org.lable.oss.dynamicconfig.zookeeper

Class MonitoringZookeeperConnection

java.lang.Object

org.lable.oss.dynamicconfig.zookeeper.MonitoringZookeeperConnection

All Implemented Interfaces:

Closeable, AutoCloseable

public class MonitoringZookeeperConnection
extends Object
implements Closeable

Connects to a ZooKeeper quorum and watches a number of nodes for changes.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	MonitoringZookeeperConnection.NodeChangeListener
static class	MonitoringZookeeperConnection.State State of the MonitoringZookeeperConnection class.

Constructor Summary

Constructors

Constructor and Description
MonitoringZookeeperConnection(String quorum)
MonitoringZookeeperConnection(String[] quorum)
MonitoringZookeeperConnection(String[] quorum, String chroot, MonitoringZookeeperConnection.NodeChangeListener changeListener) Create a new MonitoringZookeeperConnection.

Method Summary

Modifier and Type	Method and Description
void	close()
void	deregisterObserver(ZooKeeperConnectionObserver observer)
org.apache.zookeeper.ZooKeeper	getActiveConnection()
MonitoringZookeeperConnection.State	getState() Get the current state of the connection to the ZooKeeper quorum.
void	listen(String node) Start watching a node for changes.
void	listen(String node, boolean loadInitially) Start watching a node for changes.
Optional<InputStream>	load(String node) Attempt to retrieve the contents of a ZooKeeper node.
ZooKeeperLock	prepareLock(String znode)
void	registerObserver(ZooKeeperConnectionObserver observer)
void	set(String node, String value, boolean createIfMissing)
void	stopListening(String part)

Methods inherited from class java.lang.Object

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

Constructor Detail

MonitoringZookeeperConnection

public MonitoringZookeeperConnection(String quorum)

MonitoringZookeeperConnection

public MonitoringZookeeperConnection(String[] quorum)

MonitoringZookeeperConnection

public MonitoringZookeeperConnection(String[] quorum,
                                     String chroot,
                                     MonitoringZookeeperConnection.NodeChangeListener changeListener)

Create a new MonitoringZookeeperConnection.

Parameters:

quorum - ZooKeeper quorum addresses.

chroot - Optional; limit the ZooKeeper connection to this prefix.

changeListener - Callback interface called when a node changes.

Method Detail

load

public Optional<InputStream> load(String node)

Attempt to retrieve the contents of a ZooKeeper node.

Parameters:

node - The name of the node. If this class was constructed with a chroot, then the node is relative to that chroot.

Returns:

An optional containing the data as an InputStream, or empty if the node was not found.

set

public void set(String node,
                String value,
                boolean createIfMissing)

registerObserver

public void registerObserver(ZooKeeperConnectionObserver observer)

deregisterObserver

public void deregisterObserver(ZooKeeperConnectionObserver observer)

getState

public MonitoringZookeeperConnection.State getState()

Get the current state of the connection to the ZooKeeper quorum.

Returns:

The connection state.

getActiveConnection

public org.apache.zookeeper.ZooKeeper getActiveConnection()

listen

public void listen(String node)

Start watching a node for changes. When a change occurs, the MonitoringZookeeperConnection.NodeChangeListener passed to this class during construction will be called.

Parameters:

node - The name of the node. If this class was constructed with a chroot, then the node is relative to that chroot.

listen

public void listen(String node,
                   boolean loadInitially)

Start watching a node for changes. When a change occurs, the MonitoringZookeeperConnection.NodeChangeListener passed to this class during construction will be called.

Parameters:

node - The name of the node. If this class was constructed with a chroot, then the node is relative to that chroot.

loadInitially - If true, the callback listener will be called with the current contents of the node. If false, the callback won't be triggered until the node changes.

stopListening

public void stopListening(String part)

prepareLock

public ZooKeeperLock prepareLock(String znode)

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException