<resin:ScheduledTask> schedules a job to be executed at specific times
or after specific delays. The times can be specified by a cron syntax or
by a simple delay parameter. The job can be either a Runnable
bean, a method specified by an EL expression, or a URL.
When specified as an Java Injection bean, the bean task
has full IoC capabilities,
including injection, @TransactionAttribute aspects, interception and
@Observes.
| Attribute |
Description |
| class |
the classname of the singleton bean to create |
| cron |
a cron-style scheduling description |
| delay |
a simple delay-based execution |
| init |
IoC initialization for the bean |
| mbean-name |
optional MBean name for JMX registration |
| method |
EL expression for a method to be invoked as the task |
| name |
optional IoC name for registering the task |
| period |
how often the task should be invoked in simple mode |
| task |
alternate task assignment for predefined beans |
The most common and flexible job configuration uses standard IoC
bean-style configuration. The bean must implement Runnable.
The <task> element specifies the bean, using standard
Java injection syntax as described
in Java Injection configuration.
<web-app xmlns="http://caucho.com/ns/resin"
xmlns:resin="urn:java:com.caucho.resin">
<resin:ScheduledTask>
<cron>*/5</cron>
<task>
<qa:MyTask xmlns:qa="urn:java:com.caucho.resin"/>
</task>
</ScheduledTask>
</web-app>
The task bean can also be passed to the <scheduled-task> using
a Resin-IoC EL reference. The name of the task bean would be defined
previously, either in a <bean> or <component> or picked up by classpath
scanning. Like the bean-style job configuration, the reference bean must
implement Runnable.
<web-app xmlns="http://caucho.com/ns/resin"
xmlns:resin="urn:java:com.caucho.resin">
<resin:ScheduledTask task="#{taskBean}">
<cron>0 0 *</cron>
</resin:ScheduledTask>
</web-app>
<scheduled-task> can execute a method on a defined bean as the
scheduler's task. The method is specified using EL reference syntax.
At each trigger time, <scheduled-task> will invoke the EL method
expression.
In the following example, the task invokes myMethod()
on the myBean singleton every 1 hour.
<web-app xmlns="http://caucho.com/ns/resin"
xmlns:resin="urn:java:com.caucho.resin"
xmlns:qa="urn:java:qa">
<qa:MyBean>
<Named>myBean</Named>
</qa:MyBean>
<resin:ScheduledTask method="#{myBean.myMethod}">
<resin:delay>10m</resin:delay>
<resin:period>1h</resin:period>
</resin:ScheduledTask>
</web-app>
In a <web-app>, the <scheduled-task> can invoke a servlet URL
at the trigger times. The task uses the servlet RequestDispatcher
and forwards to the specified URL. The URL is relative to the <web-app>
which contains the <scheduled-task.
<web-app xmlns="http://caucho.com/ns/resin"
xmlns:resin="urn:java:com.caucho.config">
<resin:ScheduledTask url="/cron.php">
<resin:cron>0 15 * * 0</resin:cron>
</resin:ScheduledTask>
</web-app>
Some ascii art from the wikipedia
cron entry
# +---------------- minute (0 - 59)
# | +------------- hour (0 - 23)
# | | +---------- day of month (1 - 31)
# | | | +------- month (1 - 12)
# | | | | +---- day of week (0 - 6) (Sunday=0 or 7)
# | | | | |
* * * * *
| Pattern |
Description |
| * |
matches all time periods |
| 15 |
matches the specific time, e.g. 15 for minutes |
| 15,45 |
matches a list of times, e.g. every :15 and :45 |
| */5 |
matches every n times, e.g. every 5 minutes |
| 1-5 |
matches a range of times, e.g. mon, tue, wed, thu, fri (1-5) |
Each field specifies a range of times to be executed. The patterns
allowed are:
| range |
explanation (using minutes as example) |
| * |
run every minute |
| */5 |
run every 5 minutes |
| 0,5,50 |
run at :00, :05, :50 every hour |
| 0-4 |
run at :00, :01, :02, :03, :04 |
| 0-30/2 |
run every 2 minutes for the first half hour |
The minutes field is always required, and the hours, days, and
months fields are optional.
| range |
explanation |
| 0 */3 |
run every 3 hours |
| 15 2 * |
run every day at 0215 local time |
| 0 0 */3 |
run every third day at midnight |
| 15 0 * * 6 |
run every Saturday at 0015 |