org.apache.flink.streaming.api.graph

Class StreamGraphHasherV2

java.lang.Object

org.apache.flink.streaming.api.graph.StreamGraphHasherV2

All Implemented Interfaces:

StreamGraphHasher

public class StreamGraphHasherV2
extends Object
implements StreamGraphHasher

StreamGraphHasher from Flink 1.2. This contains duplicated code to ensure that the algorithm does not change with future Flink versions.

DO NOT MODIFY THIS CLASS

Constructor Summary

Constructors

Constructor and Description
StreamGraphHasherV2()

Method Summary

Modifier and Type	Method and Description
Map<Integer,byte[]>	traverseStreamGraphAndGenerateHashes(StreamGraph streamGraph) Returns a map with a hash for each StreamNode of the StreamGraph.

Methods inherited from class java.lang.Object

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

Constructor Detail

StreamGraphHasherV2

public StreamGraphHasherV2()

Method Detail

traverseStreamGraphAndGenerateHashes

public Map<Integer,byte[]> traverseStreamGraphAndGenerateHashes(StreamGraph streamGraph)

Returns a map with a hash for each StreamNode of the StreamGraph. The hash is used as the JobVertexID in order to identify nodes across job submissions if they didn't change.

The complete StreamGraph is traversed. The hash is either computed from the transformation's user-specified id (see StreamTransformation.getUid()) or generated in a deterministic way.

The generated hash is deterministic with respect to:

• node-local properties (node ID),
• chained output nodes, and
• input nodes hashes

Specified by:

traverseStreamGraphAndGenerateHashes in interface StreamGraphHasher

Returns:

A map from StreamNode.id to hash as 16-byte array.