Started programming the robot control threads.

src/ve/ucv/ciens/ccg/nxtcam/robotcontrol/MotorEventQueue.java

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+package ve.ucv.ciens.ccg.nxtcam.robotcontrol;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+import ve.ucv.ciens.ccg.networkdata.MotorEvent;
+
+/**
+ * <p>A simple monitor class that encapsulates a queue.</p>
+ * <p>As it name says it stores motor events to be forwarded to the NXT robot.</p>
+ * <p>This class implements the singleton design pattern.<p> 
+ * 
+ * @author Miguel Angel Astor Romero
+ */
+public class MotorEventQueue {
+	/**
+	 * The event queue implemented as a linked list.
+	 */
+	private Queue<MotorEvent> motorEvents;
+
+	private MotorEventQueue(){
+		motorEvents = new LinkedList<MotorEvent>();
+	}
+
+	private static class SingletonHolder{
+		public static final MotorEventQueue instance = new MotorEventQueue();
+	}
+
+	/**
+	 * Return the singleton instance of this class.
+	 * @return The singleton instance.
+	 */
+	public static MotorEventQueue getInstance(){
+		return SingletonHolder.instance;
+	}
+
+	/**
+	 * <p>Get the first event on the queue.</p>
+	 * <p> If there are no events to return this method blocks until some thread calls the addEvent() method.</p>
+	 * @return The event at the front of the queue.
+	 */
+	public synchronized MotorEvent getNextEvent(){
+		while(motorEvents.size() == 0){
+			try{ wait(); }catch(InterruptedException ie){ }
+		}
+		return motorEvents.poll();
+	}
+
+	/**
+	 * <p>Adds an event to the back of the queue.</p>
+	 * @param event The event to add.
+	 */
+	public synchronized void addEvent(MotorEvent event){
+		motorEvents.add(event);
+		notifyAll();
+	}
+}