Package org.apache.solr.cloud

Interface DistributedCollectionLockFactory

All Known Implementing Classes:

ZkDistributedCollectionLockFactory

public interface DistributedCollectionLockFactory

Method Summary

Modifier and Type	Method	Description
DistributedLock	createLock(boolean isWriteLock, CollectionParams.LockLevel level, String collName, String shardId, String replicaName)	Create a new lock of the specified type (read or write) entering the "competition" for actually getting the lock at the given level for the given path i.e.

Method Detail

createLock

DistributedLock createLock(boolean isWriteLock,
                           CollectionParams.LockLevel level,
                           String collName,
                           String shardId,
                           String replicaName)

Create a new lock of the specified type (read or write) entering the "competition" for actually getting the lock at the given level for the given path i.e. a lock at collName or a lock at collName/shardId or a lock at collName/shardId/replicaName, depending on the passed level.

The paths are used to define which locks compete with each other (locks of equal paths compete).

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).

Parameters:

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

level - The requested locking level. Can be one of:

• CollectionParams.LockLevel.COLLECTION
• CollectionParams.LockLevel.SHARD
• CollectionParams.LockLevel.REPLICA

collName - the collection name, can never be null as is needed for all locks.

shardId - is ignored and can be null if level is CollectionParams.LockLevel.COLLECTION

replicaName - is ignored and can be null if level is CollectionParams.LockLevel.COLLECTION or CollectionParams.LockLevel.SHARD

Returns:

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