Replace LooperExecutor with built-in class in Android AppRTC Demo

webrtc/examples/androidapp/src/org/appspot/apprtc/DirectRTCClient.java

 /*
  *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 package org.appspot.apprtc;
 
 import android.util.Log;
 
-import org.appspot.apprtc.util.LooperExecutor;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.webrtc.IceCandidate;
 import org.webrtc.PeerConnection;
 import org.webrtc.SessionDescription;
 
 import java.util.LinkedList;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 /**
  * Implementation of AppRTCClient that uses direct TCP connection as the signaling channel.
  * This eliminates the need for an external server. This class does not support loopback
  * connections.
  */
 public class DirectRTCClient implements AppRTCClient, TCPChannelClient.TCPChannelEvents {
   private static final String TAG = "DirectRTCClient";
@@ skipping 11 matching lines @@
         // IPv6 without []
         + "((([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})?::(([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})?)|"
         + "(([0-9a-fA-F]{1,4}:)*[0-9a-fA-F]{1,4})|"
         // Literals
         + "localhost"
       + ")"
       // Optional port number
       + "(:(\\d+))?"
   );
 
-  private final LooperExecutor executor;
+  private final ExecutorService executor;
   private final SignalingEvents events;
   private TCPChannelClient tcpClient;
   private RoomConnectionParameters connectionParameters;
 
   private enum ConnectionState {
     NEW, CONNECTED, CLOSED, ERROR
   };
 
   // All alterations of the room state should be done from inside the looper thread.
   private ConnectionState roomState;
 
-  public DirectRTCClient(SignalingEvents events, LooperExecutor looperExecutor) {
+  public DirectRTCClient(SignalingEvents events) {
     this.events = events;
-    executor = looperExecutor;
 
-    executor.requestStart();
+    executor = Executors.newSingleThreadExecutor();
     roomState = ConnectionState.NEW;
   }
 
   /**
    * Connects to the room, roomId in connectionsParameters is required. roomId must be a valid
    * IP address matching IP_PATTERN.
    */
   @Override
   public void connectToRoom(RoomConnectionParameters connectionParameters) {
     this.connectionParameters = connectionParameters;
@@ skipping 59 matching lines @@
    *
    * Runs on the looper thread.
    */
   private void disconnectFromRoomInternal() {
     roomState = ConnectionState.CLOSED;
 
     if (tcpClient != null) {
       tcpClient.disconnect();
       tcpClient = null;
     }
+    executor.shutdown();

[magjed_webrtc, 2016/05/19 12:07:54]

What happens if connectToRoom() is called again? Better to shut down in
onTCPClose/onTCPError?

[sakal, 2016/05/19 12:39:03]

Executor gets shutdown too early if it is shutdown on onTCPClose. AppRTCClient
objects are currently treated as single use objects. If we want to make the code
future proof, we can remove final from Executor and reinitialize it on
connectToRoom.

   }
 
   @Override
   public void sendOfferSdp(final SessionDescription sdp) {
     executor.execute(new Runnable() {
       @Override
       public void run() {
         if (roomState != ConnectionState.CONNECTED) {
           reportError("Sending offer SDP in non connected state.");
           return;
@@ skipping 127 matching lines @@
         reportError("Unexpected TCP message: " + msg);
       }
     } catch (JSONException e) {
       reportError("TCP message JSON parsing error: " + e.toString());
     }
   }
 
   @Override
   public void onTCPError(String description) {
     reportError("TCP connection error: " + description);
-    executor.requestStop();
   }
 
   @Override
   public void onTCPClose() {
     events.onChannelClose();
-    executor.requestStop();
   }
 
   // --------------------------------------------------------------------
   // Helper functions.
   private void reportError(final String errorMessage) {
     Log.e(TAG, errorMessage);
     executor.execute(new Runnable() {
       @Override
       public void run() {
         if (roomState != ConnectionState.ERROR) {
@@ skipping 31 matching lines @@
     return json;
   }
 
   // Converts a JSON candidate to a Java object.
   private static IceCandidate toJavaCandidate(JSONObject json) throws JSONException {
     return new IceCandidate(json.getString("id"),
         json.getInt("label"),
         json.getString("candidate"));
   }
 }