org.apache.flink.streaming.runtime.tasks

Class StreamIterationHead<OUT>

java.lang.Object

org.apache.flink.streaming.runtime.tasks.StreamTask<OUT,OneInputStreamOperator<IN,OUT>>

org.apache.flink.streaming.runtime.tasks.OneInputStreamTask<OUT,OUT>

org.apache.flink.streaming.runtime.tasks.StreamIterationHead<OUT>

All Implemented Interfaces:

CheckpointableTask, CoordinatedTask, TaskInvokable, AsyncExceptionHandler, ContainingTaskDetails

@Internal
public class StreamIterationHead<OUT>
extends OneInputStreamTask<OUT,OUT>

A special StreamTask that is used for executing feedback edges. This is used in combination with StreamIterationTail.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.streaming.runtime.tasks.StreamTask

StreamTask.CanEmitBatchOfRecordsChecker

Field Summary

Fields inherited from class org.apache.flink.streaming.runtime.tasks.StreamTask

checkpointStorage, configuration, inputProcessor, mailboxProcessor, mainOperator, operatorChain, recordWriter, stateBackend, systemTimerService, timerService, TRIGGER_THREAD_GROUP

Constructor Summary

Constructors

Constructor and Description
StreamIterationHead(Environment env)

Method Summary

Modifier and Type	Method and Description
protected void	cleanUpInternal()
static String	createBrokerIdString(JobID jid, String iterationID, int subtaskIndex) Creates the identification string with which head and tail task find the shared blocking queue for the back channel.
void	init()
protected void	processInput(MailboxDefaultAction.Controller controller) This method implements the default action of the task (e.g.

Methods inherited from class org.apache.flink.streaming.runtime.tasks.OneInputStreamTask

getCheckpointBarrierHandler

Methods inherited from class org.apache.flink.streaming.runtime.tasks.StreamTask

abortCheckpointOnBarrier, advanceToEndOfEventTime, afterInvoke, cancel, cancelTask, cleanUp, createRecordWriterDelegate, createStreamTaskStateInitializer, declineCheckpoint, dispatchOperatorEvent, endData, finalize, getAsyncCheckpointStartDelayNanos, getAsyncOperationsThreadPool, getCancelables, getCanEmitBatchOfRecords, getCheckpointStorage, getCompletionFuture, getConfiguration, getEnvironment, getMailboxExecutorFactory, getName, getProcessingTimeServiceFactory, handleAsyncException, invoke, isCanceled, isFailing, isMailboxLoopRunning, isRunning, isUsingNonBlockingInput, maybeInterruptOnCancel, notifyCheckpointAbortAsync, notifyCheckpointCompleteAsync, notifyCheckpointSubsumedAsync, restore, runMailboxLoop, runMailboxStep, setSynchronousSavepoint, setupNumRecordsInCounter, toString, triggerCheckpointAsync, triggerCheckpointOnBarrier

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.streaming.runtime.tasks.ContainingTaskDetails

getExecutionConfig, getIndexInSubtaskGroup, getJobConfiguration, getUserCodeClassLoader

Constructor Detail

StreamIterationHead

public StreamIterationHead(Environment env)
                    throws Exception

Throws:

Exception

Method Detail

processInput

protected void processInput(MailboxDefaultAction.Controller controller)
                     throws Exception

Description copied from class: StreamTask

This method implements the default action of the task (e.g. processing one event from the input). Implementations should (in general) be non-blocking.

Overrides:

processInput in class StreamTask<OUT,OneInputStreamOperator<OUT,OUT>>

Parameters:

controller - controller object for collaborative interaction between the action and the stream task.

Throws:

Exception - on any problems in the action.

init

public void init()

Overrides:

init in class OneInputStreamTask<OUT,OUT>

cleanUpInternal

protected void cleanUpInternal()

Overrides:

cleanUpInternal in class StreamTask<OUT,OneInputStreamOperator<OUT,OUT>>

createBrokerIdString

public static String createBrokerIdString(JobID jid,
                                          String iterationID,
                                          int subtaskIndex)

Creates the identification string with which head and tail task find the shared blocking queue for the back channel. The identification string is unique per parallel head/tail pair per iteration per job.

Parameters:

jid - The job ID.

iterationID - The id of the iteration in the job.

subtaskIndex - The parallel subtask number

Returns:

The identification string.