org.adroitlogic.x.clustering

Class CommandProcessor

java.lang.Object

org.adroitlogic.x.clustering.CommandProcessor

All Implemented Interfaces:

Startable, org.apache.curator.framework.recipes.cache.PathChildrenCacheListener

public class CommandProcessor
extends Object
implements Startable, org.apache.curator.framework.recipes.cache.PathChildrenCacheListener

Command processor of the new cluster manager implementation. This class make use of the curator recipe, PathChildrenCache to watch on a particular node and ensure that it receives all the events.

Since:

17.01

Author:

Imesha Sudasingha

Constructor Summary

Constructors

Constructor and Description
CommandProcessor(org.apache.curator.framework.CuratorFramework client, ClusterPaths clusterPaths) Constructor of CommandProcessor.

Method Summary

Modifier and Type	Method and Description
void	childEvent(org.apache.curator.framework.CuratorFramework client, org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent event)
(package private) org.apache.curator.framework.recipes.cache.ChildData	getArchivedCommand(int version) Get the command corresponding to a specific command version.
(package private) org.apache.curator.framework.recipes.cache.ChildData	getCommand(int version) Get the command corresponding to a specific command version.
(package private) Map<Integer,org.apache.curator.framework.recipes.cache.ChildData>	getCommands(int from, int to) Fetches the commands from a given zookeeper cluster version to another.
String	getCommandsZNodePath()
(package private) int	getCommandVersion()
(package private) void	retryCommand(int commandVersion) Retries a given command.
(package private) void	setCommandVersion(int commandVersion) Since zookeeper ZNode's CVersion(Child version) are 1-based and the sequential path sequence numbers are 0-based, there's always a difference of 1 unit between the
void	start()
void	stop()

Methods inherited from class java.lang.Object

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

Constructor Detail

CommandProcessor

public CommandProcessor(org.apache.curator.framework.CuratorFramework client,
                        ClusterPaths clusterPaths)

Constructor of CommandProcessor. This will create a PathChildrenCache instance to be used throughout the lifetime of the command processor to get the events related to commands ZNodes. The PathChildrenCache will use a single thread to process events in this implementation.

Parameters:

client - CuratorFramework instance being used by the cluster manager

clusterPaths - ClusterPaths instance used by the cluster manager

Method Detail

start

public void start()

Specified by:

start in interface Startable

stop

public void stop()

Specified by:

stop in interface Startable

childEvent

public void childEvent(org.apache.curator.framework.CuratorFramework client,
                       org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent event)
                throws Exception

Specified by:

childEvent in interface org.apache.curator.framework.recipes.cache.PathChildrenCacheListener

Throws:

Exception

getCommands

Map<Integer,org.apache.curator.framework.recipes.cache.ChildData> getCommands(int from,
                                                                              int to)

Fetches the commands from a given zookeeper cluster version to another.

Parameters:

from - starting version number

to - ending version number

Returns:

commands map

getCommand

org.apache.curator.framework.recipes.cache.ChildData getCommand(int version)
                                                         throws Exception

Get the command corresponding to a specific command version.

Parameters:

version - CVersion (child version) of the expected command

Returns:

ChildData | null

Throws:

Exception - zookeeper errors

getArchivedCommand

org.apache.curator.framework.recipes.cache.ChildData getArchivedCommand(int version)
                                                                 throws Exception

Get the command corresponding to a specific command version.

Parameters:

version - CVersion (child version) of the expected command

Returns:

ChildData | null

Throws:

Exception - zookeeper errors

retryCommand

void retryCommand(int commandVersion)

Retries a given command. A command is identified by its command version

Parameters:

commandVersion - command version to be retried

See Also:

CuratorClusterManager.retryCommand(int)

setCommandVersion

void setCommandVersion(int commandVersion)

Since zookeeper ZNode's CVersion(Child version) are 1-based and the sequential path sequence numbers are 0-based, there's always a difference of 1 unit between the

commands/current

node's CVersion and the CommandProcessor's

commandVersion

Parameters:

commandVersion - the command version to be set.

getCommandsZNodePath

public String getCommandsZNodePath()

getCommandVersion

int getCommandVersion()

Returns:

Current command version of this node

See Also:

setCommandVersion(int)