org.deegree.feature.persistence.lock
Class DefaultLockManager

java.lang.Object
  org.deegree.feature.persistence.lock.DefaultLockManager

All Implemented Interfaces:

LockManager

public class DefaultLockManager
extends Object
implements LockManager

LockManager implementation that is based on an SQL database.

TODO Currently this class is only tested with Derby 10, but it should be easy to make it work with PostGIS, Oracle and other SQL DBs.

Version:

$Revision: 21300 $, $Date: 2009-12-07 22:38:20 +0100 (Mo, 07 Dez 2009) $

Author:

Markus Schneider, last edited by: $Author: mschneider $

Constructor Summary

DefaultLockManager(FeatureStore store, String jdbcConnId)
Creates a new DefaultLockManager for the given FeatureStore.

Method Summary

Lock	acquireLock(LockOperation[] lockRequests, boolean mustLockAll, long expireTimeout) Acquires a lock for the specified features instances.
CloseableIterator<Lock>	getActiveLocks() Returns all active locks.
Lock	getLock(String lockId) Returns the active lock with the given id.
(package private) FeatureStore	getStore() Returns the associated FeatureStore.
boolean	isFeatureLocked(String fid) Returns whether an active lock on the specified feature exists.
boolean	isFeatureModifiable(String fid, String lockId) Returns whether the specified feature is modifiable for the owner of the specified lock.
(package private) void	releaseExpiredLocks() Checks for and releases all expired locks.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultLockManager

public DefaultLockManager(FeatureStore store,
                          String jdbcConnId)
                   throws FeatureStoreException

Creates a new DefaultLockManager for the given FeatureStore.

Parameters:

store -

jdbcConnId -

Throws:

FeatureStoreException - if the initialization of the locking backend fails

Method Detail

getStore

FeatureStore getStore()

Returns the associated FeatureStore.

Returns:

the associated store, never null

acquireLock

public Lock acquireLock(LockOperation[] lockRequests,
                        boolean mustLockAll,
                        long expireTimeout)
                 throws FeatureStoreException

Description copied from interface: LockManager

Acquires a lock for the specified features instances.

If mustLockAll is true and not all of the specified features can be locked, a FeatureStoreException is thrown.

If no features have been locked at all, a lock will be issued, but the lock is not registered (as requested by the WFS spec.).

Specified by:

acquireLock in interface LockManager

Parameters:

lockRequests - lock requests to be executed, must not be null

mustLockAll - if true, a FeatureStoreException is thrown if any of the requested feature instances could not be locked

expireTimeout - number of milliseconds before the lock is automatically released

Returns:

lock identifier, never null

Throws:

FeatureStoreException - if an internal error occurs or if mustLockAll is true and at least one feature could not be locked

getActiveLocks

public CloseableIterator<Lock> getActiveLocks()

Description copied from interface: LockManager

Returns all active locks.

NOTE: The caller must invoke CloseableIterator.close() after it's not needed anymore -- otherwise, backing resources (such as database connections) may not be freed.

Specified by:

getActiveLocks in interface LockManager

Returns:

an iterator for all locks

getLock

public Lock getLock(String lockId)
             throws FeatureStoreException

Description copied from interface: LockManager

Returns the active lock with the given id.

Specified by:

getLock in interface LockManager

Returns:

the active lock with the given id

Throws:

FeatureStoreException

isFeatureLocked

public boolean isFeatureLocked(String fid)
                        throws FeatureStoreException

Description copied from interface: LockManager

Returns whether an active lock on the specified feature exists.

Specified by:

isFeatureLocked in interface LockManager

Parameters:

fid - id of the feature

Returns:

true, if an active lock on the feature exists, false otherwise

Throws:

FeatureStoreException

isFeatureModifiable

public boolean isFeatureModifiable(String fid,
                                   String lockId)
                            throws FeatureStoreException

Description copied from interface: LockManager

Returns whether the specified feature is modifiable for the owner of the specified lock.

Specified by:

isFeatureModifiable in interface LockManager

Parameters:

fid - id of the feature, must not be null

lockId - if of the lock, may be null (in this case the feature is only modifiable if the feature is not locked at all)

Returns:

true, if the feature is not locked at all or the specified lock matches the feature's lock, false otherwise

Throws:

FeatureStoreException

releaseExpiredLocks

void releaseExpiredLocks()

Checks for and releases all expired locks.