com.ibm.wsspi.kernel.service.utils

Class AtomicServiceReference<T>

  1. java.lang.Object
  2. extended bycom.ibm.wsspi.kernel.service.utils.AtomicServiceReference<T>

  1. public class AtomicServiceReference<T>
  2. extends java.lang.Object
Small class performing atomic operations to find/retrieve/cache the instance of a DeclarativeServices component reference from service registry via the service reference.

Use this to maintain a lazy-resolved reference of cardinality one (single service reference associated with a single, lazily-resolved service instance).

Usage (following OSGi DS naming conventions/patterns):

 private final AtomicServiceReference<T> serviceRef = new AtomicServiceReference<T>("referenceName");
 
 protected void activate(ComponentContext ctx) {
  serviceRef.activate(ctx);
 }
 
 protected void deactivate(ComponentContext ctx) {
  serviceRef.deactivate(ctx);
 }
 
 protected void setReferenceName(ServiceReference<T> ref) {
  serviceRef.setReference(ref);
 }
 
 protected void unsetReferenceName(ServiceReference<T> ref) {
  serviceRef.unsetReference(ref);
 }
 
 private T getReferenceName() {
  return serviceRef.getService();
 }
 

Constructor Summary

Constructor and Description
AtomicServiceReference(java.lang.String name)
Create a new AtomicServiceReference for the named service.

Method Summary

Modifier and Type Method and Description
  1. void
activate(ComponentContext context)
  1. void
deactivate(ComponentContext context)
getReference()
  1. T
getService()
  1. T
getServiceWithException()
  1. boolean
setReference( reference)
Update service reference associated with this service.
  1. java.lang.String
toString()
  1. boolean
unsetReference( reference)
Clear the service reference associated with this service.
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AtomicServiceReference

  1. public AtomicServiceReference(java.lang.String name)
Create a new AtomicServiceReference for the named service. e.g. from bnd.bnd: referenceName=.... or from component.xml:
Parameters:
name - Name of DS reference

Method Detail

activate

  1. public void activate(ComponentContext context)

deactivate

  1. public void deactivate(ComponentContext context)

setReference

  1. public boolean setReference( reference)
Update service reference associated with this service.
Returns:
true if this is replacing a previous (non-null) service reference

unsetReference

  1. public boolean unsetReference( reference)
Clear the service reference associated with this service. This first checks to see whether or not the reference being unset matches the current reference. For Declarative Services dynamic components: if a replacement is available for a dynamic reference, DS will call set with the new reference before calling unset to clear the old one.
Parameters:
reference - ServiceReference associated with service to be unset.
Returns:
true if a non-null value was replaced

getReference

  1. public getReference()
Returns:
ServiceReference for the target service. Service references are equal if they point to the same service registration, and are ordered by increasing service.ranking and decreasing service.id. ServiceReferences hold no service properties: requests/queries for properties are forwarded onto the backing service registration.

getService

  1. public T getService()
Returns:
T or null if unavailable

getServiceWithException

  1. public T getServiceWithException( )
Returns:
T
Throws:
java.lang.IllegalStateException - if the internal state is such that locating the service is not possible or if the service is not retrievable

toString

  1. public java.lang.String toString( )
Overrides:
toString in class java.lang.Object