Package org.apache.beam.runners.fnexecution.state

Class StateRequestHandlers

java.lang.Object

org.apache.beam.runners.fnexecution.state.StateRequestHandlers

public class StateRequestHandlers
extends Object

A set of utility methods which construct StateRequestHandlers.

TODO: Add a variant which works on ByteStrings to remove encoding/decoding overhead.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	StateRequestHandlers.BagUserStateHandler<K,V,W extends BoundedWindow>	A handler for bag user state.
static interface	StateRequestHandlers.BagUserStateHandlerFactory<K,V,W extends BoundedWindow>	A factory which constructs StateRequestHandlers.BagUserStateHandlers.
static interface	StateRequestHandlers.IterableSideInputHandler<V,W extends BoundedWindow>	A handler for iterable side inputs.
static interface	StateRequestHandlers.MultimapSideInputHandler<K,V,W extends BoundedWindow>	A handler for multimap side inputs.
static interface	StateRequestHandlers.SideInputHandler	Marker interface that denotes some type of side input handler.
static interface	StateRequestHandlers.SideInputHandlerFactory	A factory which constructs StateRequestHandlers.MultimapSideInputHandlers.

Constructor Summary

Constructors

Constructor	Description
StateRequestHandlers()

Method Summary

Modifier and Type	Method	Description
static StateRequestHandler	delegateBasedUponType(EnumMap<org.apache.beam.model.fnexecution.v1.BeamFnApi.StateKey.TypeCase,StateRequestHandler> handlers)	Returns a StateRequestHandler which delegates to the supplied handler depending on the BeamFnApi.StateRequests type.
static StateRequestHandler	forBagUserStateHandlerFactory(ProcessBundleDescriptors.ExecutableProcessBundleDescriptor processBundleDescriptor, StateRequestHandlers.BagUserStateHandlerFactory bagUserStateHandlerFactory)	Returns an adapter which converts a StateRequestHandlers.BagUserStateHandlerFactory to a StateRequestHandler.
static StateRequestHandler	forSideInputHandlerFactory(Map<String,Map<String,ProcessBundleDescriptors.SideInputSpec>> sideInputSpecs, StateRequestHandlers.SideInputHandlerFactory sideInputHandlerFactory)	Returns an adapter which converts a StateRequestHandlers.SideInputHandlerFactory to a StateRequestHandler.

Methods inherited from class java.lang.Object

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

Constructor Details

StateRequestHandlers

public StateRequestHandlers()

Method Details

delegateBasedUponType

public static StateRequestHandler delegateBasedUponType(EnumMap<org.apache.beam.model.fnexecution.v1.BeamFnApi.StateKey.TypeCase,StateRequestHandler> handlers)

Returns a StateRequestHandler which delegates to the supplied handler depending on the BeamFnApi.StateRequests type.

An exception is thrown if a corresponding handler is not found.

forSideInputHandlerFactory

public static StateRequestHandler forSideInputHandlerFactory(Map<String,Map<String,ProcessBundleDescriptors.SideInputSpec>> sideInputSpecs,
 StateRequestHandlers.SideInputHandlerFactory sideInputHandlerFactory)

Returns an adapter which converts a StateRequestHandlers.SideInputHandlerFactory to a StateRequestHandler.

The StateRequestHandlers.SideInputHandlerFactory is required to handle all side inputs contained within the ProcessBundleDescriptors.ExecutableProcessBundleDescriptor. See ProcessBundleDescriptors.ExecutableProcessBundleDescriptor.getSideInputSpecs() for the set of side inputs that are contained.

Instances of StateRequestHandlers.MultimapSideInputHandlers returned by the StateRequestHandlers.SideInputHandlerFactory are cached.

forBagUserStateHandlerFactory

public static StateRequestHandler forBagUserStateHandlerFactory(ProcessBundleDescriptors.ExecutableProcessBundleDescriptor processBundleDescriptor,
 StateRequestHandlers.BagUserStateHandlerFactory bagUserStateHandlerFactory)

Returns an adapter which converts a StateRequestHandlers.BagUserStateHandlerFactory to a StateRequestHandler.

The StateRequestHandlers.SideInputHandlerFactory is required to handle all multimap side inputs contained within the ProcessBundleDescriptors.ExecutableProcessBundleDescriptor. See ProcessBundleDescriptors.ExecutableProcessBundleDescriptor.getSideInputSpecs() for the set of multimap side inputs that are contained.

Instances of StateRequestHandlers.MultimapSideInputHandlers returned by the StateRequestHandlers.SideInputHandlerFactory are cached.

In case of any failures, this handler must be discarded. Otherwise, the contained state cache token would be reused which would corrupt the state cache.