software.amazon.kinesis.coordinator.migration

Class ClientVersionChangeMonitor

java.lang.Object

software.amazon.kinesis.coordinator.migration.ClientVersionChangeMonitor

All Implemented Interfaces:

Runnable

@ThreadSafe
public class ClientVersionChangeMonitor
extends Object
implements Runnable

Change monitor for MigrationState.clientVersion to notify a callback if the value changes from a given value. This monitor will be run to monitor rollback, roll-forward and also upgrade to 3.x scenarios. Look at ClientVersion for more details. Since all KCL workers will be running the monitor, the monitor poll interval uses a random jitter to stagger the reads to ddb. The class is thread-safe and will invoke callback on a separate thread.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ClientVersionChangeMonitor.ClientVersionChangeCallback Interface of a callback to invoke when monitor condition is true.

Constructor Summary

Constructors

Constructor and Description
ClientVersionChangeMonitor()

Method Summary

Modifier and Type	Method and Description
void	cancel() Cancel the monitor explicity before the condition is met, e.g.
void	run()
void	startMonitor()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ClientVersionChangeMonitor

public ClientVersionChangeMonitor()

Method Detail

startMonitor

public void startMonitor()

toString

public String toString()

Overrides:

toString in class Object

cancel

public void cancel()

Cancel the monitor explicity before the condition is met, e.g. when the worker is going down. Note on synchronization: callback of this monitor is invoked while holding the lock on this monitor object. If cancel is called from within the same lock context that callback uses, then it can lead to deadlock. Ensure synchronization context between callback the caller of cancel is not shared.

run

public void run()

Specified by:

run in interface Runnable