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 StateSpec<BagState<Row>>	rowBag(Schema schema) Create a StateSpec for a BagState, optimized for adding values frequently and occasionally retrieving all the values that have been added.
static StateSpec<MapState<Row,Row>>	rowMap(Schema keySchema, Schema valueSchema) Create a StateSpec for a SetState, optimized for key lookups and writes.
static StateSpec<SetState<Row>>	rowSet(Schema schema) Create a StateSpec for a SetState, optimized for checking membership.
static StateSpec<ValueState<Row>>	rowValue(Schema schema) Create a StateSpec for a row value with the specified schema.
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 value coder automatically.

If the value type has a schema registered, then the schema will be used to encode the values.

See Also:

value(Coder)

rowValue

public static StateSpec<ValueState<Row>> rowValue(Schema schema)

Create a StateSpec for a row value with the specified schema.

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.

If the element type has a schema registered, then the schema will be used to encode the values.

See Also:

bag(Coder)

rowBag

public static StateSpec<BagState<Row>> rowBag(Schema schema)

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

This method is for storing row elements with the given schema.

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.

If the element type has a schema registered, then the schema will be used to encode the values.

See Also:

set(Coder)

rowSet

public static StateSpec<SetState<Row>> rowSet(Schema schema)

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

This method is for storing row elements with the given schema.

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.

If the key and value types have schemas registered, then the schemas will be used to encode the elements.

See Also:

map(Coder, Coder)

rowMap

public static StateSpec<MapState<Row,Row>> rowMap(Schema keySchema,
                                                  Schema valueSchema)

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

This method is for storing maps where both the keys and the values are rows with the specified schemas.

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.