org.apache.hadoop.hbase.zookeeper.lock

Class ZKInterProcessReadLock

java.lang.Object

org.apache.hadoop.hbase.zookeeper.lock.ZKInterProcessLockBase

org.apache.hadoop.hbase.zookeeper.lock.ZKInterProcessReadLock

All Implemented Interfaces:

InterProcessLock

@InterfaceAudience.Private
public class ZKInterProcessReadLock
extends ZKInterProcessLockBase

ZooKeeper based read lock: does not exclude other read locks, but excludes and is excluded by write locks.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hbase.zookeeper.lock.ZKInterProcessLockBase

ZKInterProcessLockBase.AcquiredLock, ZKInterProcessLockBase.ZNodeComparator

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.InterProcessLock

InterProcessLock.MetadataHandler

Field Summary

Fields inherited from class org.apache.hadoop.hbase.zookeeper.lock.ZKInterProcessLockBase

acquiredLock, childZNode, fullyQualifiedZNode, handler, metadata, parentLockNode, READ_LOCK_CHILD_NODE_PREFIX, WRITE_LOCK_CHILD_NODE_PREFIX, zkWatcher

Constructor Summary

Constructors

Constructor and Description
ZKInterProcessReadLock(ZooKeeperWatcher zooKeeperWatcher, String znode, byte[] metadata, InterProcessLock.MetadataHandler handler)

Method Summary

Methods

Modifier and Type	Method and Description
protected String	getLockPath(String createdZNode, List<String> children) Determine based on a list of children under a ZNode, whether or not a process which created a specified ZNode has obtained a lock.

Methods inherited from class org.apache.hadoop.hbase.zookeeper.lock.ZKInterProcessLockBase

acquire, handleLockMetadata, handleLockMetadata, isChildOfSameType, isChildReadLock, isChildWriteLock, reapAllLocks, reapExpiredLocks, release, tryAcquire, updateAcquiredLock, visitLocks

Methods inherited from class java.lang.Object

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

Constructor Detail

ZKInterProcessReadLock

public ZKInterProcessReadLock(ZooKeeperWatcher zooKeeperWatcher,
                      String znode,
                      byte[] metadata,
                      InterProcessLock.MetadataHandler handler)

Method Detail

getLockPath

protected String getLockPath(String createdZNode,
                 List<String> children)
                      throws IOException

Determine based on a list of children under a ZNode, whether or not a process which created a specified ZNode has obtained a lock. If a lock is not obtained, return the path that we should watch awaiting its deletion. Otherwise, return null. This method is abstract as the logic for determining whether or not a lock is obtained depends on the type of lock being implemented.

Specified by:

getLockPath in class ZKInterProcessLockBase

Parameters:

createdZNode - The ZNode created by the process attempting to acquire a lock

children - List of all child ZNodes under the lock's parent ZNode

Returns:

The path to watch, or null if myZNode can represent a correctly acquired lock.

Throws:

IOException