com.sleepycat.je.txn
Interface Lock

All Known Implementing Classes:

LockImpl, ThinLockImpl

interface Lock

A Lock embodies the lock state of a NodeId. It includes a set of owners and a list of waiters.

Method Summary

void	demote(Locker locker) Downgrade a write lock to a read lock.
void	flushWaiter(Locker locker, MemoryBudget mb, int lockTableIndex) Remove this locker from the waiter list.
java.util.Set<LockInfo>	getOwnersClone() Get a new Set of the owners.
java.util.List<LockInfo>	getWaitersListClone() Get a list of waiters for debugging and error messages.
Locker	getWriteOwnerLocker() Return the locker that has a write ownership on this lock.
boolean	isOwnedWriteLock(Locker locker) Return true if locker is an owner of this Lock and this is a write lock.
boolean	isOwner(Locker locker, LockType lockType) Return true if locker is an owner of this Lock for lockType, false otherwise.
boolean	isThin()
boolean	isWaiter(Locker locker) Return true if locker is a waiter on this Lock.
LockAttemptResult	lock(LockType requestType, Locker locker, boolean nonBlockingRequest, MemoryBudget mb, int lockTableIndex) Attempts to acquire the lock and returns the LockGrantType.
int	nOwners()
int	nWaiters()
java.util.Set<Locker>	release(Locker locker, MemoryBudget mb, int lockTableIndex) Releases a lock and moves the next waiter(s) to the owners.
java.lang.String	toString() Debug dumper.
Lock	transfer(java.lang.Long nodeId, Locker currentLocker, Locker destLocker, MemoryBudget mb, int lockTableIndex) Transfer a lock from one transaction to another.
Lock	transferMultiple(java.lang.Long nodeId, Locker currentLocker, Locker[] destLockers, MemoryBudget mb, int lockTableIndex) Transfer a lock from one transaction to many others.

Method Detail

getWaitersListClone

java.util.List<LockInfo> getWaitersListClone()

Get a list of waiters for debugging and error messages.

flushWaiter

void flushWaiter(Locker locker,
                 MemoryBudget mb,
                 int lockTableIndex)

Remove this locker from the waiter list.

getOwnersClone

java.util.Set<LockInfo> getOwnersClone()

Get a new Set of the owners.

isOwner

boolean isOwner(Locker locker,
                LockType lockType)

Return true if locker is an owner of this Lock for lockType, false otherwise. This method is only used by unit tests.

isOwnedWriteLock

boolean isOwnedWriteLock(Locker locker)

Return true if locker is an owner of this Lock and this is a write lock.

isWaiter

boolean isWaiter(Locker locker)

Return true if locker is a waiter on this Lock. This method is only used by unit tests.

nWaiters

int nWaiters()

nOwners

int nOwners()

lock

LockAttemptResult lock(LockType requestType,
                       Locker locker,
                       boolean nonBlockingRequest,
                       MemoryBudget mb,
                       int lockTableIndex)
                       throws DatabaseException

Attempts to acquire the lock and returns the LockGrantType. Assumes we hold the lockTableLatch when entering this method.

Throws:

DatabaseException

release

java.util.Set<Locker> release(Locker locker,
                              MemoryBudget mb,
                              int lockTableIndex)

Releases a lock and moves the next waiter(s) to the owners.

Returns:

- null if we were not the owner, - a non-empty set if owners should be notified after releasing, - an empty set if no notification is required.

demote

void demote(Locker locker)

Downgrade a write lock to a read lock.

transfer

Lock transfer(java.lang.Long nodeId,
              Locker currentLocker,
              Locker destLocker,
              MemoryBudget mb,
              int lockTableIndex)
              throws DatabaseException

Transfer a lock from one transaction to another. Make sure that this destination locker is only present as a single reader or writer.

Throws:

DatabaseException

transferMultiple

Lock transferMultiple(java.lang.Long nodeId,
                      Locker currentLocker,
                      Locker[] destLockers,
                      MemoryBudget mb,
                      int lockTableIndex)
                      throws DatabaseException

Transfer a lock from one transaction to many others. Only really needed for case where a write handle lock is being transferred to multiple read handles.

Throws:

DatabaseException

getWriteOwnerLocker

Locker getWriteOwnerLocker()

Return the locker that has a write ownership on this lock. If no write owner exists, return null.

isThin

boolean isThin()

toString

java.lang.String toString()

Debug dumper.

Overrides:

toString in class java.lang.Object