org.apache.flink.streaming.runtime.tasks

Class SourceStreamTask<OUT>

java.lang.Object

org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

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

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

Type Parameters:

OUT - Type of the output elements of this source.

All Implemented Interfaces:

StatefulTask<StreamTaskStateList>

public class SourceStreamTask<OUT>
extends StreamTask<OUT,StreamSource<OUT>>

Task for executing streaming sources. One important aspect of this is that the checkpointing and the emission of elements must never occur at the same time. The execution must be serial. This is achieved by having the contract with the StreamFunction that it must only modify its state or emit elements in a synchronized block that locks on the lock Object. Also, the modification of the state and the emission of elements must happen in the same block of code that is protected by the synchronized block.

Field Summary

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

headOperator, LOG, TRIGGER_THREAD_GROUP

Constructor Summary

Constructors

Constructor and Description
SourceStreamTask()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	cancelTask()
protected void	cleanup()
protected void	init()
protected void	run()

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

cancel, checkTimerException, finalize, getAccumulatorMap, getCheckpointBarrierListener, getCheckpointLock, getConfiguration, getHeadOutput, getName, getStateBackend, getStreamOutputs, invoke, notifyCheckpointComplete, registerInputOutput, registerTimer, restoreStateLazy, setInitialState, toString, triggerCheckpoint

Methods inherited from class org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

getCurrentNumberOfSubtasks, getEnvironment, getExecutionConfig, getIndexInSubtaskGroup, getJobConfiguration, getTaskConfiguration, getUserCodeClassLoader, setEnvironment

Methods inherited from class java.lang.Object

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

Constructor Detail

SourceStreamTask

public SourceStreamTask()

Method Detail

init

protected void init()

Specified by:

init in class StreamTask<OUT,StreamSource<OUT>>

cleanup

protected void cleanup()

Specified by:

cleanup in class StreamTask<OUT,StreamSource<OUT>>

run

protected void run()
            throws Exception

Specified by:

run in class StreamTask<OUT,StreamSource<OUT>>

Throws:

Exception

cancelTask

protected void cancelTask()
                   throws Exception

Specified by:

cancelTask in class StreamTask<OUT,StreamSource<OUT>>

Throws:

Exception