Versions Compared

Old Version 7

changes.mady.by.user Felix Meschberger

Saved on

compared with

New Version 8

changes.mady.by.user Richard S. Hall

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
Comment: add short documentation on the management API

...

To simplify the tasks of generating the SCR Desriptor and adding the Service-Component header to the bundle manifest, the Maven SCR Plugin may be used. This helps keeping the descriptor and the code in sync especially during development.

Management

The OSGi Compendium specification defines no management API for Declarative Services. As of version 0.9.0-20071123.131249-8 a simple management API is provided the Apache Felix implementation. The bundle itself also has a Felix Shell Command providing easy commands to introspect the states of the registered components.

Shell Command

The management API is made available to the Felix Shell as the scr command with a short list of subcommands:

Synopsis

Description

scr help [ <subcommand> ]

Show help of the specific <subcommand> or list all known subcommands

scr list [ <bundleId> ]

List registered components of the bundle specified by <bundleId> or list all components. Each component is listed with its component ID, the state and the name

scr info <componentId>

Show a complete information dump of the given component. This dump includes the name, status, provided services and information on the service references

scr enable <componentId>

Enable the given component if not already enabled. If the component is already destroyed or enabled, this command has no effect.

scr disable <componentId>

Disable the given component if not already disabled. If the component is already destroyed or disabled, this command has no effect.

API Use

The API consists of the main interface org.apache.felix.scr.ScrService and two helper interfaces org.apache.felix.scr.Component describing a registered component and org.apache.felix.scr.Reference describing a single reference of a registered component. To access the management API, client applications just ask for the ScrService as usual:

Code Block

....
ServiceReference scrServiceRef = bundleContext.getServiceReference( ScrService.class.getName() );
ScrService scrService = (ScrService) bundleContext.getService(scrServiceRef);
....

Alternatively, you may of course use the ServiceTracker or if you are using the ScrService in a component, you may have the ScrService bound according to the component declaration.

The ScrService allows access to all registered components, to a specific component by component ID or to all registered components of a specific bundle.

Summary

This tutorial just listed some very basic information on Declarative Service. To get more information, for example on hoe the Configuration Admin Service may be used to configure components, refer to the Declarative Services Sepecification in the OSGi Service Platform Service Compendium book.

...