org.apache.flink.runtime.state

Interface StateHandle<T>

All Superinterfaces:

Serializable

All Known Implementing Classes:

ByteStreamStateHandle, FileStateHandle, LocalStateHandle

public interface StateHandle<T>
extends Serializable

StateHandle is a general handle interface meant to abstract operator state fetching. A StateHandle implementation can for example include the state itself in cases where the state is lightweight or fetching it lazily from some external storage when the state is too large.

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.
T	getState() This retrieves and return the state represented by the handle.

Method Detail

getState

T getState()
    throws Exception

This retrieves and return the state represented by the handle.

Returns:

The state represented by the handle.

Throws:

Exception - Thrown, if the state cannot be fetched.

discardState

void discardState()
           throws Exception

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.

Throws:

Exception