From ddcf536e512ae5b4653303711a11d32fbdd81677 Mon Sep 17 00:00:00 2001
From: Miguel Astor <sonofgrendel@gmail.com>
Date: Thu, 28 Nov 2013 09:16:52 -0430
Subject: [PATCH] Networking threads are singletons now.

---
 src/ve/ucv/ciens/ccg/nxtar/NxtARCore.java     |  6 +--
 .../ccg/nxtar/network/RobotControlThread.java | 16 +++++++-
 .../nxtar/network/ServiceDiscoveryThread.java | 37 ++++++++++++++++++-
 .../nxtar/network/VideoStreamingThread.java   | 17 +++++++--
 4 files changed, 66 insertions(+), 10 deletions(-)

diff --git a/src/ve/ucv/ciens/ccg/nxtar/NxtARCore.java b/src/ve/ucv/ciens/ccg/nxtar/NxtARCore.java
index e8ddc36..453e808 100644
--- a/src/ve/ucv/ciens/ccg/nxtar/NxtARCore.java
+++ b/src/ve/ucv/ciens/ccg/nxtar/NxtARCore.java
@@ -69,9 +69,9 @@ public class NxtARCore implements ApplicationListener, NetworkConnectionListener
 
 		Gdx.app.debug(TAG, CLASS_NAME + ".create() :: Creating network threads");
 		mcastEnabler.enableMulticast();
-		udpThread = new ServiceDiscoveryThread();
-		videoThread = new VideoStreamingThread(toaster);
-		robotThread = new RobotControlThread(toaster);
+		udpThread = ServiceDiscoveryThread.getInstance();
+		videoThread = VideoStreamingThread.getInstance().setToaster(toaster);
+		robotThread = RobotControlThread.getInstance().setToaster(toaster);
 
 		udpThread.start();
 		videoThread.start();
diff --git a/src/ve/ucv/ciens/ccg/nxtar/network/RobotControlThread.java b/src/ve/ucv/ciens/ccg/nxtar/network/RobotControlThread.java
index 1dbf3bc..b0bb090 100644
--- a/src/ve/ucv/ciens/ccg/nxtar/network/RobotControlThread.java
+++ b/src/ve/ucv/ciens/ccg/nxtar/network/RobotControlThread.java
@@ -20,10 +20,9 @@ public class RobotControlThread extends Thread {
 	private Socket client;
 	private Toaster toaster;
 
-	public RobotControlThread(Toaster toaster){
+	private RobotControlThread(){
 		super(THREAD_NAME);
 
-		this.toaster = toaster;
 		netListener = null;
 
 		try{
@@ -32,6 +31,19 @@ public class RobotControlThread extends Thread {
 			Gdx.app.error(TAG, CLASS_NAME + ".RobotControlThread() :: Error creating server: " + io.getMessage(), io);
 		}
 	}
+	
+	private static class SingletonHolder{
+		public static final RobotControlThread INSTANCE = new RobotControlThread();
+	}
+
+	public static RobotControlThread getInstance(){
+		return SingletonHolder.INSTANCE;
+	}
+
+	public RobotControlThread setToaster(Toaster toaster){
+		this.toaster = toaster;
+		return this;
+	}
 
 	public void addNetworkConnectionListener(NetworkConnectionListener listener){
 		netListener = listener;
diff --git a/src/ve/ucv/ciens/ccg/nxtar/network/ServiceDiscoveryThread.java b/src/ve/ucv/ciens/ccg/nxtar/network/ServiceDiscoveryThread.java
index 7f78faf..3a3a09b 100644
--- a/src/ve/ucv/ciens/ccg/nxtar/network/ServiceDiscoveryThread.java
+++ b/src/ve/ucv/ciens/ccg/nxtar/network/ServiceDiscoveryThread.java
@@ -21,7 +21,6 @@ import com.badlogic.gdx.Gdx;
  * a row, whichever happens first.</p>
  * 
  * @author miky
- * @since 27/11/2013
  */
 public class ServiceDiscoveryThread extends Thread {
 	/**
@@ -41,12 +40,24 @@ public class ServiceDiscoveryThread extends Thread {
 	 */
 	private static final int MAX_RETRIES = 5;
 
+	/**
+	 * A semaphore object used to synchronize acces to this thread finish flag.
+	 */
 	private Object semaphore;
+	/**
+	 * The finish flag.
+	 */
 	private boolean done;
+	/**
+	 * The UDP server socket used for the ad hoc service discovery protocol.
+	 */
 	private DatagramSocket udpServer;
+	/**
+	 * Holder for the multicast address used in the protocol.
+	 */
 	private InetAddress group;
 
-	public ServiceDiscoveryThread(){
+	private ServiceDiscoveryThread(){
 		// Setup this thread name.
 		super(THREAD_NAME);
 
@@ -71,6 +82,28 @@ public class ServiceDiscoveryThread extends Thread {
 		Gdx.app.debug(TAG, CLASS_NAME + ".ServiceDiscoveryThread() :: Multicast server created.");
 	}
 
+	/**
+	 * Singleton holder for this class.
+	 */
+	private static class SingletonHolder{
+		public static final ServiceDiscoveryThread INSTANCE = new ServiceDiscoveryThread();
+	}
+
+	/**
+	 * Get the singleton instance of this class.
+	 * 
+	 * @return The singleton instance.
+	 */
+	public static ServiceDiscoveryThread getInstance(){
+		return SingletonHolder.INSTANCE;
+	}
+
+	/**
+	 * This thread's run method.
+	 * 
+	 * <p>This method executes the ad hoc service discovery protocol implemented by this class, as
+	 * described in the class introduction.</p>
+	 */
 	@Override
 	public void run(){
 		int retries = 0;
diff --git a/src/ve/ucv/ciens/ccg/nxtar/network/VideoStreamingThread.java b/src/ve/ucv/ciens/ccg/nxtar/network/VideoStreamingThread.java
index 9bb70f1..fc5fd8f 100644
--- a/src/ve/ucv/ciens/ccg/nxtar/network/VideoStreamingThread.java
+++ b/src/ve/ucv/ciens/ccg/nxtar/network/VideoStreamingThread.java
@@ -20,12 +20,10 @@ public class VideoStreamingThread extends Thread {
 	private Socket client;
 	private Toaster toaster;
 
-	public VideoStreamingThread(Toaster toaster){
+	private VideoStreamingThread(){
 		super(THREAD_NAME);
 
-		this.toaster = toaster;
 		netListener = null;
-
 		try{
 			server = new ServerSocket(ProjectConstants.SERVER_TCP_PORT_1);
 		}catch(IOException io){
@@ -33,6 +31,19 @@ public class VideoStreamingThread extends Thread {
 		}
 	}
 
+	private static class SingletonHolder{
+		public static final VideoStreamingThread INSTANCE = new VideoStreamingThread();
+	}
+
+	public static VideoStreamingThread getInstance(){
+		return SingletonHolder.INSTANCE;
+	}
+
+	public VideoStreamingThread setToaster(Toaster toaster){
+		this.toaster = toaster;
+		return this;
+	}
+
 	public void addNetworkConnectionListener(NetworkConnectionListener listener){
 		netListener = listener;
 	}