com.eurotech.framework.configuration

Interface ConfigurationService

public interface ConfigurationService

The Configuration Service is used to manage the configuration of ConfigurableComponents. It works in concert with the OSGi ConfigurationAdmin and the OSGi MetaTypeService services. What it provides over the native OSGi services is the ability to easily access the current configuration of a ConfigurableComponent together with its full ObjectClassDefintion, the ability to take snapshots of the current configuration of all registered ConfigurableComponents or rollback to older snapshots and, finally, the ability to access and manage configurations remotely through the CloudService.
The Configuration Service operates on a subset of all the Components registered under the OSGi container. It tracks all OSGi Components which implement the ConfigurableComponent marker interface. When a ConfigurableComponent is registered, the Configuration Service will call its "update" method with the latest saved configuration as returned the ConfigurationAdmin or, if none is available, with the Configuration properties fabricated from the default attribute values as specified in the ObjectClassDefinition of this service. In OSGi terms, this process in similar to the Auto Configuration Service. The ConfigurationService assumes that Meta Type Information XML resource for a given Declarative Service with name abc" to be stored under OSGI-INF/metatype/abc.xml. This is an extra restriction over the OSGi specification: the Meta Type Information XML resource must be named as the name of the Declarative Service Component.
The ConfigurationService has the ability to create a snapshot for the current configuration of all the registered ConfigurableComponents. The snapshot is saved in the form of an XML file stored under $EsfHome/snapshots/snapshot_epoch.xml where epoch is replaced with the epoch timestamp at the time of the snapshot creation. The ConfigurationService also has the ability to rollback the configuration of the registered components taking them back to a previous stored snapshot.
The ConfigurationService interacts with the CloudService to allow to access current configuration and to modify it remotely through messages sent and received via cloud.

Method Summary

Methods

Modifier and Type	Method and Description
ComponentConfiguration	getComponentConfiguration(String pid) Returns the ComponentConfiguration for the component identified with specified PID (service's persistent identity).
List<ComponentConfiguration>	getComponentConfigurations() Returns the list of ConfigurableComponents currently registered with the ConfigurationService.
Set<String>	getConfigurableComponentPids() Return the PIDs (service's persistent identity) for all the services that implements the ConfigurableComponent Maker interface and registered themselves with the container.
List<ComponentConfiguration>	getSnapshot(long sid) Loads a snapshot given its ID and return the component configurations stored in that snapshot.
Set<Long>	getSnapshots() Returns the ID of all the snapshots taken by the ConfigurationService.
long	rollback() Rolls back to the last saved snapshot if available.
void	rollback(long id) Rolls back to the specified snapshot id.
long	snapshot() Takes a new snapshot of the current configuration of all the registered ConfigurableCompoenents.
void	updateConfiguration(String pid, Map<String,Object> properties) Updates the Configuration of the registered component with the specified pid.
void	updateConfigurations(List<ComponentConfiguration> configs)

Method Detail

getConfigurableComponentPids

Set<String> getConfigurableComponentPids()

Return the PIDs (service's persistent identity) for all the services that implements the ConfigurableComponent Maker interface and registered themselves with the container. The service's persistent identity is defined as the name attribute of the Component Descriptor XML file; at runtime, the same value is also available in the component.name and in the service.pid attributes of the Component Configuration.

Returns:

list of PIDs for registered ConfigurableComponents

getComponentConfigurations

List<ComponentConfiguration> getComponentConfigurations()
                                                        throws EsfException

Returns the list of ConfigurableComponents currently registered with the ConfigurationService.

Returns:

list of registered ConfigurableComponents

Throws:

EsfException

getComponentConfiguration

ComponentConfiguration getComponentConfiguration(String pid)
                                                 throws EsfException

Returns the ComponentConfiguration for the component identified with specified PID (service's persistent identity). The service's persistent identity is defined as the name attribute of the Component Descriptor XML file; at runtime, the same value is also available in the component.name and in the service.pid attributes of the Component Configuration.

Parameters:

pid - The ID of the component whose configuration is requested.

Returns:

ComponentConfiguration of the requested Component.

Throws:

EsfException

updateConfiguration

void updateConfiguration(String pid,
                       Map<String,Object> properties)
                         throws EsfException

Updates the Configuration of the registered component with the specified pid. Using the OSGi ConfigurationAdmin, it retrieves the Configuration of the component with the specified PID and then send an update using the specified properties.
If the component to be updated is not yet registered with the ConfigurationService, it is first registered and then it is updated with the specified properties. Before updating the component, the specified properties are validated against the ObjectClassDefinition associated to the Component. The Configuration Service is fully compliant with the OSGi MetaType Information and the validation happens through the OSGi MetaType Service.
The Configuration Service is compliant with the OSGi MetaType Service so it accepts all attribute types defined in the OSGi Compendium Specifications.
it accepts all

Parameters:

pid - The ID of the component whose configuration is requested.

properties - Properties to be used as the new Configuration for the specified Component.

Throws:

EsfException - if the properties specified do not pass the validation of the ObjectClassDefinition

updateConfigurations

void updateConfigurations(List<ComponentConfiguration> configs)
                          throws EsfException

Throws:

EsfException

getSnapshots

Set<Long> getSnapshots()
                       throws EsfException

Returns the ID of all the snapshots taken by the ConfigurationService. The snapshot ID is the epoch time at which the snapshot was taken. The snapshots are stored in the EsfHome/snapshots/ directory. This API will return all the snpashot files available in that location.

Returns:

IDs of the snapshots available.

Throws:

EsfException

getSnapshot

List<ComponentConfiguration> getSnapshot(long sid)
                                         throws EsfException

Loads a snapshot given its ID and return the component configurations stored in that snapshot.

Parameters:

sid - - ID of the snapshot to be loaded

Returns:

List of ComponentConfigurations contained in the snapshot

Throws:

EsfException

snapshot

long snapshot()
              throws EsfException

Takes a new snapshot of the current configuration of all the registered ConfigurableCompoenents. It returns the ID of a snapshot as the epoch time at which the snapshot was taken.

Returns:

the ID of the snapshot.

Throws:

EsfException

rollback

long rollback()
              throws EsfException

Rolls back to the last saved snapshot if available.

Returns:

the ID of the snapshot it rolled back to

Throws:

EsfException - if no snapshots are available or

rollback

void rollback(long id)
              throws EsfException

Rolls back to the specified snapshot id.

Parameters:

id - ID of the snapshot we need to rollback to

Throws:

EsfException - if the snapshot is not found