org.jasig.portal.concurrency.locking
Class ReferenceEntityLockService

java.lang.Object
  org.jasig.portal.concurrency.locking.ReferenceEntityLockService

All Implemented Interfaces:

IEntityLockService

public class ReferenceEntityLockService
extends java.lang.Object
implements IEntityLockService

Version:

$Revision: 1.16 $

Author:

Dan Ellentuck

Field Summary

private int	defaultLockPeriod
private IEntityLockStore	lockStore
private int	lockToleranceMillis
private static org.apache.commons.logging.Log	log
private boolean	multiServer
private static IEntityLockService	singleton

Fields inherited from interface org.jasig.portal.concurrency.IEntityLockService

READ_LOCK, WRITE_LOCK

Constructor Summary

ReferenceEntityLockService()
ReferenceEntityLockingService constructor comment.

Method Summary

void	convert(IEntityLock lock, int newType) Attempts to change the lock's lockType to newType.
void	convert(IEntityLock lock, int newType, int newDuration) Attempts to change the lock's lockType to newType.
boolean	existsInStore(IEntityLock lock) Answer if this IEntityLock exists in the store.
private int	getDefaultLockPeriod()
private IEntityLockStore	getLockStore()
private int	getLockToleranceMillis()
private java.util.Date	getNewExpiration(int durationSecs)
private void	initialize()
private boolean	isLocked(java.lang.Class entityType, java.lang.String entityKey) Answers if the entity represented by the entityType and entityKey already has a lock of some type.
private boolean	isLocked(java.lang.Class entityType, java.lang.String entityKey, java.lang.Integer lockType) Answers if the entity represented by entityType and entityKey has one or more locks.
private boolean	isMultiServer()
private boolean	isUnexpired(IEntityLock lock)
boolean	isValid(IEntityLock lock) Answers if this IEntityLock represents a lock that is still good.
private boolean	isValidLockType(int lockType)
IEntityLock	newLock(java.lang.Class entityType, java.lang.String entityKey, int lockType, java.lang.String owner) Returns a lock for the entity, lock type and owner if no conflicting locks exist.
IEntityLock	newLock(java.lang.Class entityType, java.lang.String entityKey, int lockType, java.lang.String owner, int durationSecs) Returns a lock for the entity, lock type and owner if no conflicting locks exist.
IEntityLock	newLock(EntityIdentifier entityID, int lockType, java.lang.String owner) Returns a lock for the entity, lock type and owner if no conflicting locks exist.
IEntityLock	newLock(EntityIdentifier entityID, int lockType, java.lang.String owner, int durationSecs) Returns a lock for the entity, lock type and owner if no conflicting locks exist.
void	release(IEntityLock lock) Releases the IEntityLock.
void	renew(IEntityLock lock) Extends the expiration time of the lock by some service-defined increment.
void	renew(IEntityLock lock, int duration) Extends the expiration time of the lock by some service-defined increment.
private IEntityLock[]	retrieveLocks(java.lang.Class entityType, java.lang.String entityKey, java.lang.Integer lockType) Returns an IEntityLock[] containing unexpired locks for the entityType, entityKey and lockType.
private void	setDefaultLockPeriod(int newDefaultLockPeriod)
private void	setLockToleranceMillis(int newLockToleranceMillis)
private void	setMultiServer(boolean newMultiServer)
static IEntityLockService	singleton()

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final org.apache.commons.logging.Log log

singleton

private static IEntityLockService singleton

lockStore

private IEntityLockStore lockStore

multiServer

private boolean multiServer

defaultLockPeriod

private int defaultLockPeriod

lockToleranceMillis

private int lockToleranceMillis

Constructor Detail

ReferenceEntityLockService

public ReferenceEntityLockService()
                           throws LockingException

ReferenceEntityLockingService constructor comment.

Throws:

LockingException

Method Detail

convert

public void convert(IEntityLock lock,
                    int newType)
             throws LockingException

Attempts to change the lock's lockType to newType.

Specified by:

convert in interface IEntityLockService

Parameters:

lock - IEntityLock

newType - int

Throws:

LockingException

convert

public void convert(IEntityLock lock,
                    int newType,
                    int newDuration)
             throws LockingException

Attempts to change the lock's lockType to newType.

Specified by:

convert in interface IEntityLockService

Parameters:

lock - IEntityLock

newType - int

newDuration - int

Throws:

LockingException

existsInStore

public boolean existsInStore(IEntityLock lock)
                      throws LockingException

Answer if this IEntityLock exists in the store.

Specified by:

existsInStore in interface IEntityLockService

Parameters:

lock -

Returns:

boolean

Throws:

LockingException

getDefaultLockPeriod

private int getDefaultLockPeriod()

Returns:

int

getLockStore

private IEntityLockStore getLockStore()

Returns:

org.jasig.portal.concurrency.locking.IEntityLockStore

getLockToleranceMillis

private int getLockToleranceMillis()

Returns:

int

getNewExpiration

private java.util.Date getNewExpiration(int durationSecs)

Returns:

java.util.Date

initialize

private void initialize()
                 throws LockingException

Throws:

LockingException

isLocked

private boolean isLocked(java.lang.Class entityType,
                         java.lang.String entityKey)
                  throws LockingException

Answers if the entity represented by the entityType and entityKey already has a lock of some type.

Parameters:

entityType -

entityKey -

Throws:

LockingException

isLocked

private boolean isLocked(java.lang.Class entityType,
                         java.lang.String entityKey,
                         java.lang.Integer lockType)
                  throws LockingException

Answers if the entity represented by entityType and entityKey has one or more locks. Param lockType can be null.

Parameters:

entityType -

entityKey -

lockType - (optional)

Throws:

LockingException

isMultiServer

private boolean isMultiServer()

Returns:

boolean

isUnexpired

private boolean isUnexpired(IEntityLock lock)

Parameters:

lock - IEntityLock

Returns:

boolean

isValid

public boolean isValid(IEntityLock lock)
                throws LockingException

Answers if this IEntityLock represents a lock that is still good. To be valid, a lock must exist in the underlying store and be unexpired.

Specified by:

isValid in interface IEntityLockService

Parameters:

lock - IEntityLock

Throws:

LockingException

isValidLockType

private boolean isValidLockType(int lockType)

newLock

public IEntityLock newLock(java.lang.Class entityType,
                           java.lang.String entityKey,
                           int lockType,
                           java.lang.String owner)
                    throws LockingException

Returns a lock for the entity, lock type and owner if no conflicting locks exist.

Specified by:

newLock in interface IEntityLockService

Parameters:

entityType -

entityKey -

lockType -

owner -

Returns:

org.jasig.portal.groups.IEntityLock

Throws:

LockingException

newLock

public IEntityLock newLock(java.lang.Class entityType,
                           java.lang.String entityKey,
                           int lockType,
                           java.lang.String owner,
                           int durationSecs)
                    throws LockingException

Returns a lock for the entity, lock type and owner if no conflicting locks exist.

Specified by:

newLock in interface IEntityLockService

Parameters:

entityType -

entityKey -

lockType -

owner -

durationSecs -

Returns:

org.jasig.portal.groups.IEntityLock

Throws:

LockingException - Retrieves potentially conflicting locks and checks them before adding the new lock to the store. The add of a write lock will fail if any other lock exists for the entity. The add of a read lock will fail if a write lock exists for the entity. After we add a write lock we check the store a second time and roll back if any other lock has snuck in. I think this is slightly safer than depending on the db isolation level for transactional integrity.

newLock

public IEntityLock newLock(EntityIdentifier entityID,
                           int lockType,
                           java.lang.String owner)
                    throws LockingException

Returns a lock for the entity, lock type and owner if no conflicting locks exist.

Specified by:

newLock in interface IEntityLockService

Parameters:

entityID - org.jasig.portal.EntityIdentifier

lockType - int

owner - String

Returns:

org.jasig.portal.groups.IEntityLock

Throws:

LockingException

newLock

public IEntityLock newLock(EntityIdentifier entityID,
                           int lockType,
                           java.lang.String owner,
                           int durationSecs)
                    throws LockingException

Returns a lock for the entity, lock type and owner if no conflicting locks exist.

Specified by:

newLock in interface IEntityLockService

Parameters:

entityID - org.jasig.portal.EntityIdentifier

lockType - int

owner - String

durationSecs - int

Returns:

org.jasig.portal.groups.IEntityLock

Throws:

LockingException

release

public void release(IEntityLock lock)
             throws LockingException

Releases the IEntityLock.

Specified by:

release in interface IEntityLockService

Parameters:

lock - IEntityLock

Throws:

LockingException

renew

public void renew(IEntityLock lock)
           throws LockingException

Extends the expiration time of the lock by some service-defined increment.

Specified by:

renew in interface IEntityLockService

Parameters:

lock - IEntityLock

Throws:

LockingException

renew

public void renew(IEntityLock lock,
                  int duration)
           throws LockingException

Extends the expiration time of the lock by some service-defined increment.

Specified by:

renew in interface IEntityLockService

Parameters:

lock - IEntityLock

Throws:

LockingException

retrieveLocks

private IEntityLock[] retrieveLocks(java.lang.Class entityType,
                                    java.lang.String entityKey,
                                    java.lang.Integer lockType)
                             throws LockingException

Returns an IEntityLock[] containing unexpired locks for the entityType, entityKey and lockType. Param lockType can be null.

Parameters:

entityType -

entityKey -

lockType - (optional)

Throws:

LockingException

setDefaultLockPeriod

private void setDefaultLockPeriod(int newDefaultLockPeriod)

Parameters:

newDefaultLockPeriod - int

setLockToleranceMillis

private void setLockToleranceMillis(int newLockToleranceMillis)

Parameters:

newLockToleranceMillis - int

setMultiServer

private void setMultiServer(boolean newMultiServer)

Parameters:

newMultiServer - boolean

singleton

public static IEntityLockService singleton()
                                    throws LockingException

Returns:

org.jasig.portal.concurrency.locking.ReferenceEntityLockService

Throws:

LockingException