Merge pull request #139 from whym/dbopenhelper-singleton

Make DbOpenHelper a singleton class accessible from different content provides

Author: nicolas-raoul

commons/app/src/main/java/fr/free/nrw/commons/CommonsApplication.java

@@ -45,7 +45,6 @@
 )
 public class CommonsApplication extends Application {
 
-    private DBOpenHelper dbOpenHelper;
     public static String APPLICATION_VERSION; // Populated in onCreate. Race conditions theoretically possible, but practically not?
 
     private MWApi api;
@@ -87,15 +86,6 @@ public static MWApi createMWApi() {
         return new MWApi(API_URL, createHttpClient());
     }
 
-
-    public DBOpenHelper getDbOpenHelper() {
-        if(dbOpenHelper == null) {
-            dbOpenHelper = new DBOpenHelper(this);
-        }
-        return dbOpenHelper;
-    }
-
-
     @Override
     public void onCreate() {
         ACRA.init(this);

commons/app/src/main/java/fr/free/nrw/commons/category/CategoryContentProvider.java

@@ -37,7 +37,7 @@ public static Uri uriForId(int id) {
     private DBOpenHelper dbOpenHelper;
     @Override
     public boolean onCreate() {
-        dbOpenHelper = ((CommonsApplication)this.getContext().getApplicationContext()).getDbOpenHelper();
+        dbOpenHelper = DBOpenHelper.getInstance(getContext());
         return false;
     }
 

commons/app/src/main/java/fr/free/nrw/commons/contributions/ContributionsContentProvider.java

@@ -34,7 +34,7 @@ public static Uri uriForId(int id) {
     private DBOpenHelper dbOpenHelper;
     @Override
     public boolean onCreate() {
-        dbOpenHelper = ((CommonsApplication)this.getContext().getApplicationContext()).getDbOpenHelper();
+        dbOpenHelper = DBOpenHelper.getInstance(getContext());
         return false;
     }
 

commons/app/src/main/java/fr/free/nrw/commons/data/DBOpenHelper.java

@@ -11,8 +11,16 @@ public class DBOpenHelper  extends SQLiteOpenHelper{
 
     private static final String DATABASE_NAME = "commons.db";
     private static final int DATABASE_VERSION = 6;
+    private static DBOpenHelper singleton = null;
 
-    public DBOpenHelper(Context context) {
+    public static synchronized DBOpenHelper getInstance(Context context) {
+        if ( singleton == null ) {
+            singleton = new DBOpenHelper(context);
+        }
+        return singleton;
+    }
+
+    private DBOpenHelper(Context context) {
         super(context, DATABASE_NAME, null, DATABASE_VERSION);
     }
 

commons/app/src/main/java/fr/free/nrw/commons/modifications/ModificationsContentProvider.java

@@ -34,7 +34,7 @@ public static Uri uriForId(int id) {
     private DBOpenHelper dbOpenHelper;
     @Override
     public boolean onCreate() {
-        dbOpenHelper = ((CommonsApplication)this.getContext().getApplicationContext()).getDbOpenHelper();
+        dbOpenHelper = DBOpenHelper.getInstance(getContext());
         return false;
     }