Renaming FirebaseSingleton -> persistence/FirebasePersistence

This is in preparation for factoring out persistence to enable Syncbase
persistence. Also adds a SyncbasePersistence stub class.

Change-Id: I96ef7913eb60dff277e48f0aee7c1cadda02a036
diff --git a/projects/todos/app/src/main/java/io/v/todos/MainActivity.java b/projects/todos/app/src/main/java/io/v/todos/MainActivity.java
index da7119f..a92793e 100644
--- a/projects/todos/app/src/main/java/io/v/todos/MainActivity.java
+++ b/projects/todos/app/src/main/java/io/v/todos/MainActivity.java
@@ -13,7 +13,6 @@
 import android.graphics.Paint;
 import android.os.Bundle;
 import android.support.v7.app.AlertDialog;
-import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.helper.ItemTouchHelper;
 import android.util.Log;
@@ -29,6 +28,8 @@
 import com.firebase.client.Firebase;
 import com.firebase.client.FirebaseError;
 
+import io.v.todos.persistence.FirebasePersistence;
+
 /**
  * MainActivity for Vanadium TODOs
  *
@@ -165,7 +166,7 @@
         }).attachToRecyclerView(recyclerView);
 
         // Prepare our Firebase Reference and the primary listener (SNACKOOS).
-        FirebaseSingleton.getDatabase(this);
+        FirebasePersistence.getDatabase(this);
         myFirebaseRef = new Firebase(FIREBASE_EXAMPLE_URL);
         setUpSnackoos();
     }
diff --git a/projects/todos/app/src/main/java/io/v/todos/TodoListActivity.java b/projects/todos/app/src/main/java/io/v/todos/TodoListActivity.java
index c9a0a3c..2fc7086 100644
--- a/projects/todos/app/src/main/java/io/v/todos/TodoListActivity.java
+++ b/projects/todos/app/src/main/java/io/v/todos/TodoListActivity.java
@@ -13,7 +13,6 @@
 import android.graphics.Paint;
 import android.os.Bundle;
 import android.support.v7.app.AlertDialog;
-import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.helper.ItemTouchHelper;
 import android.util.Log;
@@ -30,6 +29,8 @@
 import com.firebase.client.FirebaseError;
 import com.firebase.client.ValueEventListener;
 
+import io.v.todos.persistence.FirebasePersistence;
+
 /**
  * TodoListActivity for Vanadium TODOs
  *
@@ -164,7 +165,7 @@
         }).attachToRecyclerView(recyclerView);
 
         // Prepare our Firebase Reference and the primary listener (SNACKOOS).
-        FirebaseSingleton.getDatabase(this);
+        FirebasePersistence.getDatabase(this);
         myFirebaseRef = new Firebase(MainActivity.FIREBASE_EXAMPLE_URL);
         setUpSnackoo();
         setUpSnackoos();
diff --git a/projects/todos/app/src/main/java/io/v/todos/FirebaseSingleton.java b/projects/todos/app/src/main/java/io/v/todos/persistence/FirebasePersistence.java
similarity index 73%
rename from projects/todos/app/src/main/java/io/v/todos/FirebaseSingleton.java
rename to projects/todos/app/src/main/java/io/v/todos/persistence/FirebasePersistence.java
index 0efd48c..0e11636 100644
--- a/projects/todos/app/src/main/java/io/v/todos/FirebaseSingleton.java
+++ b/projects/todos/app/src/main/java/io/v/todos/persistence/FirebasePersistence.java
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package io.v.todos;
+package io.v.todos.persistence;
 
 import android.content.Context;
 
@@ -14,10 +14,10 @@
  *
  * @author alexfandrianto
  */
-public class FirebaseSingleton {
-    private FirebaseSingleton() {} // Marked private to prevent accidental instantiation.
+public class FirebasePersistence {
+    private FirebasePersistence() {} // Marked private to prevent accidental instantiation.
 
-    private static FirebaseSingleton singleton;
+    private static FirebasePersistence singleton;
 
     /**
      * Obtain a database singleton that can be used to manipulate data.
@@ -25,9 +25,9 @@
      * @param context An Android context, usually from an Android activity or application.
      * @return
      */
-    public synchronized static FirebaseSingleton getDatabase(Context context) {
+    public synchronized static FirebasePersistence getDatabase(Context context) {
         if (singleton == null) {
-            singleton = new FirebaseSingleton();
+            singleton = new FirebasePersistence();
 
             // Set up Firebase with the context and have it persist data locally even when offline.
             Firebase.setAndroidContext(context);
diff --git a/projects/todos/app/src/main/java/io/v/todos/persistence/SyncbasePersistence.java b/projects/todos/app/src/main/java/io/v/todos/persistence/SyncbasePersistence.java
new file mode 100644
index 0000000..a6ea458
--- /dev/null
+++ b/projects/todos/app/src/main/java/io/v/todos/persistence/SyncbasePersistence.java
@@ -0,0 +1,8 @@
+// Copyright 2016 The Vanadium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package io.v.todos.persistence;
+
+public class SyncbasePersistence {
+}