uk.ac.man.bioinf.apps.systemevents
Interface SystemListener

All Superinterfaces:
EventListener
All Known Implementing Classes:
CinemaCoreGui, InvokerInternalQueue, SaveableOptions

public interface SystemListener
extends EventListener

SystemListener.java Listeners to system events. At the moment this consists of ShutDown events

Created: Thu Jan 14 17:48:54 1999

Compliant:

Version:
Author:
Phillip Lord

Field Summary
static int NO_VETO
          This value should be used when the system is going to shutdown regardless of errors
static int VETO_DUE_TO_ERROR
          This value should be used when the System shutdown can not be aborted unless there is some error in the shutdown procedure
static int VETO_DUE_TO_USER_REQUEST
          This value should be used when the user has full control over aborting the shutdown.
 
Method Summary
 void systemEventOccured(SystemEvent e)
          This is an event listener for system events.
 int systemListenerPriority()
          Some events (particularly shut downs) have to happen in a very specific order.
 

Field Detail

VETO_DUE_TO_ERROR

public static final int VETO_DUE_TO_ERROR
This value should be used when the System shutdown can not be aborted unless there is some error in the shutdown procedure

See Also:
Constant Field Values

VETO_DUE_TO_USER_REQUEST

public static final int VETO_DUE_TO_USER_REQUEST
This value should be used when the user has full control over aborting the shutdown.

See Also:
Constant Field Values

NO_VETO

public static final int NO_VETO
This value should be used when the system is going to shutdown regardless of errors

See Also:
Constant Field Values
Method Detail

systemEventOccured

public void systemEventOccured(SystemEvent e)
                        throws SystemVetoException
This is an event listener for system events. All listeners should be signalled before the SystemEvent occurs. They should not return from this method until they are ready for that event to occur. An exception is thrown if the listener wishes to veto this system event. g

Parameters:
e - the system event occuring
Throws:
SystemVetoException - if the listener does not want the event to happen

systemListenerPriority

public int systemListenerPriority()
Some events (particularly shut downs) have to happen in a very specific order. This method provides a priority to allow this to happen. Those with the lowest priority are informed first. Any valid int value is acceptable. This interface does not provide the ability to set different priorities for different events. The same effect can be achieved by delegating the to a small class. This way a single object can register more than one listener object, and thus have different priorities for different events A listener should not change its priority. There is not guarentee when this value will be used.