[ZOOKEEPER-78] added a high level protocol/feature - for easy Leader Election or exclusive Write Lock creation

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.2.0
• Component/s: java client
• Hadoop Flags: Reviewed
• Assignee: Mahadev Konar
• Reporter: James Strachan
• Created: 17/Jul/08 15:35
• Updated: 08/Jul/09 20:23
• Resolved: 23/Apr/09 21:41

Description

Here's a patch which adds a little WriteLock helper class for performing leader elections or creating exclusive locks in some directory znode. Note its an early cut; am sure we can improve it over time. The aim is to avoid folks having to use the low level ZK stuff but provide a simpler high level abstraction.

Issue Links

• is blocked by: ZOOKEEPER-79 Document jacob's leader election on the wiki recipes page

Sub-Tasks

• implement java.util.concurrent.locks.Lock: Open
• invoke WhenOwnerListener.whenNotOwner() when the ZK connection fails: Closed
• invoke WhenOwnerListener.whenNotOwner() when the ZK session expires and the znode is the leader: Closed
• provide an option for the WriteLock to also watch the locks own znode, so that if someone else deletes it then it is equivalent to calling WriteLock.unlock(): Open
• spring factory beans for ZooKeeper, ZooKeeperFacade and ZooKeeperServer: Open