org.osgi.service.cm

Interface ConfigurationPlugin

public interface ConfigurationPlugin

A service interface for processing configuration dictionary before the update.

A bundle registers a ConfigurationPlugin object in order to process configuration updates before they reach the Managed Service or Managed Service Factory. The Configuration Admin service will detect registrations of Configuration Plugin services and must call these services every time before it calls the ManagedService or ManagedServiceFactory updated method. The Configuration Plugin service thus has the opportunity to view and modify the properties before they are passed to the Managed Service or Managed Service Factory.

Configuration Plugin (plugin) services have full read/write access to all configuration information. Therefore, bundles using this facility should be trusted. Access to this facility should be limited with ServicePermission[ConfigurationPlugin,REGISTER]. Implementations of a Configuration Plugin service should assure that they only act on appropriate configurations.

The Integer service.cmRanking registration property may be specified. Not specifying this registration property, or setting it to something other than an Integer, is the same as setting it to the Integer zero. The service.cmRanking property determines the order in which plugins are invoked. Lower ranked plugins are called before higher ranked ones. In the event of more than one plugin having the same value of service.cmRanking, then the Configuration Admin service arbitrarily chooses the order in which they are called.

By convention, plugins with service.cmRanking< 0 or service.cmRanking > 1000 should not make modifications to the properties.

The Configuration Admin service has the right to hide properties from plugins, or to ignore some or all the changes that they make. This might be done for security reasons. Any such behavior is entirely implementation defined.

A plugin may optionally specify a cm.target registration property whose value is the PID of the Managed Service or Managed Service Factory whose configuration updates the plugin is intended to intercept. The plugin will then only be called with configuration updates that are targeted at the Managed Service or Managed Service Factory with the specified PID. Omitting the cm.target registration property means that the plugin is called for all configuration updates.

Version:

$Revision$

Field Summary

Fields

Modifier and Type	Field and Description
static String	CM_RANKING A service property to specify the order in which plugins are invoked.
static String	CM_TARGET A service property to limit the Managed Service or Managed Service Factory configuration dictionaries a Configuration Plugin service receives.

Method Summary

Methods

Modifier and Type	Method and Description
void	modifyConfiguration(ServiceReference reference, Dictionary properties) View and possibly modify the a set of configuration properties before they are sent to the Managed Service or the Managed Service Factory.

Field Detail

CM_TARGET

static final String CM_TARGET

A service property to limit the Managed Service or Managed Service Factory configuration dictionaries a Configuration Plugin service receives. This property contains a String[] of PIDs. A Configuration Admin service must call a Configuration Plugin service only when this property is not set, or the target service's PID is listed in this property.

See Also:

Constant Field Values

CM_RANKING

static final String CM_RANKING

A service property to specify the order in which plugins are invoked. This property contains an Integer ranking of the plugin. Not specifying this registration property, or setting it to something other than an Integer, is the same as setting it to the Integer zero. This property determines the order in which plugins are invoked. Lower ranked plugins are called before higher ranked ones.

Since:

1.2

See Also:

Constant Field Values

Method Detail

modifyConfiguration

void modifyConfiguration(ServiceReference reference,
                       Dictionary properties)

View and possibly modify the a set of configuration properties before they are sent to the Managed Service or the Managed Service Factory. The Configuration Plugin services are called in increasing order of their service.cmRanking property. If this property is undefined or is a non- Integer type, 0 is used.

This method should not modify the properties unless the service.cmRanking of this plugin is in the range 0 <= service.cmRanking <= 1000.

If this method throws any Exception, the Configuration Admin service must catch it and should log it.

Parameters:

reference - reference to the Managed Service or Managed Service Factory

properties - The configuration properties. This argument must not contain the "service.bundleLocation" property. The value of this property may be obtained from the Configuration.getBundleLocation method.