org.apache.flink.runtime.state.memory

Class MemCheckpointStreamFactory

java.lang.Object

org.apache.flink.runtime.state.memory.MemCheckpointStreamFactory

All Implemented Interfaces:

CheckpointStreamFactory

Direct Known Subclasses:

NonPersistentMetadataCheckpointStorageLocation, PersistentMetadataCheckpointStorageLocation

public class MemCheckpointStreamFactory
extends Object
implements CheckpointStreamFactory

CheckpointStreamFactory that produces streams that write to in-memory byte arrays.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MemCheckpointStreamFactory.MemoryCheckpointOutputStream A CheckpointStateOutputStream that writes into a byte array.

Constructor Summary

Constructors

Constructor and Description
MemCheckpointStreamFactory(int maxStateSize) Creates a new in-memory stream factory that accepts states whose serialized forms are up to the given number of bytes.

Method Summary

Modifier and Type	Method and Description
boolean	canFastDuplicate(StreamStateHandle stateHandle, CheckpointedStateScope scope) Tells if we can duplicate the given StreamStateHandle into the path corresponding to the given CheckpointedStateScope.
CheckpointStateOutputStream	createCheckpointStateOutputStream(CheckpointedStateScope scope) Creates an new CheckpointStateOutputStream.
List<StreamStateHandle>	duplicate(List<StreamStateHandle> stateHandles, CheckpointedStateScope scope) Duplicates StreamStateHandle into the path corresponding to * the given CheckpointedStateScope.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

MemCheckpointStreamFactory

public MemCheckpointStreamFactory(int maxStateSize)

Creates a new in-memory stream factory that accepts states whose serialized forms are up to the given number of bytes.

Parameters:

maxStateSize - The maximal size of the serialized state

Method Detail

createCheckpointStateOutputStream

public CheckpointStateOutputStream createCheckpointStateOutputStream(CheckpointedStateScope scope)
                                                              throws IOException

Description copied from interface: CheckpointStreamFactory

Creates an new CheckpointStateOutputStream. When the stream is closed, it returns a state handle that can retrieve the state back.

Specified by:

createCheckpointStateOutputStream in interface CheckpointStreamFactory

Parameters:

scope - The state's scope, whether it is exclusive or shared.

Returns:

An output stream that writes state for the given checkpoint.

Throws:

IOException - Exceptions may occur while creating the stream and should be forwarded.

canFastDuplicate

public boolean canFastDuplicate(StreamStateHandle stateHandle,
                                CheckpointedStateScope scope)

Description copied from interface: CheckpointStreamFactory

Tells if we can duplicate the given StreamStateHandle into the path corresponding to the given CheckpointedStateScope.

This should be a rather cheap operation, preferably not involving any remote accesses.

Specified by:

canFastDuplicate in interface CheckpointStreamFactory

Parameters:

stateHandle - The handle to duplicate

scope - Scope determining the location to duplicate into

Returns:

true, if we can perform the duplication

duplicate

public List<StreamStateHandle> duplicate(List<StreamStateHandle> stateHandles,
                                         CheckpointedStateScope scope)
                                  throws IOException

Description copied from interface: CheckpointStreamFactory

Duplicates StreamStateHandle into the path corresponding to * the given CheckpointedStateScope.

You should first check if you can duplicate with CheckpointStreamFactory.canFastDuplicate(StreamStateHandle, CheckpointedStateScope).

Specified by:

duplicate in interface CheckpointStreamFactory

Parameters:

stateHandles - The handles to duplicate

scope - Scope determining the location to duplicate into

Returns:

The duplicated handle

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object