JRun SDK Guide
JRun Services

Service architecture (JMX)

Services are the atomic unit of a JRun server, and all feature components must contain a service view-whether that view is a wrapper, a helper class, a factory, or the functional class itself-in order to be plugged into JRun. All JRun components, even the bootstrap components that manage the JMX spine, are services.

Each service, regardless of its vertical functional purpose, participates in the following lifecycle stages:

• init  Lets you establish values for nonmanaged instance variables.
• start  Binds the service to JNDI and prepares it for use.
• stop  Removes the service from JNDI and it becomes unusable, although still resident in memory and capable of quickly being restarted.
• destroy  Disposes of the service's resources, the service itself is removed from memory.

When the JRun server starts, services that are externalized as XML entries in jrun.xml are automatically created, initialized, and started, and their attributes are automatically configured. The services are automatically stopped and destroyed when the JRun server shuts down. You can invoke the start and stop methods any number of times on a running server in order to restart a service. The following list contains more detail on the service lifecycle:

1. All services are created and their attributes set in the order in which their entries appear in jrun.xml.
2. All services have their init methods invoked, based on the order in which the services appear in jrun.xml.
3. All services have their start methods invoked, based on the order in which the services appear in jrun.xml. Each service whose bindToJNDI attribute is set to true is bound to JNDI.
4. On receipt of a shutdown event, all services have their stop methods invoked in reverse order in which they appear in jrun.xml, and JNDI-enabled services are removed from JNDI.
5. All services have their destroy methods invoked in reverse order in which they appear in jrun.xml.

The following figure shows the JRun service class architecture:

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Current page: http://livedocs.adobe.com/jrun/4/JRun_SDK_Guide/creatingservices2.htm

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