com.hazelcast.concurrent.lock

Interface LockStore

All Known Implementing Classes:

LockStoreImpl, LockStoreProxy

public interface LockStore

A container for multiple locks. Each lock is differentiated by a different key.

Method Summary

Modifier and Type	Method and Description
boolean	canAcquireLock(Data key, String caller, long threadId) Return if the key can be locked by the caller and thread ID.
boolean	extendLeaseTime(Data key, String caller, long threadId, long leaseTime) Extend the lease time for an already locked key.
boolean	forceUnlock(Data dataKey) Unlock the key regardless of the owner.
int	getLockCount(Data key) Return the number of times a key was locked by the same owner (re-entered).
int	getLockedEntryCount() Return the number of locks this store holds.
Set<Data>	getLockedKeys() Return all locked keys for this store.
String	getOwnerInfo(Data dataKey) Return a string representation of the owner of the lock for a specific key.
long	getRemainingLeaseTime(Data key) Return the remaining lease time for a specific key.
boolean	isLocked(Data key) Check if a key is locked by any caller and thread id.
boolean	isLockedBy(Data key, String caller, long threadId) Check if a key is locked by a specific caller and thread id.
boolean	localLock(Data key, String caller, long threadId, long referenceId, long leaseTime) Lock a specific key on a local partition only.
boolean	lock(Data key, String caller, long threadId, long referenceId, long leaseTime) Lock a specific key.
boolean	shouldBlockReads(Data key) Return whether the reads for the specific key should be blocked (see txnLock(Data, String, long, long, long, boolean)).
boolean	txnLock(Data key, String caller, long threadId, long referenceId, long leaseTime, boolean blockReads) Lock a specific key for use inside a transaction.
boolean	unlock(Data key, String caller, long threadId, long referenceId) Unlock a specific key.

Method Detail

lock

boolean lock(Data key,
             String caller,
             long threadId,
             long referenceId,
             long leaseTime)

Lock a specific key.

Parameters:

key - the key to lock

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

referenceId - the identifier for the invocation of the caller (e.g. operation call ID)

leaseTime - the lease duration in milliseconds

Returns:

if the lock was successfully acquired

localLock

boolean localLock(Data key,
                  String caller,
                  long threadId,
                  long referenceId,
                  long leaseTime)

Lock a specific key on a local partition only. Does not observe LOCK_MAX_LEASE_TIME_SECONDS

Parameters:

key - the key to lock

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

referenceId - the identifier for the invocation of the caller (e.g. operation call ID)

leaseTime - the lease duration in milliseconds

Returns:

if the lock was successfully acquired

See Also:

GroupProperty.LOCK_MAX_LEASE_TIME_SECONDS

txnLock

boolean txnLock(Data key,
                String caller,
                long threadId,
                long referenceId,
                long leaseTime,
                boolean blockReads)

Lock a specific key for use inside a transaction.

Parameters:

key - the key to lock

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

referenceId - the identifier for the invocation of the caller (e.g. operation call ID)

leaseTime - the lease duration in milliseconds

blockReads - whether reads for the key should be blocked (e.g. for map and multimap)

Returns:

if the lock was successfully acquired

extendLeaseTime

boolean extendLeaseTime(Data key,
                        String caller,
                        long threadId,
                        long leaseTime)

Extend the lease time for an already locked key.

Parameters:

key - the locked key

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

leaseTime - time in milliseconds for the lease to be extended

Returns:

if the lease was extended

unlock

boolean unlock(Data key,
               String caller,
               long threadId,
               long referenceId)

Unlock a specific key.

Parameters:

key - the locked key

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

referenceId - the identifier for the invocation of the caller (e.g. operation call ID)

Returns:

if the key was unlocked

isLocked

boolean isLocked(Data key)

Check if a key is locked by any caller and thread id.

Parameters:

key - the key

Returns:

if the key is locked

isLockedBy

boolean isLockedBy(Data key,
                   String caller,
                   long threadId)

Check if a key is locked by a specific caller and thread id.

Parameters:

key - the locked key

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

Returns:

if the key is locked

getLockCount

int getLockCount(Data key)

Return the number of times a key was locked by the same owner (re-entered).

Parameters:

key - the key

Returns:

the reentry count

getLockedEntryCount

int getLockedEntryCount()

Return the number of locks this store holds.

Returns:

the lock count

getRemainingLeaseTime

long getRemainingLeaseTime(Data key)

Return the remaining lease time for a specific key.

Parameters:

key - the key

Returns:

the lease time in milliseconds, -1 if there is no lock, if the key is locked indefinitely

canAcquireLock

boolean canAcquireLock(Data key,
                       String caller,
                       long threadId)

Return if the key can be locked by the caller and thread ID.

Parameters:

key - the locked key

caller - the identifier for the caller

threadId - the identifier for the thread on the caller

Returns:

if the key can be locked. Returns false if the key is already locked by a different caller or thread ID

shouldBlockReads

boolean shouldBlockReads(Data key)

Return whether the reads for the specific key should be blocked (see txnLock(Data, String, long, long, long, boolean)).

Parameters:

key - the lock key

Returns:

if the reads should be blocked

getLockedKeys

Set<Data> getLockedKeys()

Return all locked keys for this store. A lock may be expired when this method returns.

Returns:

all locked keys

forceUnlock

boolean forceUnlock(Data dataKey)

Unlock the key regardless of the owner. May return true if the key is already unlocked but has waiters/signals/expired operations.

Parameters:

dataKey - the lock key

Returns:

if the key was unlocked or is already unlocked

getOwnerInfo

String getOwnerInfo(Data dataKey)

Return a string representation of the owner of the lock for a specific key. If the key is not locked returns a default string depicting no owner.

Parameters:

dataKey - the key

Returns:

a string description/representation of the owner