Fix duplicated countdown filter bossbars (#1407)

Signed-off-by: Pablo Herrera <[email protected]>

core/src/main/java/tc/oc/pgm/api/filter/ReactorFactory.java

@@ -16,7 +16,8 @@ public interface ReactorFactory<R extends ReactorFactory.Reactor>
     extends FilterDefinition, StateHolder<R> {
 
   default void register(Match match, FilterMatchModule fmm) {
-    match.getFeatureContext().registerState(this, createReactor(match, fmm));
+    if (!match.getFeatureContext().hasState(this))
+      match.getFeatureContext().registerState(this, createReactor(match, fmm));
   }
 
   /**

core/src/main/java/tc/oc/pgm/features/MatchFeatureContext.java

@@ -8,28 +8,35 @@
 import tc.oc.pgm.api.feature.Feature;
 import tc.oc.pgm.util.collection.ContextStore;
 
-public class MatchFeatureContext extends ContextStore<Feature> {
+public class MatchFeatureContext extends ContextStore<Feature<?>> {
 
   private final Map<StateHolder<?>, Object> states = new IdentityHashMap<>();
 
-  public String add(Feature feature) {
+  public String add(Feature<?> feature) {
     super.add(feature.getId(), feature);
     return feature.getId();
   }
 
-  public <T extends Feature> T get(String id, Class<T> type) {
+  @SuppressWarnings("unchecked")
+  public <T extends Feature<?>> T get(String id, Class<T> type) {
     return (T) this.get(id);
   }
 
   public <T> void registerState(StateHolder<T> stateHolder, T state) {
-    states.put(stateHolder, state);
+    if (states.putIfAbsent(stateHolder, state) != null) {
+      throw new IllegalStateException("State already registered: " + stateHolder);
+    }
   }
 
+  @SuppressWarnings("unchecked")
   public <T> T getState(StateHolder<T> stateHolder) {
-    //noinspection unchecked
     return (T) assertNotNull(states.get(stateHolder), "state");
   }
 
+  public boolean hasState(StateHolder<?> stateHolder) {
+    return states.containsKey(stateHolder);
+  }
+
   public Map<StateHolder<?>, Object> getStates() {
     return Collections.unmodifiableMap(states);
   }