opendaylight/md-sal/sal-common-impl/src/main/java/org/opendaylight/controller/md/sal/common/impl/ListenerRegistry.java

   1 package org.opendaylight.controller.md.sal.common.impl;
   2
   3 import java.util.Collections;
   4 import java.util.EventListener;
   5 import java.util.HashSet;
   6 import java.util.Set;
   7 import java.util.concurrent.ConcurrentHashMap;
   8
   9 import static com.google.common.base.Preconditions.*;
  10
  11 import org.opendaylight.yangtools.concepts.AbstractObjectRegistration;
  12 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  13
  14 public class ListenerRegistry<T extends EventListener> {
  15
  16     final Set<ListenerRegistration<T>> listeners;
  17     final Set<ListenerRegistration<T>> unmodifiableView;
  18
  19     public ListenerRegistry() {
  20         listeners = new HashSet<>();
  21         unmodifiableView = Collections.unmodifiableSet(listeners);
  22     }
  23
  24     public Iterable<ListenerRegistration<T>> getListeners() {
  25         return unmodifiableView;
  26     }
  27
  28
  29     public ListenerRegistration<T> register(T listener) {
  30         checkNotNull(listener, "Listener should not be null.");
  31         ListenerRegistrationImpl<T> ret = new ListenerRegistrationImpl<T>(listener);
  32         listeners.add(ret);
  33         return ret;
  34     }
  35
  36
  37     @SuppressWarnings("rawtypes")
  38     private void remove(ListenerRegistrationImpl registration) {
  39         listeners.remove(registration);
  40     }
  41
  42     private class ListenerRegistrationImpl<P extends EventListener> //
  43             extends AbstractObjectRegistration<P> //
  44             implements ListenerRegistration<P> {
  45
  46         public ListenerRegistrationImpl(P instance) {
  47             super(instance);
  48         }
  49
  50         @Override
  51         protected void removeRegistration() {
  52             ListenerRegistry.this.remove(this);
  53         }
  54     }
  55 }