Fixed Fatal Exception: android.database.sqlite.SQLiteDatabaseLockedException

Author: Phu Tran

aws-android-sdk-appsync/src/main/java/com/amazonaws/mobileconnectors/appsync/AWSAppSyncClient.java

@@ -891,7 +891,7 @@ private void clearDeltaSyncStore() {
         Log.d(TAG, "Clearing the delta sync store.");
 
         AWSAppSyncDeltaSyncSqlHelper awsAppSyncDeltaSyncSqlHelper =
-                new AWSAppSyncDeltaSyncSqlHelper(
+                AWSAppSyncDeltaSyncSqlHelper.create(
                     applicationContext,
                     deltaSyncSqlStoreName);
         new AWSAppSyncDeltaSyncDBOperations(awsAppSyncDeltaSyncSqlHelper)

aws-android-sdk-appsync/src/main/java/com/amazonaws/mobileconnectors/appsync/AWSAppSyncDeltaSync.java

@@ -115,7 +115,7 @@ private void initializeIfRequired() {
             if (awsAppSyncDeltaSyncSqlHelper == null) {
                 //Setup up the local store
                 Log.d(TAG, "Initializing the database");
-                awsAppSyncDeltaSyncSqlHelper = new AWSAppSyncDeltaSyncSqlHelper(mContext,
+                awsAppSyncDeltaSyncSqlHelper = AWSAppSyncDeltaSyncSqlHelper.create(mContext,
                         awsAppSyncClient.deltaSyncSqlStoreName);
             }
 

aws-android-sdk-appsync/src/main/java/com/amazonaws/mobileconnectors/appsync/AWSAppSyncDeltaSyncSqlHelper.java

@@ -12,6 +12,8 @@
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 
+import java.util.Hashtable;
+
 /*
     Delta Sync Database Helper
  */
@@ -25,6 +27,8 @@ class AWSAppSyncDeltaSyncSqlHelper extends SQLiteOpenHelper {
     private static final String DATABASE_NAME = "appsync_deltasync_db";
     private static final int DATABASE_VERSION = 1;
 
+    private static Hashtable<String, AWSAppSyncDeltaSyncSqlHelper> sInstances = new Hashtable<>();
+
     //Database Create Statement
     private static final String DATABASE_CREATE = String.format(
             "create table %s( %s integer primary key autoincrement, %s text not null, %s Integer);",
@@ -35,15 +39,23 @@ class AWSAppSyncDeltaSyncSqlHelper extends SQLiteOpenHelper {
 
 
     //Constructor
-    public AWSAppSyncDeltaSyncSqlHelper(Context context) {
+    private AWSAppSyncDeltaSyncSqlHelper(Context context) {
         super(context, DATABASE_NAME, null, DATABASE_VERSION);
     }
 
     //Constructor
-    public AWSAppSyncDeltaSyncSqlHelper(Context context, String databaseName) {
+    private AWSAppSyncDeltaSyncSqlHelper(Context context, String databaseName) {
         super(context, databaseName, null, DATABASE_VERSION);
     }
 
+    synchronized public static AWSAppSyncDeltaSyncSqlHelper create(Context context, String databaseName) {
+        AWSAppSyncDeltaSyncSqlHelper instance = sInstances.get(databaseName);
+        if (instance == null) {
+            instance = new AWSAppSyncDeltaSyncSqlHelper(context);
+            sInstances.put(databaseName, instance);
+        }
+        return instance;
+    }
 
     @Override
     /*