Package com.github.ddth.dlock

Interface IDLock

All Known Implementing Classes:

AbstractDLock, BaseRedisDLock, ClusteredRedisDLock, InmemDLock, RedisDLock

public interface IDLock

Distributed lock interface.

Implementation:

• Each lock is identified by a unique name(space).
• Within a name(space), only one client is allowed to hold lock as a given time; each client is identified by a unique client-id (within the namespace).

Since:

0.1.0

Author:

Thanh Nguyen

Field Summary

Fields

Modifier and Type	Field	Description
static long	DEFAULT_LOCK_DURATION_MS

Method Summary

Modifier and Type	Method	Description
String	getName()	Get lock's name(space).
LockResult	lock(int waitWeight, String clientId)	Acquire the lock for clientId with default duration.
LockResult	lock(int waitWeight, String clientId, long lockDurationMs)	Acquire the lock for clientId for a duration of lockDurationMs.
LockResult	lock(String clientId)	Acquire the lock for clientId with default duration.
LockResult	lock(String clientId, long lockDurationMs)	Acquire the lock for clientId for a duration of lockDurationMs.
LockResult	unlock(String clientId)	Release the lock.

Field Detail

DEFAULT_LOCK_DURATION_MS

static final long DEFAULT_LOCK_DURATION_MS

See Also:

Constant Field Values

Method Detail

getName

String getName()

Get lock's name(space).

Returns:

lock

LockResult lock(String clientId)
         throws DLockException

Acquire the lock for clientId with default duration.

Reentrant: lock can be acquired multiple times by the same clientId. Lock's expiry will be extended accordingly.

Parameters:

clientId - within a namespace, only one client is allowed to hold lock as a given time

Returns:

LockResult.SUCCESSFUL if successful, LockResult.HOLD_BY_ANOTHER_CLIENT if lock is currently hold by another client

Throws:

DLockException

lock

LockResult lock(String clientId,
                long lockDurationMs)

Acquire the lock for clientId for a duration of lockDurationMs.

Reentrant: lock can be acquired multiple times by the same clientId. Lock's expiry will be extended accordingly.

Parameters:

clientId - within a namespace, only one client is allowed to hold the lock as a given time

lockDurationMs -

Returns:

LockResult.SUCCESSFUL if successful, LockResult.HOLD_BY_ANOTHER_CLIENT if lock is currently hold by another client

lock

LockResult lock(int waitWeight,
                String clientId)

Acquire the lock for clientId with default duration.

Reentrant: lock can be acquired multiple times by the same clientId. Lock's expiry will be extended accordingly.

Parameters:

waitWeight - "fairness": clientId with higher waitWeight value might have higher chance to acquire the lock, negative value means "no fairness"

clientId - within a namespace, only one client is allowed to hold the lock as a given time

Returns:

LockResult.SUCCESSFUL if successful, LockResult.HOLD_BY_ANOTHER_CLIENT if lock is currently hold by another client

Since:

0.1.2

lock

LockResult lock(int waitWeight,
                String clientId,
                long lockDurationMs)

Acquire the lock for clientId for a duration of lockDurationMs.

Reentrant: lock can be acquired multiple times by the same clientId. Lock's expiry will be extended accordingly.

Parameters:

waitWeight - "fairness": clientId with higher waitWeight value might have higher chance to acquire the lock, negative value means "no fairness"

clientId - within a namespace, only one client is allowed to hold the lock as a given time

lockDurationMs -

Returns:

LockResult.SUCCESSFUL if successful, LockResult.HOLD_BY_ANOTHER_CLIENT if lock is currently hold by another client

Since:

0.1.2

unlock

LockResult unlock(String clientId)

Release the lock.

Parameters:

clientId - within a namespace, only one client is allowed to hold the lock as a given time

Returns:

LockResult.SUCCESSFUL if successful, LockResult.HOLD_BY_ANOTHER_CLIENT if lock is currently hold by another client, LockResult.NOT_FOUND if the lock is not currently hold by any client (not locked before, or already expired)