org.apache.derby.iapi.services.locks

Class ShExLockable

java.lang.Object

org.apache.derby.iapi.services.locks.ShExLockable

All Implemented Interfaces:

Lockable

Direct Known Subclasses:

CacheLock, ClassLoaderLock

public class ShExLockable
extends java.lang.Object
implements Lockable

Constructor Summary

Constructors

Constructor and Description
ShExLockable()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	lockAttributes(int flag, java.util.Hashtable attributes) This lockable want to participate in the Virtual LockTable when we want to print LATCH information.
boolean	lockerAlwaysCompatible() Returns true if any lock request on a Lockable L in a compatibility space CS1 is compatible with any other lock held on L in CS1.
void	lockEvent(Latch lockInfo) Note the fact the object is locked.
boolean	requestCompatible(java.lang.Object requestedQualifier, java.lang.Object grantedQualifier) Return true if the requested qualifier is compatible with the already granted qualifier.
void	unlockEvent(Latch lockInfo) Note that the object has been unlocked Must only be called by the lock manager.

Methods inherited from class java.lang.Object

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

Constructor Detail

ShExLockable

public ShExLockable()

Method Detail

lockerAlwaysCompatible

public boolean lockerAlwaysCompatible()

Description copied from interface: Lockable

Returns true if any lock request on a Lockable L in a compatibility space CS1 is compatible with any other lock held on L in CS1.

Specified by:

lockerAlwaysCompatible in interface Lockable

See Also:

Lockable.lockerAlwaysCompatible()

requestCompatible

public boolean requestCompatible(java.lang.Object requestedQualifier,
                        java.lang.Object grantedQualifier)

Description copied from interface: Lockable

Return true if the requested qualifier is compatible with the already granted qualifier.

Specified by:

requestCompatible in interface Lockable

See Also:

Lockable.requestCompatible(java.lang.Object, java.lang.Object)

lockEvent

public void lockEvent(Latch lockInfo)

Description copied from interface: Lockable

Note the fact the object is locked. Performs required actions to ensure that unlockEvent() work correctly. This method does not actually perform any locking of the object, the locking mechanism is provided by the lock manager.

If the class supports multiple lockers of the object then this method will be called once per locker, each with their own qualifier.

Must only be called by the lock manager. Synchronization will be handled by the lock manager.

Specified by:

lockEvent in interface Lockable

See Also:

Lockable.lockEvent(org.apache.derby.iapi.services.locks.Latch)

unlockEvent

public void unlockEvent(Latch lockInfo)

Description copied from interface: Lockable

Note that the object has been unlocked

Must only be called by the lock manager. Synchronization will be handled by the lock manager.

Specified by:

unlockEvent in interface Lockable

See Also:

Lockable.unlockEvent(org.apache.derby.iapi.services.locks.Latch)

lockAttributes

public boolean lockAttributes(int flag,
                     java.util.Hashtable attributes)

This lockable want to participate in the Virtual LockTable when we want to print LATCH information. Any lockable object which DOES NOT want to participate should override this function.

Specified by:

lockAttributes in interface Lockable

Parameters:

flag - use the bits in this int to decide if the user is interested in this kind of lockable object. The bits are defined in VirtualLockTable. For instance, the user may only ask for TABLE_AND_ROWLOCK and if this is not a table or row lock, then don't participate.

attributes - if this decides to participate, put all relevant attributes into the Hashtable. The complete list of interesting attributes is listed in VirtualLockTable. The following attributes must be present for all participating lockables: VirtualLockTable.LOCKNAME, VirtualLockTable.LOCKTYPE, either VirtualLockTable.CONTAINERID or VirtualLockTable.CONGLOMID,

MT - this routine must be MP safe, caller will not be single threading the lock manager.

Returns:

true if this object has diagnostic information to add to the virtual lock table. If this object either does not want to participate in the diagnostic virtual lock table or none of the attributes requested are attributes of this lock, returns false.

See Also:

VirtualLockTable