Apache Derby Database Engine and Embedded JDBC Driver 10.17.1.0 · org.apache.derby.impl.services.locks.LockTable

Method Summary

Modifier and Type	Method and Description
public void	addWaiters(Map<Object, Object> the map to add the waiters to waiters) Add all waiters in the lock table to the specified map.
public boolean	Returns: `true` if someone is blocked, `false` otherwise anyoneBlocked() Check whether there are anyone blocked in the lock table.
public int	getWaitTimeout() Get the wait timeout in milliseconds.
public Lock	Returns: a reference to the lock, or `null` if the lock couldn't be obtained immediately and the timeout was `NO_WAIT` or `LockOwner` had the `noWait` flag set lockObject(CompatibilitySpace the compatibility space compatibilitySpace, Lockable the object to lock ref, Object qualifier of the lock qualifier, int maximum time to wait in milliseconds (`C_LockFactory.NO_WAIT` means don't wait) timeout) Lock an object.
public void	oneLessWaiter() Notify the lock table that it has one less waiter.
public void	oneMoreWaiter() Notify the lock table that it has one more waiter.
public void	setDeadlockTimeout(int deadlock timeout in milliseconds timeout) Set the deadlock timeout.
public void	setDeadlockTrace(boolean `true` enables tracing, `false` disables tracing flag) Enable or disable tracing of deadlocks.
public void	setWaitTimeout(int wait timeout in milliseconds timeout) Set the wait timeout.
public Map<K, V>	Returns: a shallow clone of the lock table shallowClone() Create a map containing a snapshot of all the (`Lockable`, `LockControl`) pairs in the lock table.
public void	unlock(Latch the lock to unlock item, int the number of times to unlock the item; or zero, meaning take the unlock count from the item unlockCount) Unlock an object previously locked by `lockObject()`.
public Lock	Returns: the corresponding lock in the group map, or `null` if the object was not unlocked unlockReference(CompatibilitySpace the compatibility space space, Lockable a reference to the locked object ref, Object qualifier of the lock qualifier, Map<K, V> a map representing the locks in a group group) Unlock an object once if it is present in the specified group.
public boolean	Returns: `true` if the object was locked, or `false` if the object couldn't be locked immediately and timeout was `NO_WAIT` or `LockOwner` had the `noWait` flag set zeroDurationLockObject(CompatibilitySpace the compatibility space space, Lockable a reference to the locked object ref, Object qualifier of the lock qualifier, int maximum time to wait in milliseconds (`C_LockFactory.NO_WAIT` means don't wait) timeout) Lock an object and release the lock immediately.

Method Detail

addWaiters back to summary

addWaiters	back to summary
public void addWaiters(Map<Object, Object> waiters) Add all waiters in the lock table to the specified map. Parameters waiters:Map<Object, Object> the map to add the waiters to See Also `LockControl#addWaiters`

public void addWaiters(Map<Object, Object> waiters)

Add all waiters in the lock table to the specified map.

Parameters

waiters:Map<Object, Object>: the map to add the waiters to

See Also

LockControl#addWaiters

anyoneBlocked back to summary

anyoneBlocked	back to summary
public boolean anyoneBlocked() Check whether there are anyone blocked in the lock table. Returns:boolean `true` if someone is blocked, `false` otherwise

public boolean anyoneBlocked()

Check whether there are anyone blocked in the lock table.

Returns:boolean: true if someone is blocked, false otherwise

getWaitTimeout	back to summary
public int getWaitTimeout() Get the wait timeout in milliseconds.

lockObject back to summary

lockObject	back to summary
public Lock lockObject(CompatibilitySpace compatibilitySpace, Lockable ref, Object qualifier, int timeout) throws StandardException Lock an object. Parameters compatibilitySpace:CompatibilitySpace the compatibility space ref:Lockable the object to lock qualifier:Object qualifier of the lock timeout:int maximum time to wait in milliseconds (`C_LockFactory.NO_WAIT` means don't wait) Returns:Lock a reference to the lock, or `null` if the lock couldn't be obtained immediately and the timeout was `NO_WAIT` or `LockOwner` had the `noWait` flag set Exceptions StandardException: if the lock could not be obtained

public Lock lockObject(CompatibilitySpace compatibilitySpace, Lockable ref, Object qualifier, int timeout) throws StandardException

Lock an object.

Parameters

compatibilitySpace:CompatibilitySpace: the compatibility space
ref:Lockable: the object to lock
qualifier:Object: qualifier of the lock
timeout:int: maximum time to wait in milliseconds (C_LockFactory.NO_WAIT means don't wait)

Returns:Lock

a reference to the lock, or null if the lock couldn't be obtained immediately and the timeout was NO_WAIT or LockOwner had the noWait flag set

Exceptions

StandardException:: if the lock could not be obtained

oneLessWaiter	back to summary
public void oneLessWaiter() Notify the lock table that it has one less waiter.

oneMoreWaiter	back to summary
public void oneMoreWaiter() Notify the lock table that it has one more waiter.

setDeadlockTimeout	back to summary
public void setDeadlockTimeout(int timeout) Set the deadlock timeout. Parameters timeout:int deadlock timeout in milliseconds

setDeadlockTimeout

back to summary

public void setDeadlockTimeout(int timeout)

Set the deadlock timeout.

Parameters

timeout:int: deadlock timeout in milliseconds

setDeadlockTrace back to summary

setDeadlockTrace	back to summary
public void setDeadlockTrace(boolean flag) Enable or disable tracing of deadlocks. Parameters flag:boolean `true` enables tracing, `false` disables tracing

public void setDeadlockTrace(boolean flag)

Enable or disable tracing of deadlocks.

Parameters

flag:boolean: true enables tracing, false disables tracing

setWaitTimeout	back to summary
public void setWaitTimeout(int timeout) Set the wait timeout. Parameters timeout:int wait timeout in milliseconds

setWaitTimeout

back to summary

public void setWaitTimeout(int timeout)

Set the wait timeout.

Parameters

timeout:int: wait timeout in milliseconds

shallowClone back to summary

shallowClone	back to summary
public Map<K, V> shallowClone() Create a map containing a snapshot of all the (`Lockable`, `LockControl`) pairs in the lock table. Returns:Map<K, V> a shallow clone of the lock table

public Map<K, V> shallowClone()

Create a map containing a snapshot of all the (Lockable, LockControl) pairs in the lock table.

Returns:Map<K, V>: a shallow clone of the lock table

unlock back to summary

unlock	back to summary
public void unlock(Latch item, int unlockCount) Unlock an object previously locked by `lockObject()`. Parameters item:Latch the lock to unlock unlockCount:int the number of times to unlock the item; or zero, meaning take the unlock count from the item

public void unlock(Latch item, int unlockCount)

Unlock an object previously locked by lockObject().

Parameters

item:Latch: the lock to unlock
unlockCount:int: the number of times to unlock the item; or zero, meaning take the unlock count from the item

unlockReference back to summary

unlockReference	back to summary
public Lock unlockReference(CompatibilitySpace space, Lockable ref, Object qualifier, Map<K, V> group) Unlock an object once if it is present in the specified group. Also remove the object from the group. Parameters space:CompatibilitySpace the compatibility space ref:Lockable a reference to the locked object qualifier:Object qualifier of the lock group:Map<K, V> a map representing the locks in a group Returns:Lock the corresponding lock in the group map, or `null` if the object was not unlocked

public Lock unlockReference(CompatibilitySpace space, Lockable ref, Object qualifier, Map<K, V> group)

Unlock an object once if it is present in the specified group. Also remove the object from the group.

Parameters

space:CompatibilitySpace: the compatibility space
ref:Lockable: a reference to the locked object
qualifier:Object: qualifier of the lock
group:Map<K, V>: a map representing the locks in a group

Returns:Lock

the corresponding lock in the group map, or null if the object was not unlocked

zeroDurationLockObject back to summary

zeroDurationLockObject	back to summary
public boolean zeroDurationLockObject(CompatibilitySpace space, Lockable ref, Object qualifier, int timeout) throws StandardException Lock an object and release the lock immediately. Equivalent to Lock lock = lockTable.lockObject(space, ref, qualifier, timeout); lockTable.unlock(lock, 1); except that the implementation might be more efficient. Parameters space:CompatibilitySpace the compatibility space ref:Lockable a reference to the locked object qualifier:Object qualifier of the lock timeout:int maximum time to wait in milliseconds (`C_LockFactory.NO_WAIT` means don't wait) Returns:boolean `true` if the object was locked, or `false` if the object couldn't be locked immediately and timeout was `NO_WAIT` or `LockOwner` had the `noWait` flag set Exceptions StandardException: if the lock could not be obtained

public boolean zeroDurationLockObject(CompatibilitySpace space, Lockable ref, Object qualifier, int timeout) throws StandardException

Lock an object and release the lock immediately. Equivalent to

Lock lock = lockTable.lockObject(space, ref, qualifier, timeout);
lockTable.unlock(lock, 1);

except that the implementation might be more efficient.

Parameters

space:CompatibilitySpace: the compatibility space
ref:Lockable: a reference to the locked object
qualifier:Object: qualifier of the lock
timeout:int: maximum time to wait in milliseconds (C_LockFactory.NO_WAIT means don't wait)

Returns:boolean

true if the object was locked, or false if the object couldn't be locked immediately and timeout was NO_WAIT or LockOwner had the noWait flag set

Exceptions

StandardException:: if the lock could not be obtained

pack-priv Interface LockTable

Method Summary

Method Detail