org.apache.giraph.worker

Class WorkerContext

java.lang.Object

org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable<I,V,E>

org.apache.giraph.worker.WorkerAggregatorDelegator<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.Writable,org.apache.hadoop.io.Writable>

org.apache.giraph.worker.WorkerContext

All Implemented Interfaces:

AggregatorUsage, GiraphConfigurationSettable<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.Writable,org.apache.hadoop.io.Writable>, ImmutableClassesGiraphConfigurable<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.Writable,org.apache.hadoop.io.Writable>, WorkerAggregatorUsage, WorkerBroadcastUsage, WorkerGlobalCommUsage, WorkerIndexUsage<org.apache.hadoop.io.WritableComparable>, WorkerReduceUsage, org.apache.hadoop.io.Writable

Direct Known Subclasses:

BlockWorkerContext, DefaultWorkerContext, PageRankWithKryoSimpleWritable.PageRankWithKryoWorkerContext, RandomMessageBenchmark.RandomMessageBenchmarkWorkerContext, RandomWalkWorkerContext, SimpleCheckpoint.SimpleCheckpointVertexWorkerContext, SimpleMasterComputeComputation.SimpleMasterComputeWorkerContext, SimpleMutateGraphComputation.SimpleMutateGraphVertexWorkerContext, SimplePageRankComputation.SimplePageRankWorkerContext, SimpleVertexWithWorkerContext.EmitterWorkerContext, VerifyMessage.VerifyMessageComputation.VerifyMessageVertexWorkerContext

public abstract class WorkerContext
extends WorkerAggregatorDelegator<org.apache.hadoop.io.WritableComparable,org.apache.hadoop.io.Writable,org.apache.hadoop.io.Writable>
implements org.apache.hadoop.io.Writable, WorkerIndexUsage<org.apache.hadoop.io.WritableComparable>

WorkerContext allows for the execution of user code on a per-worker basis. There's one WorkerContext per worker.

Constructor Summary

Constructors

Constructor and Description
WorkerContext()

Method Summary

Modifier and Type	Method and Description
List<org.apache.hadoop.io.Writable>	getAndClearMessagesFromOtherWorkers() Get messages which other workers sent to this worker and clear them (can be called once per superstep)
org.apache.hadoop.mapreduce.Mapper.Context	getContext() Get the mapper context
int	getMyWorkerIndex() Get index for this worker
long	getSuperstep() Retrieves the current superstep.
long	getTotalNumEdges() Get the total (all workers) number of edges that existed in the previous superstep.
long	getTotalNumVertices() Get the total (all workers) number of vertices that existed in the previous superstep.
int	getWorkerCount() Get number of workers
int	getWorkerForVertex(org.apache.hadoop.io.WritableComparable vertexId) Get worker index which will contain vertex with given id, if such vertex exists.
void	logToCommandLine(String line) Call this to log a line to command line of the job.
abstract void	postApplication() Finalize the WorkerContext.
abstract void	postSuperstep() Execute user code.
abstract void	preApplication() Initialize the WorkerContext.
abstract void	preSuperstep() Execute user code.
void	readFields(DataInput dataInput)
void	sendMessageToWorker(org.apache.hadoop.io.Writable message, int workerIndex) Send message to another worker
void	setGraphState(GraphState graphState) Set the graph state.
void	setupSuperstep(CentralizedServiceWorker<?,?,?> serviceWorker) Setup superstep.
void	write(DataOutput dataOutput)

Methods inherited from class org.apache.giraph.worker.WorkerAggregatorDelegator

aggregate, getAggregatedValue, getBroadcast, reduce, reduceMerge, setWorkerGlobalCommUsage

Methods inherited from class org.apache.giraph.conf.DefaultImmutableClassesGiraphConfigurable

getConf, setConf

Methods inherited from class java.lang.Object

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

Constructor Detail

WorkerContext

public WorkerContext()

Method Detail

setGraphState

public final void setGraphState(GraphState graphState)

Set the graph state.

Parameters:

graphState - Used to set the graph state.

setupSuperstep

public final void setupSuperstep(CentralizedServiceWorker<?,?,?> serviceWorker)

Setup superstep.

Parameters:

serviceWorker - Service worker containing all the information

preApplication

public abstract void preApplication()
                             throws InstantiationException,
                                    IllegalAccessException

Initialize the WorkerContext. This method is executed once on each Worker before the first superstep starts.

Throws:

IllegalAccessException - Thrown for getting the class

InstantiationException - Expected instantiation in this method.

postApplication

public abstract void postApplication()

Finalize the WorkerContext. This method is executed once on each Worker after the last superstep ends.

preSuperstep

public abstract void preSuperstep()

Execute user code. This method is executed once on each Worker before each superstep starts.

getWorkerCount

public final int getWorkerCount()

Get number of workers

Specified by:

getWorkerCount in interface WorkerIndexUsage<org.apache.hadoop.io.WritableComparable>

Returns:

Number of workers

getMyWorkerIndex

public final int getMyWorkerIndex()

Get index for this worker

Specified by:

getMyWorkerIndex in interface WorkerIndexUsage<org.apache.hadoop.io.WritableComparable>

Returns:

Index of this worker

getWorkerForVertex

public final int getWorkerForVertex(org.apache.hadoop.io.WritableComparable vertexId)

Description copied from interface: WorkerIndexUsage

Get worker index which will contain vertex with given id, if such vertex exists.

Specified by:

getWorkerForVertex in interface WorkerIndexUsage<org.apache.hadoop.io.WritableComparable>

Parameters:

vertexId - vertex id

Returns:

worker index

getAndClearMessagesFromOtherWorkers

public final List<org.apache.hadoop.io.Writable> getAndClearMessagesFromOtherWorkers()

Get messages which other workers sent to this worker and clear them (can be called once per superstep)

Returns:

Messages received

sendMessageToWorker

public final void sendMessageToWorker(org.apache.hadoop.io.Writable message,
                                      int workerIndex)

Send message to another worker

Parameters:

message - Message to send

workerIndex - Index of the worker to send the message to

postSuperstep

public abstract void postSuperstep()

Execute user code. This method is executed once on each Worker after each superstep ends.

getSuperstep

public final long getSuperstep()

Retrieves the current superstep.

Returns:

Current superstep

getTotalNumVertices

public final long getTotalNumVertices()

Get the total (all workers) number of vertices that existed in the previous superstep.

Returns:

Total number of vertices (-1 if first superstep)

getTotalNumEdges

public final long getTotalNumEdges()

Get the total (all workers) number of edges that existed in the previous superstep.

Returns:

Total number of edges (-1 if first superstep)

getContext

public final org.apache.hadoop.mapreduce.Mapper.Context getContext()

Get the mapper context

Returns:

Mapper context

logToCommandLine

public final void logToCommandLine(String line)

Call this to log a line to command line of the job. Use in moderation - it's a synchronous call to Job client

Parameters:

line - Line to print

write

public void write(DataOutput dataOutput)
           throws IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

IOException

readFields

public void readFields(DataInput dataInput)
                throws IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

IOException