| This component removes
Deletable blackboard objects
according to policy and their age.
How to Configure the DeletionPlugin:
The DeletionPlugin runs according to a prescribed schedule to find
Deletable objects on the blackboard and delete them if they are ready
to be deleted. These actions are controlled by a
DelectionSchedulePolicy and one or more DeletionPolicy objects on the
blackboard. The DeletionPlugin guarantees that there is always a
DefaultDeletionPolicy present by creating on at startup (or restart)
if there is not one already present.
DeletionSchedulePolicy:
The deletion schedule is characterized primarily by a period (how
often) and a phase (at what time of day). The public interface of the
standard DeletionSchedulePolicy allows all aspects of the schedule to
be altered including adding specific times for deletion to occur. The
current DeletionPlugin implementation insures that exactly one
DeletionSchedulePolicy exists on the blackboard creating one if
necessary and deleting extraneous ones. If an existing policy is
found, it is left as is. Subclasses could choose to insure that the
periodic schedule parameters agree with the values specified as plugin
parameters.
DefaultDeletionPolicy:
The DeletionPlugin also guarantees that there is exactly one default
DeletionPolicy on the blackboard. If there are none, one is created
using plugin parameters. If there are multiples (should never happen),
extras are deleted.
DeletionPlugin Parameters:
The DeletionPlug accepts four named parameters as follows:
deletionDelay=<long default 15 days>
deletionPeriod=<long default 7 days>
deletionPhase=<long 0 (midnight)>
archivingEnabled=<boolean>
The archivingEnable parameter causes a persistence snapshot to be
taken for archiving purposes prior to doing deletions.
| 