org.apache.beam.sdk.state

Class StateSpecs

java.lang.Object

org.apache.beam.sdk.state.StateSpecs

@Experimental(value=STATE)
public class StateSpecs
extends java.lang.Object

Static methods for working with StateSpecs.

Method Summary

Modifier and Type	Method and Description
static <T> StateSpec<BagState<T>>	bag() Create a StateSpec for a BagState, optimized for adding values frequently and occasionally retrieving all the values that have been added.
static <T> StateSpec<BagState<T>>	bag(Coder<T> elemCoder) Identical to bag(), but with an element coder explicitly supplied.
static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>>	combining(Coder<AccumT> accumCoder, Combine.CombineFn<InputT,AccumT,OutputT> combineFn) Identical to #combining(CombineFn), but with an accumulator coder explicitly supplied.
static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>>	combining(Coder<AccumT> accumCoder, CombineWithContext.CombineFnWithContext<InputT,AccumT,OutputT> combineFn) For internal use only; no backwards compatibility guarantees
static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>>	combining(Combine.CombineFn<InputT,AccumT,OutputT> combineFn) Create a StateSpec for a CombiningState which uses a Combine.CombineFn to automatically merge multiple values of type InputT into a single resulting OutputT.
static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>>	combining(CombineWithContext.CombineFnWithContext<InputT,AccumT,OutputT> combineFn) For internal use only; no backwards compatibility guarantees
static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>>	combiningFromInputInternal(Coder<InputT> inputCoder, Combine.CombineFn<InputT,AccumT,OutputT> combineFn) For internal use only; no backwards-compatibility guarantees.
static <InputT,AccumT,OutputT> StateSpec<BagState<AccumT>>	convertToBagSpecInternal(StateSpec<CombiningState<InputT,AccumT,OutputT>> combiningSpec) For internal use only; no backwards-compatibility guarantees.
static <K,V> StateSpec<MapState<K,V>>	map() Create a StateSpec for a SetState, optimized for key lookups and writes.
static <K,V> StateSpec<MapState<K,V>>	map(Coder<K> keyCoder, Coder<V> valueCoder) Identical to map(), but with key and value coders explicitly supplied.
static <T> StateSpec<SetState<T>>	set() Create a StateSpec for a SetState, optimized for checking membership.
static <T> StateSpec<SetState<T>>	set(Coder<T> elemCoder) Identical to set(), but with an element coder explicitly supplied.
static <T> StateSpec<ValueState<T>>	value() Create a StateSpec for a single value of type T.
static <T> StateSpec<ValueState<T>>	value(Coder<T> valueCoder) Identical to value(), but with a coder explicitly supplied.
static StateSpec<WatermarkHoldState>	watermarkStateInternal(TimestampCombiner timestampCombiner) For internal use only; no backwards-compatibility guarantees.

Methods inherited from class java.lang.Object

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

Method Detail

value

public static <T> StateSpec<ValueState<T>> value()

Create a StateSpec for a single value of type T.

This method attempts to infer the accumulator coder automatically.

See Also:

value(Coder)

value

public static <T> StateSpec<ValueState<T>> value(Coder<T> valueCoder)

Identical to value(), but with a coder explicitly supplied.

If automatic coder inference fails, use this method.

combining

public static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>> combining(Combine.CombineFn<InputT,AccumT,OutputT> combineFn)

Create a StateSpec for a CombiningState which uses a Combine.CombineFn to automatically merge multiple values of type InputT into a single resulting OutputT.

This method attempts to infer the accumulator coder automatically.

See Also:

#combining(Coder, CombineFn)

combining

@Internal
public static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>> combining(CombineWithContext.CombineFnWithContext<InputT,AccumT,OutputT> combineFn)

For internal use only; no backwards compatibility guarantees

Create a StateSpec for a CombiningState which uses a CombineWithContext.CombineFnWithContext to automatically merge multiple values of type InputT into a single resulting OutputT.

This method attempts to infer the accumulator coder automatically.

See Also:

#combining(Coder, CombineFnWithContext)

combining

public static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>> combining(Coder<AccumT> accumCoder,
                                                                                                 Combine.CombineFn<InputT,AccumT,OutputT> combineFn)

Identical to #combining(CombineFn), but with an accumulator coder explicitly supplied.

If automatic coder inference fails, use this method.

combining

@Internal
public static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>> combining(Coder<AccumT> accumCoder,
                                                                                                           CombineWithContext.CombineFnWithContext<InputT,AccumT,OutputT> combineFn)

For internal use only; no backwards compatibility guarantees

Identical to #combining(CombineFnWithContext), but with an accumulator coder explicitly supplied.

If automatic coder inference fails, use this method.

bag

public static <T> StateSpec<BagState<T>> bag()

Create a StateSpec for a BagState, optimized for adding values frequently and occasionally retrieving all the values that have been added.

This method attempts to infer the element coder automatically.

See Also:

bag(Coder)

bag

public static <T> StateSpec<BagState<T>> bag(Coder<T> elemCoder)

Identical to bag(), but with an element coder explicitly supplied.

If automatic coder inference fails, use this method.

set

public static <T> StateSpec<SetState<T>> set()

Create a StateSpec for a SetState, optimized for checking membership.

This method attempts to infer the element coder automatically.

See Also:

set(Coder)

set

public static <T> StateSpec<SetState<T>> set(Coder<T> elemCoder)

Identical to set(), but with an element coder explicitly supplied.

If automatic coder inference fails, use this method.

map

public static <K,V> StateSpec<MapState<K,V>> map()

Create a StateSpec for a SetState, optimized for key lookups and writes.

This method attempts to infer the key and value coders automatically.

See Also:

map(Coder, Coder)

map

public static <K,V> StateSpec<MapState<K,V>> map(Coder<K> keyCoder,
                                                 Coder<V> valueCoder)

Identical to map(), but with key and value coders explicitly supplied.

If automatic coder inference fails, use this method.

combiningFromInputInternal

@Internal
public static <InputT,AccumT,OutputT> StateSpec<CombiningState<InputT,AccumT,OutputT>> combiningFromInputInternal(Coder<InputT> inputCoder,
                                                                                                                            Combine.CombineFn<InputT,AccumT,OutputT> combineFn)

For internal use only; no backwards-compatibility guarantees.

Create a state spec for values that use a Combine.CombineFn to automatically merge multiple InputTs into a single OutputT.

This determines the Coder<AccumT> from the given Coder<InputT>, and should only be used to initialize static values.

watermarkStateInternal

@Internal
public static StateSpec<WatermarkHoldState> watermarkStateInternal(TimestampCombiner timestampCombiner)

For internal use only; no backwards-compatibility guarantees.

Create a state spec for a watermark hold.

convertToBagSpecInternal

@Internal
public static <InputT,AccumT,OutputT> StateSpec<BagState<AccumT>> convertToBagSpecInternal(StateSpec<CombiningState<InputT,AccumT,OutputT>> combiningSpec)

For internal use only; no backwards-compatibility guarantees.

Convert a combining state spec to a bag of accumulators.