com.cosylab.acs.laser.dao

Class ACSAlarmCacheImpl

java.lang.Object

com.cosylab.acs.laser.dao.ACSAlarmCacheImpl

All Implemented Interfaces:

AlarmCache

public class ACSAlarmCacheImpl
extends java.lang.Object
implements AlarmCache

Implementation of the AlarmCache to use within ACS.

Note on the locking mechanism.
Each method that changes or reads the cache is surrounded by lock/unlock to ensure the mutual exclusion and therefore the integrity of the cache. If a sequence of operations have to be performed in mutual exclusion then the code must initially call acquire() and finally release(). The locking mechanism of each method works as follows:

• if the lock is free then it is acquired at the beginning and released before exiting
• if the lock is not free then it is acquired only if owned by the same thread that is locking it and released before exiting

Author:

acaproni

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	alarmServerPropkey The key of the property for undocumented alarms
static java.lang.String	undocumentedAlarmProp The value of the property for undocumented alarms

Constructor Summary

Constructors

Constructor and Description
ACSAlarmCacheImpl(AlarmDAO alarmDAO, ACSCategoryDAOImpl categoryDAO, AlarmCacheListener alarmCacheListener, java.util.logging.Logger logger) The constructor

Method Summary

Modifier and Type	Method and Description
void	acquire() Acquire the lock for using the cache.
void	close() Close and deallocate the resources.
CategoryActiveList	getActiveListReference(java.lang.Integer identifier) Returns a reference to the active list for a category.
Alarm	getCopy(java.lang.String identifier) Returns a clone of the cached alarm.
Alarm	getReference(java.lang.String identifier) Get a reference to the alarm with the passed identifier.
void	initializeAlarmCache(java.util.Map alarms, java.util.Map activeLists) Initializes the alarm cache.
void	invalidate(java.lang.String identifier) Invalidate the cached object.
void	put(Alarm alarm) Puts an object in the cache.
void	release() Acquire the lock for using the cache.
void	removeActiveList(java.lang.Integer identifier) Remove the active list associated with the given category id.
void	replace(Alarm alarm) Puts alarm in the cache.
void	update(Alarm alarm) Update an alarm in the cache without notifying the listener.

Methods inherited from class java.lang.Object

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

Field Detail

alarmServerPropkey

public static final java.lang.String alarmServerPropkey

The key of the property for undocumented alarms

See Also:

Constant Field Values

undocumentedAlarmProp

public static final java.lang.String undocumentedAlarmProp

The value of the property for undocumented alarms

See Also:

Constant Field Values

Constructor Detail

ACSAlarmCacheImpl

public ACSAlarmCacheImpl(AlarmDAO alarmDAO,
                         ACSCategoryDAOImpl categoryDAO,
                         AlarmCacheListener alarmCacheListener,
                         java.util.logging.Logger logger)

The constructor

Parameters:

alarmDAO - The object to access the database

alarmCacheListener - The listener

Method Detail

initializeAlarmCache

public void initializeAlarmCache(java.util.Map alarms,
                                 java.util.Map activeLists)

Description copied from interface: AlarmCache

Initializes the alarm cache. Can only be called once.

Specified by:

initializeAlarmCache in interface AlarmCache

getCopy

public Alarm getCopy(java.lang.String identifier)
              throws AlarmCacheException

Description copied from interface: AlarmCache

Returns a clone of the cached alarm.

Specified by:

getCopy in interface AlarmCache

Parameters:

identifier - the alarm private identifier

Returns:

the cloned alarm object.

Throws:

AlarmCacheException

getReference

public Alarm getReference(java.lang.String identifier)
                   throws AlarmCacheException

Get a reference to the alarm with the passed identifier. The alarm is searched in the configuration database delegating to the ACSAlarmDAOImpl.

If the alarm is not found then an alarm is built to be sent to the client but it is marked with a special property to identify it as a misconfigured alarm. In the case of the alarm panel, such alarms will be displayed in a dedicated tab.

Specified by:

getReference in interface AlarmCache

Parameters:

identifier - The ID of the alarm to get from the cache

Returns:

the reference to the alarm object

Throws:

AlarmCacheException - if the operation cannot be performed

update

public void update(Alarm alarm)

Update an alarm in the cache without notifying the listener. NOTE: this is used when alarms are generated on the fly (defaultFM) because in that case there i sno need to notify the listener

Parameters:

alarm -

replace

public void replace(Alarm alarm)
             throws AlarmCacheException

Description copied from interface: AlarmCache

Puts alarm in the cache. This method must be called after @link acquire as the alarm need to be locked.

Specified by:

replace in interface AlarmCache

Parameters:

alarm - object to put in cache

Throws:

AlarmCacheException - if the operation cannot be performed. However, the lock is released.

put

public void put(Alarm alarm)
         throws AlarmCacheException

Description copied from interface: AlarmCache

Puts an object in the cache. If that object was already in the cache it is replaced. This method combines the methods @link acquire, @link replace, and @link release

Specified by:

put in interface AlarmCache

Parameters:

alarm - the new alarm object

Throws:

AlarmCacheException

invalidate

public void invalidate(java.lang.String identifier)
                throws AlarmCacheException

Description copied from interface: AlarmCache

Invalidate the cached object. Subsequent accesses to that object will cause the object to be loaded again from the ejb.

Specified by:

invalidate in interface AlarmCache

Parameters:

identifier - the alarm private identifier

Throws:

AlarmCacheException

getActiveListReference

public CategoryActiveList getActiveListReference(java.lang.Integer identifier)
                                          throws AlarmCacheException

Description copied from interface: AlarmCache

Returns a reference to the active list for a category.

Specified by:

getActiveListReference in interface AlarmCache

Parameters:

identifier - the active list private identifier

Returns:

the reference to the active list object.

Throws:

AlarmCacheException

close

public void close()

Description copied from interface: AlarmCache

Close and deallocate the resources.

Specified by:

close in interface AlarmCache

removeActiveList

public void removeActiveList(java.lang.Integer identifier)
                      throws AlarmCacheException

Description copied from interface: AlarmCache

Remove the active list associated with the given category id.

Specified by:

removeActiveList in interface AlarmCache

Parameters:

identifier - the id of the active list to destroy (=category id)

Throws:

AlarmCacheException

acquire

public void acquire()

Acquire the lock for using the cache.

release

public void release()

Acquire the lock for using the cache.