Package org.apache.flink.streaming.runtime.tasks

This package contains classes that realize streaming tasks. These tasks are executable stream consumers and producers that are scheduled by the distributed dataflow runtime. Each task occupies one execution slot and is run with by an executing thread.

The tasks merely set up the distributed stream coordination and the checkpointing. Internally, the tasks create one or more operators, perform the stream transformations.

Interface Summary

Interface	Description
ContainingTaskDetails	Details about the operator containing task (such as StreamTask).
OutputWithChainingCheck<OUT>	This is a wrapper for outputs to check whether the collected record has been emitted to a downstream subtask or to a chained operator.
ProcessingTimeService	Defines the current processing time and handles all related actions, such as register timers for tasks to be executed in the future.
ProcessingTimeServiceAware	Interface for StreamOperatorFactory, which enables stream operators to access ProcessingTimeService.
ProcessingTimeServiceFactory	A factory for creating processing time services with a given MailboxExecutor.
StreamTask.CanEmitBatchOfRecordsChecker	Check whether records can be emitted in batch.
StreamTaskActionExecutor	Executes Runnable, ThrowingRunnable, or Callable.
StreamTaskCancellationContext	Context on the StreamTask for figuring out whether it has been cancelled.
SubtaskCheckpointCoordinator	Coordinates checkpointing-related work for a subtask (i.e.
TimerService	A common timer service interface with life cycle methods.
WatermarkGaugeExposingOutput<T>	An Output that measures the last emitted watermark with a WatermarkGauge.

Class Summary

Class	Description
AbstractTwoInputStreamTask<IN1,IN2,OUT>	Abstract class for executing a TwoInputStreamOperator.
FinishedOnRestoreInput<IN>	A fake Input for finished on restore tasks.
FinishedOnRestoreMainOperatorOutput<OUT>	A fake main operator output that skips all the following operators for finished on restored tasks.
FinishedOperatorChain<OUT,OP extends StreamOperator<OUT>>	The OperatorChain that is used for restoring tasks that are TaskStateManager.isTaskDeployedAsFinished().
MultipleInputStreamTask<OUT>	A StreamTask for executing a MultipleInputStreamOperator and supporting the MultipleInputStreamOperator to select input for reading.
OneInputStreamTask<IN,OUT>	A StreamTask for executing a OneInputStreamOperator.
OperatorChain<OUT,OP extends StreamOperator<OUT>>	The OperatorChain contains all operators that are executed as one chain within a single StreamTask.
OperatorChain.ChainedSource	Wrapper class to access the chained sources and their's outputs.
OperatorEventDispatcherImpl	An implementation of the OperatorEventDispatcher.
ProcessingTimeServiceUtil	Utility for classes that implements the ProcessingTimeService interface.
RegularOperatorChain<OUT,OP extends StreamOperator<OUT>>	A regular non finished on restore OperatorChain.
SourceOperatorStreamTask<T>	A subclass of StreamTask for executing the SourceOperator.
SourceOperatorStreamTask.AsyncDataOutputToOutput<T>	Implementation of PushingAsyncDataInput.DataOutput that wraps a specific Output.
SourceStreamTask<OUT,SRC extends SourceFunction<OUT>,OP extends StreamSource<OUT,SRC>>	Deprecated. This class is based on the SourceFunction API, which is due to be removed.
StreamIterationHead<OUT>	A special StreamTask that is used for executing feedback edges.
StreamIterationTail<IN>	A special StreamTask that is used for executing feedback edges.
StreamOperatorWrapper<OUT,OP extends StreamOperator<OUT>>	This class handles the finish, endInput and other related logic of a StreamOperator.
StreamTask<OUT,OP extends StreamOperator<OUT>>	Base class for all streaming tasks.
StreamTaskActionExecutor.SynchronizedStreamTaskActionExecutor	Deprecated. this class should only be used in SourceStreamTask which exposes the checkpoint lock as part of Public API.
StreamTaskFinishedOnRestoreSourceInput<T>	A special source input implementation that immediately emit END_OF_INPUT.
SystemProcessingTimeService	A TimerService which assigns as current processing time the result of calling System.currentTimeMillis() and registers timers using a ScheduledThreadPoolExecutor.
TwoInputStreamTask<IN1,IN2,OUT>	A StreamTask for executing a TwoInputStreamOperator and supporting the TwoInputStreamOperator to select input for reading.

Exception Summary

Exception	Description
ExceptionInChainedOperatorException	A special exception that signifies that the cause exception came from a chained operator.
StreamTaskException	An exception that is thrown by the stream vertices when encountering an illegal condition.
TimerException	RuntimeException for wrapping exceptions that are thrown in the timer callback of the timer service in StreamTask.