Unify listener addition, fix hasDataChanged

Change-Id: Iaf07157fabd5e1a1c698be2832e11716e53812d1

Author: samtstern

common/src/main/java/com/firebase/ui/common/BaseObservableSnapshotArray.java

@@ -21,6 +21,9 @@ public abstract class BaseObservableSnapshotArray<S, L extends BaseChangeEventLi
     private final List<L> mListeners = new CopyOnWriteArrayList<>();
     private BaseSnapshotParser<S, E> mParser;
 
+    /**
+     * True if there has been a "data changed" event since the array was created, false otherwise.
+     */
     private boolean mHasDataChanged = false;
 
     /**
@@ -50,7 +53,16 @@ protected void onCreate() {}
      * state and fire backlogged events
      * @param listener the added listener.
      */
-    protected void onListenerAdded(L listener) {};
+    @CallSuper
+    protected void onListenerAdded(L listener) {
+        for (int i = 0; i < size(); i++) {
+            listener.onChildChanged(ChangeEventType.ADDED, get(i), i, -1);
+        }
+
+        if (mHasDataChanged) {
+            listener.onDataChanged();
+        }
+    };
 
     /**
      * Called when the {@link BaseObservableSnapshotArray} is inactive and should stop listening to the
@@ -140,16 +152,6 @@ public E getObject(int index) {
         return mParser.parseSnapshot(get(index));
     }
 
-    @Override
-    public S get(int index) {
-        return getSnapshots().get(index);
-    }
-
-    @Override
-    public int size() {
-        return getSnapshots().size();
-    }
-
     protected void notifyListenersOnChildChanged(ChangeEventType type,
                                                  S snapshot,
                                                  int newIndex,
@@ -167,18 +169,6 @@ protected void notifyListenersOnDataChanged() {
         }
     }
 
-
-    // TODO(samstern): Do we need this?
-    protected abstract List<S> getSnapshots();
-
-    protected boolean hasDataChanged() {
-        return mHasDataChanged;
-    }
-
-    protected void setHasDataChanged(boolean hasDataChanged) {
-        mHasDataChanged = hasDataChanged;
-    }
-
     protected BaseSnapshotParser<S, E> getSnapshotParser() {
         return mParser;
     }

database/src/main/java/com/firebase/ui/database/FirebaseArray.java

@@ -60,11 +60,6 @@ private void init(Query query) {
         mQuery = query;
     }
 
-    @Override
-    protected List<DataSnapshot> getSnapshots() {
-        return mSnapshots;
-    }
-
     @Override
     protected void onCreate() {
         super.onCreate();
@@ -141,6 +136,21 @@ private int getIndexForKey(String key) {
         throw new IllegalArgumentException("Key not found");
     }
 
+    @Override
+    public DataSnapshot get(int i) {
+        return mSnapshots.get(i);
+    }
+
+    @Override
+    protected List<DataSnapshot> getSnapshots() {
+        return mSnapshots;
+    }
+
+    @Override
+    public int size() {
+        return mSnapshots.size();
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj) return true;

database/src/main/java/com/firebase/ui/database/ObservableSnapshotArray.java

@@ -56,18 +56,8 @@ public ChangeEventListener addChangeEventListener(@NonNull ChangeEventListener l
         return super.addChangeEventListener(listener);
     }
 
-    @Override
-    protected void onListenerAdded(ChangeEventListener listener) {
-        super.onListenerAdded(listener);
-
-        for (int i = 0; i < size(); i++) {
-            listener.onChildChanged(ChangeEventType.ADDED, get(i), i, -1);
-        }
-
-        if (hasDataChanged()) {
-            listener.onDataChanged();
-        }
-    }
+    // TODO(samstern): Can I remove this?
+    protected abstract List<DataSnapshot> getSnapshots();
 
     protected void notifyListenersOnCancelled(DatabaseError error) {
         for (ChangeEventListener listener : getListeners()) {

firestore/src/main/java/com/firebase/ui/firestore/FirestoreArray.java

@@ -65,20 +65,6 @@ protected void onDestroy() {
         mCache.clearData();
     }
 
-    @Override
-    protected void onListenerAdded(ChangeEventListener listener) {
-        super.onListenerAdded(listener);
-
-        for (int i = 0; i < size(); i++) {
-            listener.onChildChanged(ChangeEventType.ADDED, get(i), i, -1);
-        }
-
-        // TODO(samstern): track hasDataChanged()
-        if (hasDataChanged()) {
-            listener.onDataChanged();
-        }
-    }
-
     @Override
     public void onEvent(QuerySnapshot snapshots, FirebaseFirestoreException e) {
         if (e != null) {
@@ -106,6 +92,16 @@ public void onEvent(QuerySnapshot snapshots, FirebaseFirestoreException e) {
         notifyListenersOnDataChanged();
     }
 
+    @Override
+    public DocumentSnapshot get(int i) {
+        return mSnapshots.get(i);
+    }
+
+    @Override
+    public int size() {
+        return mSnapshots.size();
+    }
+
     private void onDocumentAdded(DocumentChange change) {
         Log.d(TAG, "Added: " + change.getNewIndex());
 
@@ -148,11 +144,6 @@ private void onDocumentModified(DocumentChange change) {
         }
     }
 
-    @Override
-    protected List<DocumentSnapshot> getSnapshots() {
-        return mSnapshots;
-    }
-
     private void startListening() {
         if (mRegistration != null) {
             Log.d(TAG, "startListening: already listening.");