StateTags (Google Cloud Dataflow SDK 1.0.0 API)

java.lang.Object
- com.google.cloud.dataflow.sdk.util.state.StateTags

@Experimental(value=STATE)
public class StateTags
extends Object

Static utility methods for creating StateTag instances.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <T> StateTag<BagState<T>>`	`bag(String id, Coder<T> elemCoder)` Create a state tag that is optimized for adding values frequently, and occasionally retrieving all the values that have been added.
`static <InputT,AccumT,OutputT> StateTag<CombiningValueState<InputT,OutputT>>`	`combiningValue(String id, Coder<AccumT> accumCoder, Combine.CombineFn<InputT,AccumT,OutputT> combineFn)` Create a state tag for values that use a `Combine.CombineFn` to automatically merge multiple `InputT`s into a single `OutputT`.
`static <InputT,AccumT,OutputT> StateTag<CombiningValueState<InputT,OutputT>>`	`combiningValueFromInputInternal(String id, Coder<InputT> inputCoder, Combine.CombineFn<InputT,AccumT,OutputT> combineFn)` Create a state tag for values that use a `Combine.CombineFn` to automatically merge multiple `InputT`s into a single `OutputT`.
`static <StateT extends State> StateTag<StateT>`	`makeSystemTagInternal(StateTag<StateT> tag)` Convert an arbitrary `StateTag` to a system-internal tag that is guaranteed not to collide with any user tags.
`static <T> StateTag<ValueState<T>>`	`value(String id, Coder<T> valueCoder)` Create a simple state tag for values of type `T`.
`static <T> StateTag<WatermarkStateInternal>`	`watermarkStateInternal(String id)` Create a state tag for holding the watermark.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

value

public static <T> StateTag<ValueState<T>> value(String id,
                                                Coder<T> valueCoder)

Create a simple state tag for values of type T.

combiningValue

public static <InputT,AccumT,OutputT> StateTag<CombiningValueState<InputT,OutputT>> combiningValue(String id,
                                                                                                   Coder<AccumT> accumCoder,
                                                                                                   Combine.CombineFn<InputT,AccumT,OutputT> combineFn)

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

combiningValueFromInputInternal

public static <InputT,AccumT,OutputT> StateTag<CombiningValueState<InputT,OutputT>> combiningValueFromInputInternal(String id,
                                                                                                                    Coder<InputT> inputCoder,
                                                                                                                    Combine.CombineFn<InputT,AccumT,OutputT> combineFn)

Create a state tag 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.

bag

public static <T> StateTag<BagState<T>> bag(String id,
                                            Coder<T> elemCoder)

Create a state tag that is optimized for adding values frequently, and occasionally retrieving all the values that have been added.

watermarkStateInternal

public static <T> StateTag<WatermarkStateInternal> watermarkStateInternal(String id)

Create a state tag for holding the watermark.

makeSystemTagInternal
```
public static <StateT extends State> StateTag<StateT> makeSystemTagInternal(StateTag<StateT> tag)
```
Convert an arbitrary StateTag to a system-internal tag that is guaranteed not to collide with any user tags.

Class StateTags