org.apache.flink.contrib.streaming.state

Class DbStateHandle<S>

java.lang.Object

org.apache.flink.contrib.streaming.state.DbStateHandle<S>

All Implemented Interfaces:

Serializable, StateHandle<S>

public class DbStateHandle<S>
extends Object
implements Serializable, StateHandle<S>

State handle implementation for storing checkpoints as byte arrays in databases using the MySqlAdapter defined in the DbBackendConfig.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
DbStateHandle(String jobId, long checkpointId, long checkpointTs, long handleId, DbBackendConfig dbConfig, long stateSize)

Method Summary

Modifier and Type	Method and Description
void	discardState() Discards the state referred to by this handle, to free up resources in the persistent storage.
protected byte[]	getBytes()
S	getState(ClassLoader userCodeClassLoader) This retrieves and return the state represented by the handle.
long	getStateSize() Returns the size of the state in bytes.

Methods inherited from class java.lang.Object

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

Constructor Detail

DbStateHandle

public DbStateHandle(String jobId,
                     long checkpointId,
                     long checkpointTs,
                     long handleId,
                     DbBackendConfig dbConfig,
                     long stateSize)

Method Detail

getBytes

protected byte[] getBytes()
                   throws IOException

Throws:

IOException

discardState

public void discardState()

Description copied from interface: StateHandle

Discards the state referred to by this handle, to free up resources in the persistent storage. This method is called when the handle will not be used any more.

Specified by:

discardState in interface StateHandle<S>

getState

public S getState(ClassLoader userCodeClassLoader)
           throws IOException,
                  ClassNotFoundException

Description copied from interface: StateHandle

This retrieves and return the state represented by the handle.

Specified by:

getState in interface StateHandle<S>

Parameters:

userCodeClassLoader - Class loader for deserializing user code specific classes

Returns:

The state represented by the handle.

Throws:

IOException

ClassNotFoundException

getStateSize

public long getStateSize()

Description copied from interface: StateHandle

Returns the size of the state in bytes.

If the the size is not known, return 0.

Specified by:

getStateSize in interface StateHandle<S>

Returns:

Size of the state in bytes.