com.sleepycat.je.txn

Class LockImpl

java.lang.Object

com.sleepycat.je.txn.LockImpl

public class LockImpl
extends Object

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

Constructor Summary

Constructors

Constructor and Description
LockImpl() Create a Lock.

Method Summary

Modifier and Type	Method and Description
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.
LockType	getOwnedLockType(Locker locker) Returns the LockType if the given locker owns this lock, or null if the lock is not owned.
Set<LockInfo>	getOwnersClone(boolean cloneLockInfo) Get a new Set of the owners.
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, boolean jumpAheadOfWaiters, MemoryBudget mb, int lockTableIndex) Attempts to acquire the lock and returns the LockGrantType.
int	nOwners()
int	nWaiters()
Set<Locker>	release(Locker locker, MemoryBudget mb, int lockTableIndex) Releases a lock and moves the next waiter(s) to the owners.
void	stealLock(@Nullable Locker locker, MemoryBudget mb, int lockTableIndex) Removes all owners except for the given owner (if non-null), and sets the Preempted property on the removed owners.
String	toString() Debug dumper.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LockImpl

public LockImpl()

Create a Lock.

Method Detail

getWaitersListClone

public List<LockInfo> getWaitersListClone()

Get a list of waiters for debugging and error messages.

flushWaiter

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

Remove this locker from the waiter list.

getOwnersClone

public Set<LockInfo> getOwnersClone(boolean cloneLockInfo)

Get a new Set of the owners.

isOwner

public boolean isOwner(Locker locker,
                       LockType lockType)

Return true if locker is an owner of this Lock for lockType, false otherwise.

isOwnedWriteLock

public boolean isOwnedWriteLock(Locker locker)

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

getOwnedLockType

public LockType getOwnedLockType(Locker locker)

Returns the LockType if the given locker owns this lock, or null if the lock is not owned.

isWaiter

public boolean isWaiter(Locker locker)

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

nWaiters

public int nWaiters()

nOwners

public int nOwners()

lock

public LockAttemptResult lock(LockType requestType,
                              Locker locker,
                              boolean nonBlockingRequest,
                              boolean jumpAheadOfWaiters,
                              MemoryBudget mb,
                              int lockTableIndex)

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

release

public 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.

stealLock

public void stealLock(@Nullable Locker locker,
                      MemoryBudget mb,
                      int lockTableIndex)

Removes all owners except for the given owner (if non-null), and sets the Preempted property on the removed owners.

demote

public void demote(Locker locker)

Downgrade a write lock to a read lock.

getWriteOwnerLocker

public Locker getWriteOwnerLocker()

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

isThin

public boolean isThin()

toString

public String toString()

Debug dumper.

Overrides:

toString in class Object