Package org.apache.solr.cloud

Class ZkDistributedConfigSetLockFactory

java.lang.Object

org.apache.solr.cloud.ZkDistributedConfigSetLockFactory

All Implemented Interfaces:

DistributedConfigSetLockFactory

public class ZkDistributedConfigSetLockFactory
extends Object
implements DistributedConfigSetLockFactory

A distributed lock implementation using Zookeeper "directory" nodes created within a collection znode hierarchy, for use with the distributed Collection API implementation. The locks are implemented using ephemeral nodes placed below the "directory" nodes.

See Also:

Zookeeper lock recipe

Constructor Summary

Constructors

Constructor	Description
ZkDistributedConfigSetLockFactory(org.apache.solr.common.cloud.SolrZkClient zkClient, String rootPath)

Method Summary

Modifier and Type	Method	Description
DistributedLock	createLock(boolean isWriteLock, String configSetName)	Create a new lock of the specified type (read or write) entering the "competition" for actually getting the lock for the configSetName
protected DistributedLock	doCreateLock(boolean isWriteLock, String lockPath)
protected StringBuilder	getPathPrefix()

Methods inherited from class java.lang.Object

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

Constructor Detail

ZkDistributedConfigSetLockFactory

public ZkDistributedConfigSetLockFactory(org.apache.solr.common.cloud.SolrZkClient zkClient,
                                         String rootPath)

Method Detail

createLock

public DistributedLock createLock(boolean isWriteLock,
                                  String configSetName)

Description copied from interface: DistributedConfigSetLockFactory

Create a new lock of the specified type (read or write) entering the "competition" for actually getting the lock for the configSetName

Upon return from this call, the lock has not been acquired but the it had entered the lock acquiring "competition", and the caller can decide to wait until the lock is granted by calling DistributedLock.waitUntilAcquired().
Separating the lock creation from lock acquisition allows a more deterministic release of the locks when/if they can't be acquired.

Locks at different paths are independent of each other, multiple DistributedLock are therefore requested for a single operation and are packaged together and returned as an DistributedMultiLock, see CollectionApiLockFactory.createCollectionApiLock(org.apache.solr.common.params.CollectionParams.LockLevel, java.lang.String, java.lang.String, java.lang.String) or ConfigSetApiLockFactory.createConfigSetApiLock(java.lang.String, java.lang.String).

Specified by:

createLock in interface DistributedConfigSetLockFactory

Parameters:

isWriteLock - true if requesting a write lock, false for a read lock.

configSetName - the config set name, can never be null.

Returns:

a lock instance that must be DistributedLock.release()'ed in a finally, regardless of the lock having been acquired or not.

doCreateLock

protected DistributedLock doCreateLock(boolean isWriteLock,
                                       String lockPath)

getPathPrefix

protected StringBuilder getPathPrefix()