+ mObservers = new ArrayList<>();
+ }
+
+ /**
+ * Register for callbacks from this cluster matcher.
+ * @param observer The target of the callbacks.
+ */
+ public final void addObserver(ClusterMatcherObserver observer) {
+ mObservers.add(observer);
+ }
+
+ /**
+ * Deregister for callbacks from this cluster matcher.
+ * @param observer The callback target that is to be deregistered.
+ */
+ public final void removeObserver(ClusterMatcherObserver observer) {
+ mObservers.remove(observer);