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

Method Summary

Modifier and Type	Method and Description
public boolean	Returns: true if someone is blocked anyoneBlocked() Returns true if locks held by anyone are blocking anyone else
public boolean	Returns: true if locks matching the arguments are held areLocksHeld(CompatibilitySpace A lock space compatibilitySpace, Object handle of group that objects were locked with. group) Return true if locks are held in this compatibility space and this group.
public boolean	Returns: true if locks matching the arguments are held areLocksHeld(CompatibilitySpace A lock space compatibilitySpace) Return true if locks are held in this compatibility space.
public void	clearLimit(CompatibilitySpace A lock space compatibilitySpace, Object A group group) Clear a limit set by setLimit.
public CompatibilitySpace	Returns: an object which represents a compatibility space createCompatibilitySpace(LockOwner the owner of the compatibility space (typically a transaction object). Might be `null`. owner) Create an object which can be used as a compatibility space.
public int	Returns: the lock timeout in milliseconds getWaitTimeout() Get the lock timeout in milliseconds.
public boolean	Returns: true if the indicated lock is held isLockHeld(CompatibilitySpace A lock space compatibilitySpace, Object A group group, Lockable Something which can be locked ref, Object The kind of lock qualifier) Check to see if a specific lock is held.
public boolean	Returns: true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted. lockObject(CompatibilitySpace object defining compatibility space compatibilitySpace, Object handle of group, must be private to a thread. group, Lockable reference to object to be locked ref, Object A qualification of the request. qualifier, int the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait. timeout) Lock an object within a compatibility space and associate the lock with a group object, waits up to timeout milli-seconds for the object to become unlocked.
public Enumeration<E>	Returns: a virtual lock table makeVirtualLockTable() Make a virtual lock table for diagnostics.
public void	setLimit(CompatibilitySpace A lock space compatibilitySpace, Object A group group, int A limit for the group limit, Limit Code to call when the limit is reached callback) Install a limit that is called when the size of the group exceeds the required limit.
public void	transfer(CompatibilitySpace A lock space compatibilitySpace, Object The source group oldGroup, Object The target group newGroup) Transfer a set of locks from one group to another.
public int	Returns: number of locks released (one or zero). unlock(CompatibilitySpace object defining compatibility space compatibilitySpace, Object handle of group. group, Lockable Reference to object to be unlocked. ref, Object qualifier of lock to be unlocked qualifier) Unlock a single lock on a single object held within this compatibility space and locked with the supplied qualifier.
public void	unlockGroup(CompatibilitySpace object defining compatibility space compatibilitySpace, Object handle of group that objects were locked with. group) Unlock all locks in a group.
public void	unlockGroup(CompatibilitySpace A lock space compatibilitySpace, Object A group group, Matchable The key key) Unlock all locks on a group that match the passed in value.
public boolean	Returns: true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted. zeroDurationlockObject(CompatibilitySpace object defining compatibility space compatibilitySpace, Lockable reference to object to be locked ref, Object A qualification of the request. qualifier, int the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait. timeout) Lock an object with zero duration within a compatibility space, waits up to timeout milli-seconds for the object to become unlocked.

Inherited from org.apache.derby.iapi.services.property.PropertySetCallback:: apply init map validate

Method Detail

anyoneBlocked	back to summary
public boolean anyoneBlocked() Returns true if locks held by anyone are blocking anyone else Returns:boolean true if someone is blocked

anyoneBlocked

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public boolean anyoneBlocked()

Returns true if locks held by anyone are blocking anyone else

Returns:boolean: true if someone is blocked

areLocksHeld	back to summary
public boolean areLocksHeld(CompatibilitySpace compatibilitySpace, Object group) Return true if locks are held in this compatibility space and this group. Parameters compatibilitySpace:CompatibilitySpace A lock space group:Object handle of group that objects were locked with. Returns:boolean true if locks matching the arguments are held

areLocksHeld

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public boolean areLocksHeld(CompatibilitySpace compatibilitySpace, Object group)

Return true if locks are held in this compatibility space and this group.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space
group:Object: handle of group that objects were locked with.

Returns:boolean

true if locks matching the arguments are held

areLocksHeld	back to summary
public boolean areLocksHeld(CompatibilitySpace compatibilitySpace) Return true if locks are held in this compatibility space. Parameters compatibilitySpace:CompatibilitySpace A lock space Returns:boolean true if locks matching the arguments are held

areLocksHeld

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public boolean areLocksHeld(CompatibilitySpace compatibilitySpace)

Return true if locks are held in this compatibility space.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space

Returns:boolean

true if locks matching the arguments are held

clearLimit	back to summary
public void clearLimit(CompatibilitySpace compatibilitySpace, Object group) Clear a limit set by setLimit. Parameters compatibilitySpace:CompatibilitySpace A lock space group:Object A group

clearLimit

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public void clearLimit(CompatibilitySpace compatibilitySpace, Object group)

Clear a limit set by setLimit.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space
group:Object: A group

createCompatibilitySpace back to summary

createCompatibilitySpace	back to summary
public CompatibilitySpace createCompatibilitySpace(LockOwner owner) Create an object which can be used as a compatibility space. A compatibility space object can only be used in the `LockFactory` that created it. Parameters owner:LockOwner the owner of the compatibility space (typically a transaction object). Might be `null`. Returns:CompatibilitySpace an object which represents a compatibility space

public CompatibilitySpace createCompatibilitySpace(LockOwner owner)

Create an object which can be used as a compatibility space. A compatibility space object can only be used in the LockFactory that created it.

Parameters

owner:LockOwner: the owner of the compatibility space (typically a transaction object). Might be null.

Returns:CompatibilitySpace

an object which represents a compatibility space

getWaitTimeout	back to summary
public int getWaitTimeout() Get the lock timeout in milliseconds. A negative number means that there is no timeout. Returns:int the lock timeout in milliseconds

getWaitTimeout

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public int getWaitTimeout()

Get the lock timeout in milliseconds. A negative number means that there is no timeout.

Returns:int: the lock timeout in milliseconds

isLockHeld	back to summary
public boolean isLockHeld(CompatibilitySpace compatibilitySpace, Object group, Lockable ref, Object qualifier) Check to see if a specific lock is held. Parameters compatibilitySpace:CompatibilitySpace A lock space group:Object A group ref:Lockable Something which can be locked qualifier:Object The kind of lock Returns:boolean true if the indicated lock is held

isLockHeld

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public boolean isLockHeld(CompatibilitySpace compatibilitySpace, Object group, Lockable ref, Object qualifier)

Check to see if a specific lock is held.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space
group:Object: A group
ref:Lockable: Something which can be locked
qualifier:Object: The kind of lock

Returns:boolean

true if the indicated lock is held

lockObject	back to summary
public boolean lockObject(CompatibilitySpace compatibilitySpace, Object group, Lockable ref, Object qualifier, int timeout) throws StandardException Lock an object within a compatibility 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 compatible and granted by the lock manager if the trio {compatibilitySpace, ref, qualifier} are equal (i.e. reference equality for qualifier and compatibilitySpace, equals() method for ref). Granted by the lock manager means that the Lockable object may or may not be queried to see if the request is compatible. A compatibility space is not assumed to be owned by a single thread. Parameters compatibilitySpace:CompatibilitySpace object defining compatibility space group:Object handle of group, must be private to a thread. ref:Lockable reference to object to be locked qualifier:Object A qualification of the request. timeout:int the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait. Returns:boolean true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted. Exceptions StandardException: if a deadlock has occurred (message id will be LockFactory.Deadlock), or if the wait for the lock timed out (message id will be LockFactory.TimeOut), or if another thread interrupted this thread while it was waiting for the lock (this will be a StandardException with a nested InterruptedException, and the message id will be LockFactory.InterruptedExceptionId), or if any other error occurs when locking the object

lockObject

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

Lock an object within a compatibility 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 compatible and granted by the lock manager if the trio {compatibilitySpace, ref, qualifier} are equal (i.e. reference equality for qualifier and compatibilitySpace, equals() method for ref). Granted by the lock manager means that the Lockable object may or may not be queried to see if the request is compatible.
A compatibility space is not assumed to be owned by a single thread.

Parameters

compatibilitySpace:CompatibilitySpace: object defining compatibility space
group:Object: handle of group, must be private to a thread.
ref:Lockable: reference to object to be locked
qualifier:Object: A qualification of the request.
timeout:int: the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait.

Returns:boolean

true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted.

Exceptions

StandardException:: if a deadlock has occurred (message id will be LockFactory.Deadlock), or if the wait for the lock timed out (message id will be LockFactory.TimeOut), or if another thread interrupted this thread while it was waiting for the lock (this will be a StandardException with a nested InterruptedException, and the message id will be LockFactory.InterruptedExceptionId), or if any other error occurs when locking the object

makeVirtualLockTable	back to summary
public Enumeration<E> makeVirtualLockTable() Make a virtual lock table for diagnostics. Returns:Enumeration<E> a virtual lock table

makeVirtualLockTable

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public Enumeration<E> makeVirtualLockTable()

Make a virtual lock table for diagnostics.

Returns:Enumeration<E>: a virtual lock table

setLimit back to summary

setLimit	back to summary
public void setLimit(CompatibilitySpace compatibilitySpace, 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. 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. Parameters compatibilitySpace:CompatibilitySpace A lock space group:Object A group limit:int A limit for the group callback:Limit Code to call when the limit is reached See Also `Limit`

public void setLimit(CompatibilitySpace compatibilitySpace, 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. 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.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space
group:Object: A group
limit:int: A limit for the group
callback:Limit: Code to call when the limit is reached

See Also

Limit

transfer	back to summary
public void transfer(CompatibilitySpace compatibilitySpace, Object oldGroup, Object newGroup) Transfer a set of locks from one group to another. Parameters compatibilitySpace:CompatibilitySpace A lock space oldGroup:Object The source group newGroup:Object The target group

transfer

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public void transfer(CompatibilitySpace compatibilitySpace, Object oldGroup, Object newGroup)

Transfer a set of locks from one group to another.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space
oldGroup:Object: The source group
newGroup:Object: The target group

unlock	back to summary
public int unlock(CompatibilitySpace compatibilitySpace, Object group, Lockable ref, Object qualifier) Unlock a single lock on a single object held within this compatibility space and locked with the supplied qualifier. Parameters compatibilitySpace:CompatibilitySpace object defining compatibility space group:Object handle of group. ref:Lockable Reference to object to be unlocked. qualifier:Object qualifier of lock to be unlocked Returns:int number of locks released (one or zero).

unlock

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public int unlock(CompatibilitySpace compatibilitySpace, Object group, Lockable ref, Object qualifier)

Unlock a single lock on a single object held within this compatibility space and locked with the supplied qualifier.

Parameters

compatibilitySpace:CompatibilitySpace: object defining compatibility space
group:Object: handle of group.
ref:Lockable: Reference to object to be unlocked.
qualifier:Object: qualifier of lock to be unlocked

Returns:int

number of locks released (one or zero).

unlockGroup	back to summary
public void unlockGroup(CompatibilitySpace compatibilitySpace, Object group) Unlock all locks in a group. Parameters compatibilitySpace:CompatibilitySpace object defining compatibility space group:Object handle of group that objects were locked with.

unlockGroup

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public void unlockGroup(CompatibilitySpace compatibilitySpace, Object group)

Unlock all locks in a group.

Parameters

compatibilitySpace:CompatibilitySpace: object defining compatibility space
group:Object: handle of group that objects were locked with.

unlockGroup	back to summary
public void unlockGroup(CompatibilitySpace compatibilitySpace, Object group, Matchable key) Unlock all locks on a group that match the passed in value. Parameters compatibilitySpace:CompatibilitySpace A lock space group:Object A group key:Matchable The key

unlockGroup

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public void unlockGroup(CompatibilitySpace compatibilitySpace, Object group, Matchable key)

Unlock all locks on a group that match the passed in value.

Parameters

compatibilitySpace:CompatibilitySpace: A lock space
group:Object: A group
key:Matchable: The key

zeroDurationlockObject	back to summary
public boolean zeroDurationlockObject(CompatibilitySpace compatibilitySpace, Lockable ref, Object qualifier, int timeout) throws StandardException Lock an object with zero duration within a compatibility 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 compatible and granted by the lock manager if the trio {compatibilitySpace, ref, qualifier} are equal (i.e. reference equality for qualifier and compatibilitySpace, equals() method for ref). Granted by the lock manager means that the Lockable object may or may not be queried to see if the request is compatible. A compatibility space is not assumed to be owned by a single thread. Parameters compatibilitySpace:CompatibilitySpace object defining compatibility space ref:Lockable reference to object to be locked qualifier:Object A qualification of the request. timeout:int the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait. Returns:boolean true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted. Exceptions StandardException: if a deadlock has occurred (message id will be LockFactory.Deadlock), or if the wait for the lock timed out (message id will be LockFactory.TimeOut), or if another thread interrupted this thread while it was waiting for the lock (this will be a StandardException with a nested InterruptedException, and the message id will be LockFactory.InterruptedExceptionId), or if any other error occurs when locking the object

zeroDurationlockObject

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public boolean zeroDurationlockObject(CompatibilitySpace compatibilitySpace, Lockable ref, Object qualifier, int timeout) throws StandardException

Lock an object with zero duration within a compatibility 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.

Parameters

compatibilitySpace:CompatibilitySpace: object defining compatibility space
ref:Lockable: reference to object to be locked
qualifier:Object: A qualification of the request.
timeout:int: the maximum time to wait in milliseconds, LockFactory.NO_WAIT means don't wait.

Returns:boolean

true if the lock was obtained, false if timeout is equal to LockFactory.NO_WAIT and the lock could not be granted.

Exceptions

StandardException:: if a deadlock has occurred (message id will be LockFactory.Deadlock), or if the wait for the lock timed out (message id will be LockFactory.TimeOut), or if another thread interrupted this thread while it was waiting for the lock (this will be a StandardException with a nested InterruptedException, and the message id will be LockFactory.InterruptedExceptionId), or if any other error occurs when locking the object

public Interface LockFactory

Method Summary

Method Detail