Package 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	Description
StreamGraphHasherV2()

Method Summary

Modifier and Type	Method	Description
boolean	generateHashesByStreamNodeId(int streamNodeId, StreamGraph streamGraph, Map<Integer,byte[]> hashes)	Generates a hash for StreamNode with the specified stream node id in the StreamGraph.
static byte[]	generateUserSpecifiedHash(String operatorUid)
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 Transformation.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.

generateUserSpecifiedHash

public static byte[] generateUserSpecifiedHash(String operatorUid)

generateHashesByStreamNodeId

public boolean generateHashesByStreamNodeId(int streamNodeId,
                                            StreamGraph streamGraph,
                                            Map<Integer,byte[]> hashes)

Description copied from interface: StreamGraphHasher

Generates a hash for StreamNode with the specified stream node id in the StreamGraph. This hash is stored in the provided map and can be used to uniquely identify the StreamNode across job submissions, assuming its configuration remains unchanged.

Specified by:

generateHashesByStreamNodeId in interface StreamGraphHasher