshot(int readVersion,
                         DataInputView in,
                         ClassLoader userCodeClassLoader)
                  throws IOException

Description copied from interface: TypeSerializerSnapshot

Reads the serializer snapshot from the provided DataInputView. The version of the binary format that the serializer snapshot was written with is provided. This version can be used to determine how the serializer snapshot should be read.

Specified by:

readSnapshot in interface TypeSerializerSnapshot<T>

Parameters:

readVersion - version of the serializer snapshot's written binary format

in - the DataInputView to read the snapshot from.

userCodeClassLoader - the user code classloader

Throws:

IOException - Thrown if the snapshot data could be read or parsed.

See Also:

TypeSerializerSnapshot.readVersionedSnapshot(DataInputView, ClassLoader)

restoreSerializer

public TypeSerializer<T> restoreSerializer()

Description copied from interface: TypeSerializerSnapshot

Recreates a serializer instance from this snapshot. The returned serializer can be safely used to read data written by the prior serializer (i.e., the serializer that created this snapshot).

Specified by:

restoreSerializer in interface TypeSerializerSnapshot<T>

Returns:

a serializer instance restored from this serializer snapshot.

resolveSchemaCompatibility

public TypeSerializerSchemaCompatibility<T> resolveSchemaCompatibility(TypeSerializerSnapshot<T> oldSerializerSnapshot)

Description copied from interface: TypeSerializerSnapshot

Checks current serializer's compatibility to read data written by the prior serializer.

When a checkpoint/savepoint is restored, this method checks whether the serialization format of the data in the checkpoint/savepoint is compatible for the format of the serializer used by the program that restores the checkpoint/savepoint. The outcome can be that the serialization format is compatible, that the program's serializer needs to reconfigure itself (meaning to incorporate some information from the TypeSerializerSnapshot to be compatible), that the format is outright incompatible, or that a migration needed. In the latter case, the TypeSerializerSnapshot produces a serializer to deserialize the data, and the restoring program's serializer re-serializes the data, thus converting the format during the restore operation.

This method must be implemented to clarify the compatibility. See FLIP-263 for more details.

Specified by:

resolveSchemaCompatibility in interface TypeSerializerSnapshot<T>

Parameters:

oldSerializerSnapshot - the old serializer snapshot to check.

Returns:

the serializer compatibility result.