Issue 6364 - Exclude double initialization of AdblockHelper

libadblockplus-android-settings/src/org/adblockplus/libadblockplus/android/settings/AdblockHelper.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 27 matching lines @@
    * Suggested preference name to store settings
    */
   public static final String PREFERENCE_NAME = "ADBLOCK";
 
   /**
    * Suggested preference name to store intercepted subscription requests
    */
   public static final String PRELOAD_PREFERENCE_NAME = "ADBLOCK_PRELOAD";
   private static AdblockHelper _instance;
 
+  private boolean isInitialized;
   private SingleInstanceEngineProvider provider;
   private AdblockSettingsStorage storage;
 
   private final SingleInstanceEngineProvider.EngineCreatedListener engineCreatedListener =
     new SingleInstanceEngineProvider.EngineCreatedListener()
   {
     @Override
     public void onAdblockEngineCreated(AdblockEngine engine)
     {
       AdblockSettings settings = storage.load();
@@ skipping 76 matching lines @@
    *                 Adblock Plus library will download subscription files and store them on
    *                 the path passed. The path should exist and the directory content should not be
    *                 cleared out occasionally. Using `context.getCacheDir().getAbsolutePath()` is not
    *                 recommended because it can be cleared by the system.
    * @param developmentBuild debug or release?
    * @param preferenceName Shared Preferences name to store adblock settings
    */
   public SingleInstanceEngineProvider init(Context context, String basePath,
                                            boolean developmentBuild, String preferenceName)
   {
+    if (isInitialized)
+    {
+      new IllegalStateException("Usage exception: already initialized. Check `isInit()`");
+    }
+
     initProvider(context, basePath, developmentBuild);
     initStorage(context, preferenceName);
+    isInitialized = true;
     return provider;
   }
 
+  /**
+   * Check if it is already initialized
+   * @return
+   */
+  public boolean isInit() {

[jens, 2018/02/07 09:36:25]

for consistency I would probably call this method isInitialized()

[anton, 2018/02/07 09:52:55]

initialize method is called `init()` to i've names it `isInit()`.
It's undesired to rename `init()` method as it break back compatibility.

[jens, 2018/02/07 10:03:23]

Okay, I don't insist to change it. 
But it's kind of inconsistent to me that the boolean is called isInitialized and
the method is called isInit().

+    return isInitialized;
+  }
+
   private void initProvider(Context context, String basePath, boolean developmentBuild)
   {
     provider = new SingleInstanceEngineProvider(context, basePath, developmentBuild);
     provider.addEngineCreatedListener(engineCreatedListener);
     provider.addEngineDisposedListener(engineDisposedListener);
   }
 
   private void initStorage(Context context, String settingsPreferenceName)
   {
     // read and apply current settings
@@ skipping 42 matching lines @@
 
   /**
    * @deprecated The method is deprecated: use .getProvider().getCounter() instead
    */
   @Deprecated
   public int getCounter()
   {
     return provider.getCounter();
   }
 }