hardening provider implementation + javadoc

src/com/owncloud/android/datamodel/SyncedFolderProvider.java

@@ -1,22 +1,21 @@
 /**
- * Nextcloud Android client application
+ *   Nextcloud Android client application
  *
- * @author Andy Scherzinger
- * Copyright (C) 2016 Andy Scherzinger
- * Copyright (C) 2016 Nextcloud
- * <p>
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
- * License as published by the Free Software Foundation; either
- * version 3 of the License, or any later version.
- * <p>
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU AFFERO GENERAL PUBLIC LICENSE for more details.
- * <p>
- * You should have received a copy of the GNU Affero General Public
- * License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *   Copyright (C) 2016 Andy Scherzinger
+ *   Copyright (C) 2016 Nextcloud.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
+ *   License as published by the Free Software Foundation; either
+ *   version 3 of the License, or any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU AFFERO GENERAL PUBLIC LICENSE for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public
+ *   License along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 package com.owncloud.android.datamodel;
 
@@ -29,14 +28,21 @@ import android.support.annotation.NonNull;
 import com.owncloud.android.db.ProviderMeta;
 import com.owncloud.android.lib.common.utils.Log_OC;
 
+import java.util.Observable;
+
 /**
  * Database provider for handling the persistence aspects of synced folders.
  */
-public class SyncedFolderProvider {
+public class SyncedFolderProvider extends Observable {
     static private final String TAG = SyncedFolderProvider.class.getSimpleName();
 
     private ContentResolver mContentResolver;
 
+    /**
+     * constructor.
+     *
+     * @param contentResolver the ContentResolver to work with.
+     */
     public SyncedFolderProvider(ContentResolver contentResolver) {
         if (contentResolver == null) {
             throw new IllegalArgumentException("Cannot create an instance with a NULL contentResolver");
@@ -58,6 +64,7 @@ public class SyncedFolderProvider {
         Uri result = mContentResolver.insert(ProviderMeta.ProviderTableMeta.CONTENT_URI_SYNCED_FOLDERS, cv);
 
         if (result != null) {
+            notifyFolderSyncObservers();
             return Long.parseLong(result.getPathSegments().get(1));
         } else {
             Log_OC.e(TAG, "Failed to insert item " + syncedFolder.getLocalPath() + " into folder sync db.");
@@ -65,29 +72,40 @@ public class SyncedFolderProvider {
         }
     }
 
+    /**
+     * get all synced folder entries.
+     *
+     * @return all synced folder entries, empty if none have been found
+     */
     public SyncedFolder[] getSyncedFolders() {
-        Cursor c = mContentResolver.query(
+        Cursor cursor = mContentResolver.query(
                 ProviderMeta.ProviderTableMeta.CONTENT_URI_SYNCED_FOLDERS,
                 null,
                 "1=1",
                 null,
                 null
         );
-        SyncedFolder[] list = new SyncedFolder[c.getCount()];
-        if (c.moveToFirst()) {
-            do {
-                SyncedFolder syncedFolder = createSyncedFolderFromCursor(c);
-                if (syncedFolder == null) {
-                    Log_OC.e(TAG, "SyncedFolder could not be created from cursor");
-                } else {
-                    list[c.getPosition()] = syncedFolder;
-                }
-            } while (c.moveToNext());
 
+        if (cursor != null) {
+            SyncedFolder[] list = new SyncedFolder[cursor.getCount()];
+            if (cursor.moveToFirst()) {
+                do {
+                    SyncedFolder syncedFolder = createSyncedFolderFromCursor(cursor);
+                    if (syncedFolder == null) {
+                        Log_OC.e(TAG, "SyncedFolder could not be created from cursor");
+                    } else {
+                        list[cursor.getPosition()] = syncedFolder;
+                    }
+                } while (cursor.moveToNext());
+
+            }
+            cursor.close();
+            return list;
+        } else {
+            Log_OC.e(TAG, "DB error creating read all cursor for synced folders.");
         }
-        c.close();
 
-        return list;
+        return new SyncedFolder[0];
     }
 
     /**
@@ -109,10 +127,7 @@ public class SyncedFolderProvider {
                 null
         );
 
-        if (cursor == null || cursor.getCount() != 1) {
-            Log_OC.e(TAG, cursor.getCount() + " items for id=" + id + " available in UploadDb. Expected 1. Failed to " +
-                    "update upload db.");
-        } else {
+        if (cursor != null && cursor.getCount() == 1) {
             while (cursor.moveToNext()) {
                 // read sync folder object and update
                 SyncedFolder syncedFolder = createSyncedFolderFromCursor(cursor);
@@ -121,13 +136,29 @@ public class SyncedFolderProvider {
 
                 // update sync folder object in db
                 result = updateSyncFolder(syncedFolder);
+
+                cursor.close();
+            }
+        } else {
+            if (cursor == null) {
+                Log_OC.e(TAG, "Sync folder db cursor for ID=" + id + " in NULL.");
+            } else {
+                Log_OC.e(TAG, cursor.getCount() + " items for id=" + id + " available in sync folder database. " +
+                        "Expected 1. Failed to update sync folder db.");
             }
         }
-        cursor.close();
+
         return result;
     }
 
+    /**
+     * find a synced folder by local path.
+     *
+     * @param localPath the local path of the local folder
+     * @return the synced folder if found, else null
+     */
     public SyncedFolder findByLocalPath(String localPath) {
+        SyncedFolder result = null;
         Cursor cursor = mContentResolver.query(
                 ProviderMeta.ProviderTableMeta.CONTENT_URI_SYNCED_FOLDERS,
                 null,
@@ -136,28 +167,53 @@ public class SyncedFolderProvider {
                 null
         );
 
-        if (cursor == null || cursor.getCount() != 1) {
-            Log_OC.e(TAG, cursor.getCount() + " items for local path=" + localPath + " available in sync folder db. " +
-                    "Expected 1. Failed to update sync folder db.");
-            return null;
+        if (cursor != null && cursor.getCount() == 1) {
+            result = createSyncedFolderFromCursor(cursor);
+            cursor.close();
         } else {
-            return createSyncedFolderFromCursor(cursor);
+            if (cursor == null) {
+                Log_OC.e(TAG, "Sync folder db cursor for local path=" + localPath + " in NULL.");
+            } else {
+                Log_OC.e(TAG, cursor.getCount() + " items for local path=" + localPath
+                        + " available in sync folder db. Expected 1. Failed to update sync folder db.");
+            }
         }
+
+        return result;
+
     }
 
+    /**
+     * update given synced folder.
+     *
+     * @param syncedFolder the synced folder to be updated.
+     * @return the number of rows updated.
+     */
     private int updateSyncFolder(SyncedFolder syncedFolder) {
         Log_OC.v(TAG, "Updating " + syncedFolder.getLocalPath() + " with enabled=" + syncedFolder.isEnabled());
 
         ContentValues cv = createContentValuesFromSyncedFolder(syncedFolder);
 
-        return mContentResolver.update(
+        int result = mContentResolver.update(
                 ProviderMeta.ProviderTableMeta.CONTENT_URI_UPLOADS,
                 cv,
                 ProviderMeta.ProviderTableMeta._ID + "=?",
                 new String[]{String.valueOf(syncedFolder.getId())}
         );
+
+        if (result > 0) {
+            notifyFolderSyncObservers();
+        }
+
+        return result;
     }
 
+    /**
+     * maps a cursor into a SyncedFolder object.
+     *
+     * @param cursor the cursor
+     * @return the mapped SyncedFolder, null if cursor is null
+     */
     private SyncedFolder createSyncedFolderFromCursor(Cursor cursor) {
         SyncedFolder syncedFolder = null;
         if (cursor != null) {
@@ -177,6 +233,12 @@ public class SyncedFolderProvider {
         return syncedFolder;
     }
 
+    /**
+     * create ContentValues object based on given SyncedFolder.
+     *
+     * @param syncedFolder the synced folder
+     * @return the corresponding ContentValues object
+     */
     @NonNull
     private ContentValues createContentValuesFromSyncedFolder(SyncedFolder syncedFolder) {
         ContentValues cv = new ContentValues();
@@ -190,4 +252,13 @@ public class SyncedFolderProvider {
         cv.put(ProviderMeta.ProviderTableMeta.SYNCED_FOLDER_UPLOAD_ACTION, syncedFolder.getUploadAction());
         return cv;
     }
+
+    /**
+     * Inform all observers about data change.
+     */
+    private void notifyFolderSyncObservers() {
+        Log_OC.d(TAG, "notifying folder sync data observers");
+        setChanged();
+        notifyObservers();
+    }
 }