com.google.cloud.dataflow.sdk.util.state

Interface StateTag<StateT extends State>

Type Parameters:

StateT - The type of state being tagged.

All Superinterfaces:

Serializable

@Experimental(value=STATE)
public interface StateTag<StateT extends State>
extends Serializable

An address for persistent state. This includes a unique identifier for the location, the information necessary to encode the value, and details about the intended access pattern.

State can be thought of as a sparse table, with each StateTag defining a column that has cells of type StateT.

Currently, this can only be used in a step immediately following a GroupByKey.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	StateTag.StateBinder Visitor for binding a StateTag and to the associated State.

Method Summary

Modifier and Type	Method and Description
StateT	bind(StateTag.StateBinder binder) Use the binder to create an instance of StateT appropriate for this address.
String	getId() Returns the identifier for this state cell.

Method Detail

getId

String getId()

Returns the identifier for this state cell.

bind

StateT bind(StateTag.StateBinder binder)

Use the binder to create an instance of StateT appropriate for this address.