org.abstracthorizon.danube.webdav.lock.impl
Class SimpleInMemoryLockingMechanism

java.lang.Object
  org.abstracthorizon.danube.webdav.lock.impl.SimpleInMemoryLockingMechanism

All Implemented Interfaces:

LockingMechanism

Direct Known Subclasses:

FSLockingMechanism

public class SimpleInMemoryLockingMechanism
extends Object
implements LockingMechanism

Simple, in-memory locking mechanism

Author:

Daniel Sendula

Field Summary

protected int	harvestMinimumInterval Minimal interval timed out locks are removed.
protected Map<Lock,Collection<Object>>	lockResources Map of locks to resources
protected long	nextHarvested Time locks can be harvesed as the earliest
protected Map<Object,Collection<Lock>>	resourcesLocks Map of resources to locks
protected Map<String,Lock>	tokenLocks Map of tokens to locks

Fields inherited from interface org.abstracthorizon.danube.webdav.lock.LockingMechanism

SCOPE_EXCLUSIVE, SCOPE_NONE, SCOPE_SHARED, TYPE_WRITE

Constructor Summary

SimpleInMemoryLockingMechanism()
Constructor

Method Summary

Lock	createLock(int type, int scope, Object owner, Timeout timeout, int depth) Creates the lock
protected Lock	createLockImpl(int type, int scope, Object owner, Timeout timeout, int depth) Constructs lock object
Lock	findLock(String token) Retunrs the lock with the given token or null
int	getHarvestMinimumInterval() Returns minimal harvest interval in miliseconds
Lock[]	getLocks(Object resource) Returns locks for the given resource
Object[]	getResources(Lock lock) Returns an array of resources for the given lock
int[]	getSupportedLockScopes(Object resource) Returns array with LockingMechanism.SCOPE_EXCLUSIVE and LockingMechanism.SCOPE_SHARED
protected void	harvestLocks() Removes all locks that are not valid anymore (due to timeout)
boolean	isAccessAllowed(Object resource, String token) Returns true if access to the resource is allowed
boolean	isLocked(Object resource) Returns true if resource is locked
boolean	lockResource(Lock lock, Object resource) Locks reource
protected void	removeLock(Lock lock) Removes a lock
void	removeLocks(Object resource) Removes locks form the given resource
void	setHarvestMinimumInterval(int harvestMinimumInterval) Sets minimal harvest interval in miliseconds
void	unlockResources(Lock lock) Unlocks resource

Methods inherited from class java.lang.Object

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

Field Detail

tokenLocks

protected Map<String,Lock> tokenLocks

Map of tokens to locks

lockResources

protected Map<Lock,Collection<Object>> lockResources

Map of locks to resources

resourcesLocks

protected Map<Object,Collection<Lock>> resourcesLocks

Map of resources to locks

harvestMinimumInterval

protected int harvestMinimumInterval

Minimal interval timed out locks are removed. Defaulted to 10 seconds

nextHarvested

protected long nextHarvested

Time locks can be harvesed as the earliest

Constructor Detail

SimpleInMemoryLockingMechanism

public SimpleInMemoryLockingMechanism()

Constructor

Method Detail

createLock

public Lock createLock(int type,
                       int scope,
                       Object owner,
                       Timeout timeout,
                       int depth)

Creates the lock

Specified by:

createLock in interface LockingMechanism

Parameters:

type - lock type

scope - lock type

owner - lock owner

timeout - lock timeout

depth - lock depth

Returns:

newly created lock

createLockImpl

protected Lock createLockImpl(int type,
                              int scope,
                              Object owner,
                              Timeout timeout,
                              int depth)

Constructs lock object

Parameters:

type - lock type

scope - lock scope

owner - lock owner

timeout - lock timeout

depth - lock depth

Returns:

findLock

public Lock findLock(String token)

Retunrs the lock with the given token or null

Specified by:

findLock in interface LockingMechanism

Parameters:

token - token

Returns:

the lock with the given token or null

lockResource

public boolean lockResource(Lock lock,
                            Object resource)

Locks reource

Specified by:

lockResource in interface LockingMechanism

Parameters:

lock - lock

resource - resource

Returns:

true if lock succeded

unlockResources

public void unlockResources(Lock lock)

Unlocks resource

Specified by:

unlockResources in interface LockingMechanism

Parameters:

lock - lock

removeLocks

public void removeLocks(Object resource)

Removes locks form the given resource

Specified by:

removeLocks in interface LockingMechanism

Parameters:

resource - resource

getLocks

public Lock[] getLocks(Object resource)

Returns locks for the given resource

Specified by:

getLocks in interface LockingMechanism

Parameters:

resource - resource

Returns:

locks array

getResources

public Object[] getResources(Lock lock)

Returns an array of resources for the given lock

Specified by:

getResources in interface LockingMechanism

Parameters:

lock - lock

Returns:

an array of resources

isLocked

public boolean isLocked(Object resource)

Returns true if resource is locked

Specified by:

isLocked in interface LockingMechanism

Parameters:

resource - resource

Returns:

true if resource is locked

isAccessAllowed

public boolean isAccessAllowed(Object resource,
                               String token)

Returns true if access to the resource is allowed

Specified by:

isAccessAllowed in interface LockingMechanism

Parameters:

resource - resource

token - token

Returns:

true if access to the resource is allowed

getSupportedLockScopes

public int[] getSupportedLockScopes(Object resource)

Returns array with LockingMechanism.SCOPE_EXCLUSIVE and LockingMechanism.SCOPE_SHARED

Specified by:

getSupportedLockScopes in interface LockingMechanism

Parameters:

resource - resource

Returns:

array with LockingMechanism.SCOPE_EXCLUSIVE and LockingMechanism.SCOPE_SHARED

harvestLocks

protected void harvestLocks()

Removes all locks that are not valid anymore (due to timeout)

removeLock

protected void removeLock(Lock lock)

Removes a lock

Parameters:

lock - lock

getHarvestMinimumInterval

public int getHarvestMinimumInterval()

Returns minimal harvest interval in miliseconds

Returns:

minimal harvest interval in miliseconds

setHarvestMinimumInterval

public void setHarvestMinimumInterval(int harvestMinimumInterval)

Sets minimal harvest interval in miliseconds