org.apache.hadoop.hbase
Class MasterAddressTracker

java.lang.Object
  org.apache.hadoop.hbase.zookeeper.ZooKeeperListener
      org.apache.hadoop.hbase.zookeeper.ZooKeeperNodeTracker
          org.apache.hadoop.hbase.MasterAddressTracker

public class MasterAddressTracker
extends ZooKeeperNodeTracker

Manages the location of the current active Master for this RegionServer.

Listens for ZooKeeper events related to the master address. The node /master will contain the address of the current master. This listener is interested in NodeDeleted and NodeCreated events on /master.

Utilizes ZooKeeperNodeTracker for zk interactions.

You can get the current master via getMasterAddress()

Field Summary

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperNodeTracker

abortable, node

Fields inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener

watcher

Constructor Summary

MasterAddressTracker(ZooKeeperWatcher watcher, Abortable abortable)
Construct a master address listener with the specified zookeeper reference.

Method Summary

HServerAddress	getMasterAddress() Get the address of the current master if one is available.
boolean	hasMaster() Check if there is a master available.
HServerAddress	waitForMaster(long timeout) Get the address of the current master.

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperNodeTracker

blockUntilAvailable, blockUntilAvailable, getData, getNode, nodeCreated, nodeDataChanged, nodeDeleted, start, stop

Methods inherited from class org.apache.hadoop.hbase.zookeeper.ZooKeeperListener

nodeChildrenChanged

Methods inherited from class java.lang.Object

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

Constructor Detail

MasterAddressTracker

public MasterAddressTracker(ZooKeeperWatcher watcher,
                            Abortable abortable)

Construct a master address listener with the specified zookeeper reference.

This constructor does not trigger any actions, you must call methods explicitly. Normally you will just want to execute ZooKeeperNodeTracker.start() to begin tracking of the master address.

Parameters:

watcher - zk reference and watcher

abortable - abortable in case of fatal error

Method Detail

getMasterAddress

public HServerAddress getMasterAddress()

Get the address of the current master if one is available. Returns null if no current master.

Returns:

server address of current active master, or null if none available

hasMaster

public boolean hasMaster()

Check if there is a master available.

Returns:

true if there is a master set, false if not.

waitForMaster

public HServerAddress waitForMaster(long timeout)
                             throws java.lang.InterruptedException

Get the address of the current master. If no master is available, method will block until one is available, the thread is interrupted, or timeout has passed.

Parameters:

timeout - maximum time to wait for master in millis, 0 for forever

Returns:

server address of current active master, null if timed out

Throws:

java.lang.InterruptedException - if the thread is interrupted while waiting