alma.acs.alarmsystem.source

Class AlarmsMap

java.lang.Object

alma.acs.alarmsystem.source.AlarmsMap

public class AlarmsMap
extends java.lang.Object

The map of active and inactive alarms.

Alarms that are not updated after ALARM_ACTIVITY_TIME are removed from the map so that they will be sent again to the alarm service.

The class is thread safe i.e. the methods can be called without any further locking.

Implementation note: All the methods add new entries or update existing pairs in the alarms map with the exception of the periodic thread AlarmsMap.AlarmsMapRunnable.run() that remove elements that are in the map unchanged since more the ALARM_ACTIVITY_TIME.

AlarmsMap does not need any locking because the map contains immutable AlarmsMap.AlarmInfo objects and the map itself is implemented by a ConcurrentHashMap.

Author:

acaproni

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AlarmsMap.AlarmInfo The data stored for each alarm in the map.
class	AlarmsMap.AlarmsMapRunnable The thread to delete the alarms older than the time interval.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ALARM_ACTIVITY_TIME The alarms that have no activity after the following time interval are removed from the map.

Constructor Summary

Constructors

Constructor and Description
AlarmsMap(java.util.concurrent.ThreadFactory threadFactory, java.util.logging.Logger logger) Constructor

Method Summary

Modifier and Type	Method and Description
boolean	clear(java.lang.String alarmID) An alarm has been cleared and must be added to the map.
boolean	containsKey(java.lang.Object key)
AlarmsMap.AlarmInfo	get(java.lang.Object key)
java.util.Collection<java.lang.String>	getActiveAlarms() Return the active alarms in the map
java.util.Set<java.lang.String>	keySet() This method returns a set of the keys in the map at the moment when the method has been called.
boolean	raise(java.lang.String alarmID) An alarms has been raised and must be added to the map.
void	shutdown() Shutdown the thread a frees the resources
int	size() The size of the map
void	start() Start the thread to delete the oldest alarms

Methods inherited from class java.lang.Object

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

Field Detail

ALARM_ACTIVITY_TIME

public static final int ALARM_ACTIVITY_TIME

The alarms that have no activity after the following time interval are removed from the map.

In practice, it means that an alarm with the same state will be sent again if it arrives after ALARM_ACTIVITY_TIME seconds.

See Also:

Constant Field Values

Constructor Detail

AlarmsMap

public AlarmsMap(java.util.concurrent.ThreadFactory threadFactory,
                 java.util.logging.Logger logger)

Constructor

Parameters:

threadFactory - The thread factory to schedule the timer loop

logger - The logger

Method Detail

getActiveAlarms

public java.util.Collection<java.lang.String> getActiveAlarms()

Return the active alarms in the map

Returns:

the active alarms in the map

raise

public boolean raise(java.lang.String alarmID)

An alarms has been raised and must be added to the map.

Parameters:

alarmID - The ID of the alarm

Returns:

true if the alarm with the give ID was already present in the list and it was active; false otherwise.

clear

public boolean clear(java.lang.String alarmID)

An alarm has been cleared and must be added to the map.

Parameters:

alarmID - The ID of the alarm

Returns:

true if the alarm with the give ID was already present in the list and it was terminated; false otherwise.

start

public void start()

Start the thread to delete the oldest alarms

shutdown

public void shutdown()

Shutdown the thread a frees the resources

size

public int size()

The size of the map

Returns:

The size of the map

See Also:

ConcurrentHashMap.size()

containsKey

public boolean containsKey(java.lang.Object key)

Parameters:

key - The key to look for in the map

Returns:

true if the map contains an item with the given ket

get

public AlarmsMap.AlarmInfo get(java.lang.Object key)

Parameters:

key - The key to look for

Returns:

The object with the given key

keySet

public java.util.Set<java.lang.String> keySet()

This method returns a set of the keys in the map at the moment when the method has been called. It is meant to be used for testing purposes only.
Getting elements from the returned set could lead to null values if ssuch a value has been removed by the thread.

Returns:

A set with the key in the map