org.apache.accumulo.fate.zookeeper

Class ZooCache

java.lang.Object

org.apache.accumulo.fate.zookeeper.ZooCache

public class ZooCache
extends Object

A cache for values stored in ZooKeeper. Values are kept up to date as they change.

Constructor Summary

Constructors

Constructor and Description
ZooCache(String zooKeepers, int sessionTimeout) Creates a new cache.
ZooCache(String zooKeepers, int sessionTimeout, org.apache.zookeeper.Watcher watcher) Creates a new cache.
ZooCache(ZooReader reader, org.apache.zookeeper.Watcher watcher) Creates a new cache.

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Clears this cache.
void	clear(String zPath) Clears this cache of all information about nodes rooted at the given path.
protected void	copyStats(org.apache.zookeeper.data.Stat userStat, org.apache.zookeeper.data.Stat cachedStat) Helper method to copy stats from the cached stat into userStat
byte[]	get(String zPath) Gets data at the given path.
byte[]	get(String zPath, org.apache.zookeeper.data.Stat status) Gets data at the given path, filling status information into the given Stat object.
List<String>	getChildren(String zPath) Gets the children of the given node.
static ZooCache	getInstance(String zooKeepers, int sessionTimeout) Deprecated. Use ZooCacheFactory instead.

Methods inherited from class java.lang.Object

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

Constructor Detail

ZooCache

public ZooCache(String zooKeepers,
        int sessionTimeout)

Creates a new cache.

Parameters:

zooKeepers - comma-separated list of ZooKeeper host[:port]s

sessionTimeout - ZooKeeper session timeout

ZooCache

public ZooCache(String zooKeepers,
        int sessionTimeout,
        org.apache.zookeeper.Watcher watcher)

Creates a new cache. The given watcher is called whenever a watched node changes.

Parameters:

zooKeepers - comma-separated list of ZooKeeper host[:port]s

sessionTimeout - ZooKeeper session timeout

watcher - watcher object

ZooCache

public ZooCache(ZooReader reader,
        org.apache.zookeeper.Watcher watcher)

Creates a new cache. The given watcher is called whenever a watched node changes.

Parameters:

reader - ZooKeeper reader

watcher - watcher object

Method Detail

getChildren

public List<String> getChildren(String zPath)

Gets the children of the given node. A watch is established by this call.

Parameters:

zPath - path of node

Returns:

children list, or null if node has no children or does not exist

get

public byte[] get(String zPath)

Gets data at the given path. Status information is not returned. A watch is established by this call.

Parameters:

zPath - path to get

Returns:

path data, or null if non-existent

get

public byte[] get(String zPath,
         org.apache.zookeeper.data.Stat status)

Gets data at the given path, filling status information into the given Stat object. A watch is established by this call.

Parameters:

zPath - path to get

status - status object to populate

Returns:

path data, or null if non-existent

copyStats

protected void copyStats(org.apache.zookeeper.data.Stat userStat,
             org.apache.zookeeper.data.Stat cachedStat)

Helper method to copy stats from the cached stat into userStat

Parameters:

userStat - user Stat object

cachedStat - cached statistic, that is or will be cached

clear

public void clear()

Clears this cache.

clear

public void clear(String zPath)

Clears this cache of all information about nodes rooted at the given path.

Parameters:

zPath - path of top node

getInstance

@Deprecated
public static ZooCache getInstance(String zooKeepers,
                              int sessionTimeout)

Deprecated. Use ZooCacheFactory instead.