org.apache.derby.impl.services.locks

Class ActiveLock

java.lang.Object

org.apache.derby.impl.services.locks.ActiveLock

All Implemented Interfaces:

Latch, Control

public final class ActiveLock
extends java.lang.Object

A Lock represents a granted or waiting lock request.
MT - Mutable - Immutable identity : Thread Aware

Method Summary

Modifier and Type	Method and Description
void	addWaiters(java.util.Map waiters)
boolean	equals(java.lang.Object other)
ActiveLock	firstWaiter()
CompatibilitySpace	getCompatabilitySpace() Return the compatibility space this lock is held in.
int	getCount() Return the count of locks.
org.apache.derby.impl.services.locks.Lock	getFirstGrant()
java.util.List	getGranted()
org.apache.derby.impl.services.locks.Lock	getLock(CompatibilitySpace compatibilitySpace, java.lang.Object qualifier)
Lockable	getLockable() Return the object this lock is held on MT - Thread safe
org.apache.derby.impl.services.locks.LockControl	getLockControl()
java.lang.Object	getQualifier() Return the qualifier lock was obtained with.
java.util.List	getWaiting()
int	hashCode()
boolean	isEmpty()
boolean	isGrantable(boolean noWaitersBeforeMe, CompatibilitySpace compatibilitySpace, java.lang.Object requestQualifier)
Control	shallowClone() We can return ourselves here because our identity is immutable and what we returned will not be accessed as a Lock, so the count cannot be changed.
boolean	unlock(Latch lockInGroup, int unlockCount)

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Method Detail

getLockable

public final Lockable getLockable()

Return the object this lock is held on MT - Thread safe

Specified by:

getLockable in interface Latch

Specified by:

getLockable in interface Control

getCompatabilitySpace

public final CompatibilitySpace getCompatabilitySpace()

Return the compatibility space this lock is held in. MT - Thread safe

Specified by:

getCompatabilitySpace in interface Latch

getQualifier

public final java.lang.Object getQualifier()

Return the qualifier lock was obtained with. MT - Thread safe

Specified by:

getQualifier in interface Latch

getCount

public final int getCount()

Return the count of locks. MT - Thread safe

Specified by:

getCount in interface Latch

hashCode

public final int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public final boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object

getLockControl

public org.apache.derby.impl.services.locks.LockControl getLockControl()

Specified by:

getLockControl in interface Control

getLock

public org.apache.derby.impl.services.locks.Lock getLock(CompatibilitySpace compatibilitySpace,
                                                         java.lang.Object qualifier)

Specified by:

getLock in interface Control

shallowClone

public Control shallowClone()

We can return ourselves here because our identity is immutable and what we returned will not be accessed as a Lock, so the count cannot be changed.

Specified by:

shallowClone in interface Control

firstWaiter

public ActiveLock firstWaiter()

Specified by:

firstWaiter in interface Control

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Control

unlock

public boolean unlock(Latch lockInGroup,
                      int unlockCount)

Specified by:

unlock in interface Control

addWaiters

public void addWaiters(java.util.Map waiters)

Specified by:

addWaiters in interface Control

getFirstGrant

public org.apache.derby.impl.services.locks.Lock getFirstGrant()

Specified by:

getFirstGrant in interface Control

getGranted

public java.util.List getGranted()

Specified by:

getGranted in interface Control

getWaiting

public java.util.List getWaiting()

Specified by:

getWaiting in interface Control

isGrantable

public boolean isGrantable(boolean noWaitersBeforeMe,
                           CompatibilitySpace compatibilitySpace,
                           java.lang.Object requestQualifier)

Specified by:

isGrantable in interface Control