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OSGi™ Service Platform Release 2 |
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Manage multiple service instances. Bundles registering this interface are giving the Configuration Admin service the ability to create and configure a number of instances of a service that the implementing bundle can provide. For example, a bundle implementing a DHCP server could be instantiated multiple times for different interfaces using a factory.
Each of these service instances is represented, in the persistent storage of the Configuration Admin service, by a factory Configuration object that has a PID. When such a Configuration is updated, the Configuration Admin service calls the ManagedServiceFactory updated method with the new properties. When updated is called with a new PID, the Managed Service Factory should create a new factory instance based on these configuration properties. When called with a PID that it has seen before, it should update that existing service instance with the new configuration information.
In general it is expected that the implementation of this interface will maintain a data structure that maps PIDs to the factory instances that it has created. The semantics of a a factory instance are defined by the Managed Service Factory. However, if the factory instance is registered as a service object with the service registry, its PID should match the PID of the corresponding Configuration object.
An example that demonstrates the use of a factory. It will create serial ports under command of the Configuration Admin service.
class SerialPortFactory implements ManagedServiceFactory { ServiceRegistration registration; Hashtable ports; void start(BundleContext context) { Hashtable properties = new Hashtable(); properties.put( Constants.SERVICE_PID, "com.acme.serialportfactory" ); registration = context.registerService( ManagedService.class.getName(), this, properties ); } public void updated( String pid, Dictionary properties ) { String portName = (String) properties.get("port"); SerialPortService port = (SerialPort) ports.get( pid ); if ( port == null ) { port = new SerialPortService(); ports.put( pid, port ); port.open(); } if ( port.getPortName().equals(portName) ) return; port.setPortName( portName ); } public void deleted( String pid ) { SerialPortService port = (SerialPort) ports.get( pid ); port.close(); ports.remove( pid ); } ... }
Method Summary | |
void |
deleted(java.lang.String pid)
Remove a factory instance. |
java.lang.String |
getName()
Return a descriptive name of this factory. |
void |
updated(java.lang.String pid,
java.util.Dictionary properties)
Create a new instance, or update the configuration of an existing instance. |
Method Detail |
public java.lang.String getName()
public void updated(java.lang.String pid, java.util.Dictionary properties) throws ConfigurationException
If the factory instance is registered with the Framework, then the configuration properties should be copied to its registry properties. This is not mandatory and security sensitive properties should obviously not be copied.
If this method throws any Exception, the Configuration Admin service must catch it and should log it.
When the implementation of updated detects any kind of error in the configuration properties, it should create a new which describes the problem.
The Configuration Admin service must call this method on a thread other than the thread which necessitated the callback. This implies that implementors of the ManagedServiceFactory class can be assured that the callback will not take place during registration when they execute the registration in a synchronized method.
pid
- the PID for this configurationproperties
- the configuration properties
ConfigurationException
- when the configuration properties are invalidpublic void deleted(java.lang.String pid)
If this method throws any Exception, the Configuration Admin service must catch it and should log it.
The Configuration Admin service must call this method on a thread other than the thread which called delete() on the corresponding Configuration object.
pid
- the PID of the service to be removed
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OSGi™ Service Platform Release 2 |
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