org.apache.flink.runtime.io.network.api

Class CheckpointBarrier

java.lang.Object

org.apache.flink.runtime.event.AbstractEvent

org.apache.flink.runtime.event.RuntimeEvent

org.apache.flink.runtime.io.network.api.CheckpointBarrier

All Implemented Interfaces:

IOReadableWritable

public class CheckpointBarrier
extends RuntimeEvent

Checkpoint barriers are used to align checkpoints throughout the streaming topology. The barriers are emitted by the sources when instructed to do so by the JobManager. When operators receive a CheckpointBarrier on one of its inputs, it knows that this is the point between the pre-checkpoint and post-checkpoint data.

Once an operator has received a checkpoint barrier from all its input channels, it knows that a certain checkpoint is complete. It can trigger the operator specific checkpoint behavior and broadcast the barrier to downstream operators.

Depending on the semantic guarantees, may hold off post-checkpoint data until the checkpoint is complete (exactly once)

The checkpoint barrier IDs are strictly monotonous increasing.

Constructor Summary

Constructors

Constructor and Description
CheckpointBarrier()
CheckpointBarrier(long id, long timestamp)

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object other)
long	getId()
long	getTimestamp()
int	hashCode()
void	read(DataInputView in) Reads the object's internal data from the given data input view.
String	toString()
void	write(DataOutputView out) Writes the object's internal data to the given data output view.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CheckpointBarrier

public CheckpointBarrier()

CheckpointBarrier

public CheckpointBarrier(long id,
                         long timestamp)

Method Detail

getId

public long getId()

getTimestamp

public long getTimestamp()

write

public void write(DataOutputView out)
           throws IOException

Description copied from interface: IOReadableWritable

Writes the object's internal data to the given data output view.

Parameters:

out - the output view to receive the data.

Throws:

IOException - thrown if any error occurs while writing to the output stream

read

public void read(DataInputView in)
          throws IOException

Description copied from interface: IOReadableWritable

Reads the object's internal data from the given data input view.

Parameters:

in - the input view to read the data from

Throws:

IOException - thrown if any error occurs while reading from the input stream

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object