com.ibm.wsspi.kernel.service.utils
Class ConcurrentServiceReferenceMap<K,V>

java.lang.Object
  extended by com.ibm.wsspi.kernel.service.utils.ConcurrentServiceReferenceMap<K,V>

public class ConcurrentServiceReferenceMap<K,V>
extends java.lang.Object

This provides a simple map implementation for lazy-resolution of services. Use this class when you have frequent retrieval with infrequent add/removal. Entries are not stored in any particular order.

Usage (following OSGi DS naming conventions/patterns):

 private final ConcurrentServiceReferenceMap<K,V> serviceMap = new ConcurrentServiceReferenceMap<K,V>("referenceName");
 
 protected void activate(ComponentContext ctx) {
  serviceMap.activate(ctx);
 }
 
 protected void deactivate(ComponentContext ctx) {
  serviceMap.deactivate(ctx);
 }
 
 protected void setReferenceName(ServiceReference<V> ref) {
  K key;
  serviceMap.addReference(key, ref);
 }
 
 protected void unsetReferenceName(ServiceReference<V> ref) {
  K key;
  serviceMap.removeReference(key, ref);
 }
 
 public ServiceReference<V> getReferenceName(K key) {
  return serviceMap.getServices(key);
 }
 


Constructor Summary
ConcurrentServiceReferenceMap(java.lang.String name)
          Create a new ConcurrentServiceReferenceMap for the named service.
 
Method Summary
 void activate(org.osgi.service.component.ComponentContext context)
           
 void deactivate(org.osgi.service.component.ComponentContext context)
          Deactivates the map.
 org.osgi.framework.ServiceReference<V> getReference(K key)
          Returns the ServiceReference associated with key
 V getService(K key)
          Retrieve the service associated with key.
 java.util.Iterator<V> getServices()
          Iterate over all services in the map in no specific order.
 V getServiceWithException(K key)
           
 boolean isEmpty()
          Check if there are any registered/added service references: this will return true if the set is empty (none available).
 java.util.Set<K> keySet()
          Answers a Set of the keys contained in this Map in no specific order.
 boolean putReference(K key, org.osgi.framework.ServiceReference<V> reference)
          Associates the reference with the key.
 org.osgi.framework.ServiceReference<V> putReferenceIfAbsent(K key, org.osgi.framework.ServiceReference<V> reference)
          Associates the reference with the key but only if there is not an existing reference associated with that key.
 java.lang.Iterable<org.osgi.framework.ServiceReference<V>> references()
           
 boolean removeReference(K key, org.osgi.framework.ServiceReference<V> reference)
          Removes the reference associated with the key.
 int size()
          Answers the number of elements in this Map.
 java.lang.String toString()
           
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

ConcurrentServiceReferenceMap

public ConcurrentServiceReferenceMap(java.lang.String name)
Create a new ConcurrentServiceReferenceMap for the named service. e.g. from bnd.bnd: referenceName=.... or from component.xml:

Parameters:
name - Name of DS reference
Method Detail

activate

public void activate(org.osgi.service.component.ComponentContext context)

deactivate

public void deactivate(org.osgi.service.component.ComponentContext context)
Deactivates the map.


toString

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

putReference

public boolean putReference(K key,
                            org.osgi.framework.ServiceReference<V> reference)
Associates the reference with the key.

Parameters:
key - Key associated with this reference
reference - ServiceReference for the target service
Returns:
true if this is replacing a previous (non-null) service reference

putReferenceIfAbsent

public org.osgi.framework.ServiceReference<V> putReferenceIfAbsent(K key,
                                                                   org.osgi.framework.ServiceReference<V> reference)
Associates the reference with the key but only if there is not an existing reference associated with that key. It will only attempt to add the reference to the map if key is not null.

Parameters:
key - Key associated with this reference
reference - ServiceReference for the target service
Returns:
The service reference that was previously associated with the key or null otherwise
See Also:
ConcurrentMap.putIfAbsent(Object, Object)

removeReference

public boolean removeReference(K key,
                               org.osgi.framework.ServiceReference<V> reference)
Removes the reference associated with the key.

Parameters:
key - Key associated with this reference
reference - ServiceReference associated with service to be unset.
Returns:
true if reference was unset (not previously replaced)

isEmpty

public boolean isEmpty()
Check if there are any registered/added service references: this will return true if the set is empty (none available). If the set is not empty, the services will only be resolvable if there is a viable component context.

Returns:
true if the list of registered service references is empty.

size

public int size()
Answers the number of elements in this Map.

Returns:
the number of elements in this Map

keySet

public java.util.Set<K> keySet()
Answers a Set of the keys contained in this Map in no specific order. The set is backed by this Map so changes to one are reflected by the other. The set does not support adding.

Returns:
a Set of the keys

references

public java.lang.Iterable<org.osgi.framework.ServiceReference<V>> references()

getService

public V getService(K key)
Retrieve the service associated with key.

Parameters:
key - The key associated with the requested service
Returns:
The service if available, null otherwise.

getServiceWithException

public V getServiceWithException(K key)
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

getReference

public org.osgi.framework.ServiceReference<V> getReference(K key)
Returns the ServiceReference associated with key

Parameters:
key - The key associated with the service
Returns:
ServiceRerefence associated with key, or null

getServices

public java.util.Iterator<V> getServices()
Iterate over all services in the map in no specific order. The iterator will return the service associated with each ServiceReference as it progresses. Creation of the iterator does not eagerly resolve services: resolution is done only once per service reference, and only when "next" would retrieve that service.