com.google.cloud.dataflow.sdk.transforms

Interface DoFn.KeyedState

Enclosing class:

DoFn<I,O>

public static interface DoFn.KeyedState

Interface for interacting with keyed state.

This functionality is experimental and likely to change.

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	lookup(CodedTupleTag<T> tag) Returns the value associated with the given tag in this KeyedState, or null if the tag has no asssociated value.
CodedTupleTagMap	lookup(java.util.List<? extends CodedTupleTag<?>> tags) Returns a map from the given tags to the values associated with those tags in this KeyedState.
<T> void	store(CodedTupleTag<T> tag, T value) Updates this KeyedState in place so that the given tag maps to the given value.

Method Detail

store

<T> void store(CodedTupleTag<T> tag,
             T value)
           throws java.io.IOException

Updates this KeyedState in place so that the given tag maps to the given value.

Throws:

java.io.IOException - if encoding the given value fails

lookup

<T> T lookup(CodedTupleTag<T> tag)
         throws java.io.IOException

Returns the value associated with the given tag in this KeyedState, or null if the tag has no asssociated value.

See lookup(List) to look up multiple tags at once. It is significantly more efficient to look up multiple tags all at once rather than one at a time.

Throws:

java.io.IOException - if decoding the requested value fails

lookup

CodedTupleTagMap lookup(java.util.List<? extends CodedTupleTag<?>> tags)
                        throws java.io.IOException

Returns a map from the given tags to the values associated with those tags in this KeyedState. A tag will map to null if the tag had no associated value.

See lookup(CodedTupleTag) to look up a single tag.

Throws:

CoderException - if decoding any of the requested values fails

java.io.IOException