org.apache.beam.sdk.io

Class CountingSource.CounterMark

java.lang.Object

org.apache.beam.sdk.io.CountingSource.CounterMark

All Implemented Interfaces:

UnboundedSource.CheckpointMark

Enclosing class:

CountingSource

@DefaultCoder(value=CountingSource.CounterMarkCoder.class)
public static class CountingSource.CounterMark
extends java.lang.Object
implements UnboundedSource.CheckpointMark

The checkpoint for an unbounded CountingSource is simply the last value produced. The associated source object encapsulates the information needed to produce the next value.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.beam.sdk.io.UnboundedSource.CheckpointMark

UnboundedSource.CheckpointMark.NoopCheckpointMark

Field Summary

Fields inherited from interface org.apache.beam.sdk.io.UnboundedSource.CheckpointMark

NOOP_CHECKPOINT_MARK

Constructor Summary

Constructors

Constructor and Description
CounterMark(long lastEmitted, Instant startTime) Creates a checkpoint mark reflecting the last emitted value.

Method Summary

Modifier and Type	Method and Description
void	finalizeCheckpoint() Called by the system to signal that this checkpoint mark has been committed along with all the records which have been read from the UnboundedSource.UnboundedReader since the previous checkpoint was taken.
long	getLastEmitted() Returns the last value emitted by the reader.
Instant	getStartTime() Returns the time the reader was started.

Methods inherited from class java.lang.Object

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

Constructor Detail

CounterMark

public CounterMark(long lastEmitted,
                   Instant startTime)

Creates a checkpoint mark reflecting the last emitted value.

Method Detail

getLastEmitted

public long getLastEmitted()

Returns the last value emitted by the reader.

getStartTime

public Instant getStartTime()

Returns the time the reader was started.

finalizeCheckpoint

public void finalizeCheckpoint()
                        throws java.io.IOException

Description copied from interface: UnboundedSource.CheckpointMark

Called by the system to signal that this checkpoint mark has been committed along with all the records which have been read from the UnboundedSource.UnboundedReader since the previous checkpoint was taken.

For example, this method could send acknowledgements to an external data source such as Pubsub.

Note that:

• This finalize method may be called from any thread, concurrently with calls to the UnboundedSource.UnboundedReader it was created from.
• Checkpoints will not necessarily be finalized as soon as they are created. A checkpoint may be taken while a previous checkpoint from the same UnboundedSource.UnboundedReader has not yet be finalized.
• In the absence of failures, all checkpoints will be finalized and they will be finalized in the same order they were taken from the UnboundedSource.UnboundedReader.
• It is possible for a checkpoint to be taken but this method never called. This method will never be called if the checkpoint could not be committed, and other failures may cause this method to never be called.
• It is not safe to assume the UnboundedSource.UnboundedReader from which this checkpoint was created still exists at the time this method is called.

Specified by:

finalizeCheckpoint in interface UnboundedSource.CheckpointMark

Throws:

java.io.IOException