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Table of Contents
Super Watchdog is the twin software of Super Scheduler, which is timer-action job scheduler. This document specifies the main differences between Super Scheduler and Super Watchdog only. Please read Super Scheduler for more information.
In this document, the term trigger and event are interchangeable. The same is true for action and task.
Main Features
There are three Watchdog modes: Doer, Talker and Daemon. It is similar to Scheduler Mode of Super Scheduler.
A task is the action object with one target job and one trigger object. A task will be executed once when it is triggered.
Note: a Task of Super Scheduler is similar with a Task of Super Watchdog. But they are different: the scheduled terms are different. The scheduled term of Super Scheduler is by timing, while the scheduled term of Super Watchdog is by event.
The status of the task is about the nature of the task. A task can have the following statuses:
A task will never be triggered if its status is not Standby. Non-active tasks can still be run manually. Non-active tasks may be run programmatically or as a member of a composite task (Sequence, Retry or Workflow task).
A working task is a mirror version of the original task for one execution only. A working task is created and maintained during the execution of a task.
The status of the working task is about the execution of the task. A working task have the following statuses:
The trigger is the event object which starts the task.
The Effective period allows you to set an active period: From and To for a task.
The format of summary information about trigger is:
TriggerObject; delay; Start-Period; End-Period
Some parts of them may be empty if they are not defined.
The period is the effective period for a task: A task will not be triggered out of its period.
A task can be suspended and activated at any time you want. A suspended task will never be triggered. A suspended task can be manually run immediately.
If the status of a task is Suspended or Error, it can be reactivated by re-save it. Or click the Activate button on the SuperScheduler panel.
A reactivated task will consume all existing trigger conditions. In other words, the existing trigger conditions will not trigger the task at its reactivation time.
Super Watchdog share the same task database with Super Scheduler. Please see Task database of Super Scheduler for more information.
At the time a event is triggered, there may be some existing conditions which may trigger new added tasks immediately. SuperWatchdog automatically consume these existing conditions, so a new added or activated task will be triggered by upcoming conditions only.
You can run the Watchdog scheduling engine as a command line daemon under <Acelet-Scheduler Home>, the default directory is acelet-scheduler. You need to run scripts. These scripts set required environment variables for using some jar files.
You can do either of the followings:
On Unix:
> cd acelet-scheduler
> sh runSuperWatchdoggingDaemon.sh
On Windows:
> cd acelet-scheduler
> runSuperWatchdoggingDaemon.bat
To run SuperWatchdog command line daemon you still need a full installation of Acelet-Scheduler. When the command line executor starts, it uses parameters stored in properties files to connect to server and databases. The files and property values are:
beanbox/scheduler.properties, for task database connection:taskDatabaseUserName taskDatabasePassword
Note: Super Watchdog and Super Scheduler share the same task database.
If you use J2EE related modules, you also need the following file and property values:
super.properties, for application server connection:
serverLoginName serverPassword
These parameters are stored as plain text. If you have security concerns, do not save them. When the command line executor starts, it tries to connect to the database. If the connection fail, it will prompt message and ask you to key in user names and passwords. See ../scheduler/SuperScheduler.html#Security for more information.
To shutdown the command line executor, you need to use facilities from the operating system, such as Control-c, kill (Unix) or Task Manager (Windows). See ../scheduler/SuperScheduler.html#Graceful and forceful shutdown for related information.
User defined triggers must implement com.acelet.s.watchdog.Triggering.
See ExampleUserTriggering as an example.
Register MBean notification when the MBean does not exist
You may in a situation when you want start an MBean triggered task when the MBean does not exist or has been stopped. This issue has not be addressed by JMX specification. SuperWatchdog uses vender specific feature to make the registration of future-able, so the registration of a trigger of MBean notification will not generate error. When the MBean is up and running, the trigger is working. This feature is supported for following application servers: