org.apache.drill.exec.coord.zk

Class ZkEphemeralStore<V>

java.lang.Object

org.apache.drill.exec.coord.store.BaseTransientStore<V>

org.apache.drill.exec.coord.zk.ZkEphemeralStore<V>

All Implemented Interfaces:

AutoCloseable, TransientStore<V>

public class ZkEphemeralStore<V>
extends BaseTransientStore<V>

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.curator.framework.recipes.cache.PathChildrenCacheListener	dispatcher

Fields inherited from class org.apache.drill.exec.coord.store.BaseTransientStore

config

Constructor Summary

Constructors

Constructor and Description
ZkEphemeralStore(TransientStoreConfig<V> config, org.apache.curator.framework.CuratorFramework curator)

Method Summary

Modifier and Type	Method and Description
void	close()
Iterator<Map.Entry<String,V>>	entries() Returns an iterator of (key, value) tuples.
protected void	fireListeners(TransientStoreEvent event) This method override ensures package level method visibility.
V	get(String key) Returns a value corresponding to the given look-up key if exists, null otherwise.
protected ZookeeperClient	getClient()
V	put(String key, V value) Stores the given (key, value) in this store overriding the existing value.
V	putIfAbsent(String key, V value) Stores the given (key, value) tuple in this store only if it does not exists.
V	remove(String key) Removes the (key, value) tuple from this store if the key exists.
int	size() Returns number of entries.
void	start()

Methods inherited from class org.apache.drill.exec.coord.store.BaseTransientStore

addListener, getConfig, keys, removeListener, values

Methods inherited from class java.lang.Object

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

Field Detail

dispatcher

protected final org.apache.curator.framework.recipes.cache.PathChildrenCacheListener dispatcher

Constructor Detail

ZkEphemeralStore

public ZkEphemeralStore(TransientStoreConfig<V> config,
                        org.apache.curator.framework.CuratorFramework curator)

Method Detail

start

public void start()
           throws Exception

Throws:

Exception

getClient

protected ZookeeperClient getClient()

get

public V get(String key)

Description copied from interface: TransientStore

Returns a value corresponding to the given look-up key if exists, null otherwise.

Parameters:

key - look-up key

put

public V put(String key,
             V value)

Description copied from interface: TransientStore

Stores the given (key, value) in this store overriding the existing value.

Parameters:

key - look-up key

value - value to store

Returns:

the old value if the key exists, null otherwise

putIfAbsent

public V putIfAbsent(String key,
                     V value)

Description copied from interface: TransientStore

Stores the given (key, value) tuple in this store only if it does not exists.

Parameters:

key - look-up key

value - value to store

Returns:

the old value if the key exists, null otherwise

remove

public V remove(String key)

Description copied from interface: TransientStore

Removes the (key, value) tuple from this store if the key exists.

Parameters:

key - look-up key

Returns:

the removed value if key exists, null otherwise

entries

public Iterator<Map.Entry<String,V>> entries()

Description copied from interface: TransientStore

Returns an iterator of (key, value) tuples.

size

public int size()

Description copied from interface: TransientStore

Returns number of entries.

close

public void close()
           throws Exception

Throws:

Exception

fireListeners

protected void fireListeners(TransientStoreEvent event)

This method override ensures package level method visibility.

Overrides:

fireListeners in class BaseTransientStore<V>