| org.apache.derby.iapi.services.locks.LockFactory
All known Subclasses: org.apache.derby.impl.services.locks.SinglePool,
| LockFactory | | public interface LockFactory extends PropertySetCallback(Code) | | Generic locking of objects. Enables deadlock detection.
MT - Mutable - Container Object - Thread Safe
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| Method Summary | |
| public boolean | anyoneBlocked()
| | public boolean | areLocksHeld(Object compatabilitySpace, Object group)
Return true if locks are held in this compatability space and
this group. | | public boolean | areLocksHeld(Object compatabilitySpace)
Return true if locks are held in this compatability space. | | public void | clearLimit(Object compatabilitySpace, Object group)
Clear a limit set by setLimit. | | public boolean | isLockHeld(Object compatabilitySpace, Object group, Lockable ref, Object qualifier)
Check to see if a specific lock is held. | | public boolean | latchObject(Object compatabilitySpace, Lockable ref, Object qualifier, int timeout)
Latch an object. | | public boolean | lockObject(Object compatabilitySpace, Object group, Lockable ref, Object qualifier, int timeout)
Lock an object within a compatability space
and associate the lock with a group object,
waits up to timeout milli-seconds for the object to become unlocked. | | public boolean | lockObject(Object group, Lockable ref, Object qualifier, int timeout, Latch latch)
Lock an object within a compatability space
and associate the lock with a group object,
In addition a held latch is passed in. | | public Enumeration | makeVirtualLockTable()
Make a virtual lock table for diagnostics. | | public void | setLimit(Object compatabilitySpace, Object group, int limit, Limit callback)
Install a limit that is called when the size of the group exceeds
the required limit.
It is not guaranteed that the callback method (Limit.reached) is
called as soon as the group size exceeds the given limit.
If the callback method does not result in a decrease in the
number of locks held then the lock factory implementation
may delay calling the method again. | | public void | transfer(Object compatabilitySpace, Object oldGroup, Object newGroup)
Transfer a set of locks from one group to another. | | public void | unlatch(Latch heldLatch)
Unlatch an object. | | public int | unlock(Object compatabilitySpace, Object group, Lockable ref, Object qualifier)
Unlock a single lock on a single object held within this compatability space
that was locked with the supplied qualifier. | | public void | unlockGroup(Object compatabilitySpace, Object group)
Unlock all locks in a group. | | public void | unlockGroup(Object compatabilitySpace, Object group, Matchable key)
Unlock all locks on a group that match the passed in value. | | public boolean | zeroDurationlockObject(Object compatabilitySpace, Lockable ref, Object qualifier, int timeout)
Lock an object with zero duration within a compatability space,
waits up to timeout milli-seconds for the object to become unlocked. |
| anyoneBlocked | | public boolean anyoneBlocked()(Code) | | Returns true if locks held by anyone are blocking anyone else
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| areLocksHeld | | public boolean areLocksHeld(Object compatabilitySpace, Object group)(Code) | | Return true if locks are held in this compatability space and
this group.
Parameters:
group - handle of group that objects were locked with. |
| areLocksHeld | | public boolean areLocksHeld(Object compatabilitySpace)(Code) | | Return true if locks are held in this compatability space.
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| clearLimit | | public void clearLimit(Object compatabilitySpace, Object group)(Code) | | Clear a limit set by setLimit.
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| latchObject | | public boolean latchObject(Object compatabilitySpace, Lockable ref, Object qualifier, int timeout) throws StandardException(Code) | | Latch an object. A latch is a lock without a group.
This means that it must be released explicitly by the owner.
A latch is not released by any unlock methods, it must be
released by the unlatch method. A latch is assumed to only
be held by one locker at a time.
The first argument passed to lockEvent() is the Latch that
is to be used in the unlatch() call.
The firstArgument passed to unlockEvent() should be ignored.
true if the latch was obtained,false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted.
exception:
org.apache.derby.iapi.error.StandardException - A deadlock has occured (message id will be LockFactory.Deadlock)
exception:
org.apache.derby.iapi.error.StandardException - Another thread interupted this thread whileit was waiting for the latch. This will be a StandardException with a nested java.lang.InterruptedException exception,(message id will be LockFactory.InterruptedExceptionId)
exception:
StandardException - Standard Cloudscape error policy. |
| lockObject | | public boolean lockObject(Object compatabilitySpace, Object group, Lockable ref, Object qualifier, int timeout) throws StandardException(Code) | | Lock an object within a compatability space
and associate the lock with a group object,
waits up to timeout milli-seconds for the object to become unlocked. A
timeout of 0 means do not wait for the lock to be unlocked.
Note the actual time waited is approximate.
A compatibility space in an space where lock requests are assumed to be
compatabile and granted by the lock manager if the trio
{compatabilitySpace, ref, qualifier} are equal (i.e. reference equality
for qualifier, equals() method
for compatabilitySpace and ref ). A typical reference to use for the compatability
space is a reference to an object representing a transaction.
Granted by the lock manager means that the Lockable object may or may
not be queried to see if the request is compatible.
A compatability space is not assumed to be owned by a single thread.
Parameters:
compatabilitySpace - object defining compatability space (by value)
Parameters:
group - handle of group, must be private to a thread.
Parameters:
ref - reference to object to be locked
Parameters:
qualifier - A qualification of the request.
Parameters:
timeout - the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait. true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lockcould not be granted.
exception:
org.apache.derby.iapi.error.StandardException - A deadlock has occured (message id will be LockFactory.Deadlock)
exception:
org.apache.derby.iapi.error.StandardException - The wait for the lock timed out (message id will be LockFactory.TimeOut).
exception:
org.apache.derby.iapi.error.StandardException - Another thread interupted this thread whileit was waiting for the lock. This will be a StandardException with a nested java.lang.InterruptedException exception,(message id will be LockFactory.InterruptedExceptionId)
exception:
StandardException - Standard Cloudscape error policy. |
| lockObject | | public boolean lockObject(Object group, Lockable ref, Object qualifier, int timeout, Latch latch) throws StandardException(Code) | | Lock an object within a compatability space
and associate the lock with a group object,
In addition a held latch is passed in. If the lock
cannot be granted immediately, the latch will be released
and relatched after the lock is obtained. If the lock can be granted
immediately the latch is not released.
The compatability space of the request is defined by the compatability
space of the latch.
Parameters:
group - handle of group, must be private to a compatability space.
Parameters:
ref - reference to object to be locked
Parameters:
qualifier - A qualification of the request.
Parameters:
timeout - amount of time to wait, NO_WAIT is not supported
Parameters:
latch - latch to be atomically released/re-latched in a wait. true if the latch was released, false otherwise.
exception:
org.apache.derby.iapi.error.StandardException - A deadlock has occured (message id will be LockFactory.Deadlock)
exception:
org.apache.derby.iapi.error.StandardException - Another thread interupted this thread whileit was waiting for the lock. This will be a StandardException with a nested java.lang.InterruptedException exception,(message id will be LockFactory.InterruptedExceptionId)
exception:
StandardException - Standard Cloudscape error policy. |
| makeVirtualLockTable | | public Enumeration makeVirtualLockTable()(Code) | | Make a virtual lock table for diagnostics.
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| setLimit | | public void setLimit(Object compatabilitySpace, Object group, int limit, Limit callback)(Code) | | Install a limit that is called when the size of the group exceeds
the required limit.
It is not guaranteed that the callback method (Limit.reached) is
called as soon as the group size exceeds the given limit.
If the callback method does not result in a decrease in the
number of locks held then the lock factory implementation
may delay calling the method again. E.g. with a limit
of 500 and a reached() method that does nothing, may result
in the call back method only being called when the group size reaches
550.
Only one limit may be in place for a group at any time.
See Also: Limit |
| transfer | | public void transfer(Object compatabilitySpace, Object oldGroup, Object newGroup)(Code) | | Transfer a set of locks from one group to another.
|
| unlatch | | public void unlatch(Latch heldLatch)(Code) | | Unlatch an object.
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| unlock | | public int unlock(Object compatabilitySpace, Object group, Lockable ref, Object qualifier)(Code) | | Unlock a single lock on a single object held within this compatability space
that was locked with the supplied qualifier.
Parameters:
compatabilitySpace - object defining compatability space (by value)
Parameters:
group - handle of group.
Parameters:
ref - Reference to object to be unlocked.
Parameters:
qualifier - qualifier of lock to be unlocked number of locks released (one or zero). |
| unlockGroup | | public void unlockGroup(Object compatabilitySpace, Object group)(Code) | | Unlock all locks in a group.
Parameters:
group - handle of group that objects were locked with. |
| unlockGroup | | public void unlockGroup(Object compatabilitySpace, Object group, Matchable key)(Code) | | Unlock all locks on a group that match the passed in value.
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| zeroDurationlockObject | | public boolean zeroDurationlockObject(Object compatabilitySpace, Lockable ref, Object qualifier, int timeout) throws StandardException(Code) | | Lock an object with zero duration within a compatability space,
waits up to timeout milli-seconds for the object to become unlocked. A
timeout of 0 means do not wait for the lock to be unlocked.
Note the actual time waited is approximate.
Zero duration means the lock is released as soon as it is obtained.
A compatibility space in an space where lock requests are assumed to be
compatabile and granted by the lock manager if the trio
{compatabilitySpace, ref, qualifier} are equal (i.e. reference equality
for qualifier, equals() method
for compatabilitySpace and ref ). A typical reference to use for the compatability
space is a reference to an object representing a transaction.
Granted by the lock manager means that the Lockable object may or may
not be queried to see if the request is compatible.
A compatability space is not assumed to be owned by a single thread.
Parameters:
compatabilitySpace - object defining compatability space (by value)
Parameters:
ref - reference to object to be locked
Parameters:
qualifier - A qualification of the request.
Parameters:
timeout - the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait. true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lockcould not be granted.
exception:
org.apache.derby.iapi.error.StandardException - A deadlock has occured (message id will be LockFactory.Deadlock)
exception:
org.apache.derby.iapi.error.StandardException - The wait for the lock timed out (message id will be LockFactory.TimeOut).
exception:
org.apache.derby.iapi.error.StandardException - Another thread interupted this thread whileit was waiting for the lock. This will be a StandardException with a nested java.lang.InterruptedException exception,(message id will be LockFactory.InterruptedExceptionId)
exception:
StandardException - Standard Cloudscape error policy. |
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