Bug 1372681 - [2.3] Add GeckoViewHandler utility class for event handler registration. r=snorp,jchen

mobile/android/base/moz.build

@@ -384,6 +384,7 @@ gvjar.sources += [geckoview_source_dir + 'java/org/mozilla/gecko/' + x
     'GeckoThread.java',
     'GeckoView.java',
     'GeckoViewFragment.java',
+    'GeckoViewHandler.java',
     'GeckoViewSettings.java',
     'gfx/BitmapUtils.java',
     'gfx/BufferedImage.java',

mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoViewHandler.java

@@ -0,0 +1,74 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * vim: ts=4 sw=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko;
+
+import org.mozilla.gecko.util.BundleEventListener;
+import org.mozilla.gecko.util.EventCallback;
+import org.mozilla.gecko.util.GeckoBundle;
+
+import android.util.Log;
+
+
+/* package */ abstract class GeckoViewHandler<Listener>
+    implements BundleEventListener {
+
+    private static final String LOGTAG = "GeckoViewHandler";
+    private static final boolean DEBUG = false;
+
+    private Listener mListener;
+    private final String mModuleName;
+    private final String[] mEvents;
+
+    GeckoViewHandler(final String module, final GeckoView view,
+                     final String[] events) {
+        mModuleName = module;
+        mEvents = events;
+    }
+
+    public Listener getListener() {
+        return mListener;
+    }
+
+    public void setListener(final Listener listener, final GeckoView view) {
+        final EventDispatcher eventDispatcher = view.getEventDispatcher();
+
+        if (mListener != null && mListener != listener) {
+            final GeckoBundle msg = new GeckoBundle(1);
+            msg.putString("module", mModuleName);
+            eventDispatcher.dispatch("GeckoView:Unregister", msg);
+            eventDispatcher.unregisterUiThreadListener(this, mEvents);
+        }
+
+        mListener = listener;
+
+        if (mListener == null) {
+            return;
+        }
+
+        final GeckoBundle msg = new GeckoBundle(1);
+        msg.putString("module", mModuleName);
+        eventDispatcher.dispatch("GeckoView:Register", msg);
+        eventDispatcher.registerUiThreadListener(this, mEvents);
+    }
+
+    @Override
+    public void handleMessage(final String event, final GeckoBundle message,
+                              final EventCallback callback) {
+        if (DEBUG) {
+            Log.d(LOGTAG, mModuleName + " handleMessage: event = " + event);
+        }
+
+        if (mListener != null) {
+            handleMessage(mListener, event, message, callback);
+        }
+    }
+
+    protected abstract void handleMessage(final Listener listener,
+                                          final String event,
+                                          final GeckoBundle message,
+                                          final EventCallback callback);
+}