Issue 6307 - Introduce external engine created callback

libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java

Index: libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java
diff --git a/libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java b/libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java
index 66b346e49e6fe66ed73aa1a03f9b2e84517f228e..51900ee8c68d7325b3d9cf4a5695e47b17e02b89 100644
--- a/libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java
+++ b/libadblockplus-android/src/org/adblockplus/libadblockplus/android/SingleInstanceEngineProvider.java
@@ -23,6 +23,8 @@ import android.content.SharedPreferences;
 import android.net.ConnectivityManager;
 import android.util.Log;
 
+import java.util.LinkedList;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -42,8 +44,8 @@ public class SingleInstanceEngineProvider implements AdblockEngineProvider
   private AdblockEngine engine;
   private CountDownLatch engineCreated;
   private Long v8IsolateProviderPtr;
-  private Runnable engineCreatedCallback;
-  private Runnable engineDisposedCallback;
+  private List<Runnable> engineCreatedCallbacks = new LinkedList<Runnable>();
+  private List<Runnable> engineDisposedCallbacks = new LinkedList<Runnable>();
 
   /*
     Simple ARC management for AdblockEngine
@@ -89,18 +91,28 @@ public class SingleInstanceEngineProvider implements AdblockEngineProvider
     return this;
   }
 
-  public SingleInstanceEngineProvider setEngineCreatedCallback(Runnable callback)
+  public SingleInstanceEngineProvider addEngineCreatedCallback(Runnable callback)
   {
-    this.engineCreatedCallback = callback;
+    this.engineCreatedCallbacks.add(callback);
     return this;
   }
 
-  public SingleInstanceEngineProvider setEngineDisposedCallback(Runnable callback)
+  public void removeEngineCreatedCallback(Runnable callback)

[anton, 2018/01/24 12:51:08]

"remove.." methods are not used anywhere but could be used.
also we could add "clear.." methods too for consistency.
What do you think?

[sergei, 2018/01/24 13:33:02]

I would say if someone wants to remove or clear then just create a new instance
of SingleInstanceEngineProvider and abandon the present one.

[jens, 2018/01/26 08:15:22]

Even if Sergejs idea is also fine I would prefer to be consistent and add a
clear method too.

[anton, 2018/01/26 08:22:58]

Acknowledged.

   {
-    this.engineDisposedCallback = callback;
+    this.engineCreatedCallbacks.remove(callback);
+  }
+
+  public SingleInstanceEngineProvider addEngineDisposedCallback(Runnable callback)
+  {
+    this.engineDisposedCallbacks.add(callback);
     return this;
   }
 
+  public void removeEngineDisposedCallback(Runnable callback)
+  {
+    this.engineDisposedCallbacks.remove(callback);
+  }
+
   private void createAdblock()
   {
     ConnectivityManager connectivityManager =
@@ -139,9 +151,9 @@ public class SingleInstanceEngineProvider implements AdblockEngineProvider
     Log.d(TAG, "AdblockHelper engine created");
 
     // sometimes we need to init AdblockEngine instance, eg. set user settings
-    if (engineCreatedCallback != null)
+    for (Runnable callback : engineCreatedCallbacks)
     {
-      engineCreatedCallback.run();
+      callback.run();
     }
   }
 
@@ -241,9 +253,9 @@ public class SingleInstanceEngineProvider implements AdblockEngineProvider
 
     // sometimes we need to deinit something after AdblockEngine instance disposed
     // eg. release user settings
-    if (engineDisposedCallback != null)
+    for (Runnable callback : engineDisposedCallbacks)
     {
-      engineDisposedCallback.run();
+      callback.run();
     }
   }