Refactoring part 6: Commlink

*Removed access to CommLink.java from API.java, now access is directly provided from inside the CommLink class.
*Also removed the array of all the CommLink objects because they were all revering to the same static object so there shouldn't be any difference

src/main/java/com/api/API.java

@@ -2,7 +2,6 @@
 
 import com.api.communications.CommLink;
 import com.setup.Param;
-import com.uavController.UAVParam;
 
 import java.util.concurrent.atomic.AtomicReferenceArray;
 
@@ -38,26 +37,7 @@ public static ArduSim getArduSim() {
 		return API.ardusim;
 
 	}
-
-	/**
-	 * Get the communication link needed for UAV-to-UAV communications.
-	 * @param numUAV This specific UAV position in the data arrays (see documentation).
-	 * @return Communication link used by the UAV to communicate with the other UAVs.
-	 */
-	public static CommLink getCommLink(int numUAV) {
-
-		synchronized (lockComm) {
-			if (API.publicCommLink == null) {
-				API.publicCommLink = new AtomicReferenceArray<>(Param.numUAVs);
-				for (int i = 0; i < Param.numUAVs; i++) {
-					API.publicCommLink.set(i, new CommLink(i, Param.numUAVs, UAVParam.broadcastPort));
-				}
-			}
-		}
-
-		return API.publicCommLink.get(numUAV);
-	}
-
+
 	/**
 	 * Get the Copter instance to control the multicopter.
 	 * @param numUAV This specific UAV position in the data arrays (see documentation).

src/main/java/com/api/ArduSimTools.java

@@ -1,5 +1,6 @@
 package com.api;
 
+import com.api.communications.CommLink;
 import com.api.cpuHelper.CPUData;
 import com.api.formations.Formation;
 import com.api.formations.FormationFactory;
@@ -2769,7 +2770,7 @@ public static String getTestGlobalConfiguration() {
 		}
 		sb.append("\n").append(Text.UAV_PROTOCOL_USED).append(" ").append(ArduSimTools.selectedProtocol);
 		sb.append("\n").append(Text.COMMUNICATIONS);
-		sb.append(API.getCommLink(0).toString());
+		sb.append(CommLink.getCommLink(0).toString());
 
 		if (Param.role == ArduSim.SIMULATOR_GUI || Param.role == ArduSim.SIMULATOR_CLI) {
 			sb.append("\n").append(Text.COLLISION_PARAMETERS);

src/main/java/com/api/communications/CommLink.java

@@ -22,23 +22,43 @@ public class CommLink {
 	public static final int DATAGRAM_MAX_LENGTH = 1472; 		// (bytes) 1500-20-8 (MTU - IP - UDP)
 
 	private int numUAV;
-	private static volatile CommLinkObject publicCommLink = null;
+
+	private static volatile CommLinkObject commLinkObject = null;
 	private static final Object PUBLIC_LOCK = new Object();
 
 	private volatile boolean advertised = false;
-
-	@SuppressWarnings("unused")
-	private CommLink() {}
-
-	public CommLink(int numUAV, int numUAVs, int port) {
+
+	/**
+	 * Get the communication link needed for UAV-to-UAV communications.
+	 * @param numUAV This specific UAV position in the data arrays (see documentation).
+	 * @return Communication link used by the UAV to communicate with the other UAVs.
+	 */
+	public static CommLink getCommLink(int numUAV) {
+		return new CommLink(numUAV,Param.numUAVs,UAVParam.broadcastPort);
+	}
+
+	/**
+	 * Private constructor of CommLink in order to facilitate the singletonPattern
+	 * @param numUAV: the number of the current UAV (identifier)
+	 * @param numUAVs: total number of UAVs
+	 * @param port: port used while sending messages
+	 */
+	private CommLink(int numUAV, int numUAVs, int port) {
 		this.numUAV = numUAV;
 		synchronized(PUBLIC_LOCK) {
-			if (CommLink.publicCommLink == null) {
-				CommLink.publicCommLink = new CommLinkObject(numUAVs, port);
+			if (commLinkObject == null) {
+				commLinkObject = new CommLinkObject(numUAVs, port);
 			}
 		}
 	}
 
+	/**
+	 * Method to initialize various parameters
+	 * @param numUAVs: number of UAVs
+	 * @param carrierSensing: boolean to turn on carrier sensing
+	 * @param packetCollisionDetection: boolean to turn on packet Collision Detection
+	 * @param bufferSize: size of the buffer
+	 */
 	public static void init(int numUAVs,boolean carrierSensing, boolean packetCollisionDetection, int bufferSize){
 		CommLinkObject.carrierSensingEnabled = carrierSensing;
 		CommLinkObject.pCollisionEnabled = packetCollisionDetection;
@@ -59,6 +79,9 @@ public static void init(int numUAVs,boolean carrierSensing, boolean packetCollis
 		}
 	}
 
+	/**
+	 * Method to close all the communicationLinks
+	 */
 	public static void close(){
 		int numThreads = 2 * Param.numUAVs;
 		long now = System.currentTimeMillis();
@@ -82,7 +105,7 @@ public void sendBroadcastMessage(byte[] message) {
 				advertised = true;
 			}
 		} else {
-			CommLink.publicCommLink.sendBroadcastMessage(numUAV, message);
+			commLinkObject.sendBroadcastMessage(numUAV, message);
 		}
 	}
 
@@ -92,7 +115,7 @@ public void sendBroadcastMessage(byte[] message) {
 	 * @return The message received, or null if a fatal error with the socket happens.
 	 */
 	public byte[] receiveMessage() {
-		return CommLink.publicCommLink.receiveMessage(numUAV, 0);
+		return commLinkObject.receiveMessage(numUAV, 0);
 	}
 
 	/**
@@ -102,14 +125,14 @@ public byte[] receiveMessage() {
 	 * @return The message received, or null if a fatal error with the socket happens or the timeout is reached.
 	 */
 	public byte[] receiveMessage(int socketTimeout) {
-		return CommLink.publicCommLink.receiveMessage(numUAV, socketTimeout);
+		return commLinkObject.receiveMessage(numUAV, socketTimeout);
 	}
 
 	/** 
 	 * Generates a String representation of the communication statistics, once the experiment has finished.
 	 */
 	@Override
 	public String toString() {
-		return CommLink.publicCommLink.toString();
+		return commLinkObject.toString();
 	}
 }

src/main/java/com/api/masterslavepattern/discovery/DiscoverMasterListener.java

@@ -1,12 +1,12 @@
 package com.api.masterslavepattern.discovery;
 
 import com.api.communications.CommLink;
-import com.esotericsoftware.kryo.io.Input;
-import es.upv.grc.mapper.Location2DUTM;
-import com.setup.Text;
 import com.api.communications.InternalCommLink;
 import com.api.masterslavepattern.MSMessageID;
 import com.api.masterslavepattern.MSParam;
+import com.esotericsoftware.kryo.io.Input;
+import com.setup.Text;
+import es.upv.grc.mapper.Location2DUTM;
 
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -18,7 +18,7 @@ public class DiscoverMasterListener extends Thread {
 
 	private ConcurrentHashMap<Long, Location2DUTM> UAVsDetected;
 	private DiscoveryProgressListener listener;
-	
+
 	private InternalCommLink commLink;
 
 	@SuppressWarnings("unused")

src/main/java/com/protocols/followme/logic/FollowMeListenerThread.java

@@ -1,18 +1,17 @@
 package com.protocols.followme.logic;
 
-import com.api.API;
-import com.esotericsoftware.kryo.io.Input;
-import es.upv.grc.mapper.*;
-import com.uavController.UAVParam;
-import com.protocols.followme.pojo.Message;
-import com.setup.Param;
 import com.api.*;
 import com.api.communications.CommLink;
 import com.api.masterslavepattern.MasterSlaveHelper;
-import com.api.masterslavepattern.discovery.DiscoveryProgressListener;
 import com.api.masterslavepattern.safeTakeOff.SafeTakeOffContext;
-import com.api.masterslavepattern.safeTakeOff.SafeTakeOffListener;
+import com.esotericsoftware.kryo.io.Input;
+import com.protocols.followme.pojo.Message;
+import com.setup.Param;
 import com.setup.sim.logic.SimParam;
+import com.uavController.UAVParam;
+import es.upv.grc.mapper.Location2DGeo;
+import es.upv.grc.mapper.Location2DUTM;
+import es.upv.grc.mapper.Location3D;
 
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -51,7 +50,7 @@ public FollowMeListenerThread(int numUAV) {
 		this.isMaster = this.msHelper.isMaster();
 		this.takeOffHelper = this.copter.getSafeTakeOffHelper();
 		this.gui = API.getGUI(numUAV);
-		this.link = API.getCommLink(numUAV);
+		this.link = CommLink.getCommLink(numUAV);
 		this.inBuffer = new byte[CommLink.DATAGRAM_MAX_LENGTH];
 		this.input = new Input(inBuffer);
 		this.ardusim = API.getArduSim();
@@ -63,25 +62,21 @@ public void run() {
 			ardusim.sleep(FollowMeParam.STATE_CHANGE_TIMEOUT);
 		}
 
-		/** START PHASE */
+		// START PHASE
 		gui.logUAV(FollowMeText.START);
 		// Let the master detect slaves until the setup button is pressed
 		Map<Long, Location2DUTM> UAVsDetected = null;
 		if (this.isMaster) {
 			gui.logVerboseUAV(FollowMeText.SLAVE_START_LISTENER);
 			final AtomicInteger totalDetected = new AtomicInteger();
-			UAVsDetected = msHelper.DiscoverSlaves(new DiscoveryProgressListener() {
-
-				@Override
-				public boolean onProgressCheckActionPerformed(int numUAVs) {
-					// Just for logging purposes
-					if (numUAVs > totalDetected.get()) {
-						totalDetected.set(numUAVs);
-						gui.log(FollowMeText.MASTER_DETECTED_UAVS + numUAVs);
-					}
-					// We decide to continue when the setup button is pressed
-					return numUAVs == API.getArduSim().getNumUAVs() - 1;
+			UAVsDetected = msHelper.DiscoverSlaves(numUAVs -> {
+				// Just for logging purposes
+				if (numUAVs > totalDetected.get()) {
+					totalDetected.set(numUAVs);
+					gui.log(FollowMeText.MASTER_DETECTED_UAVS + numUAVs);
 				}
+				// We decide to continue when the setup button is pressed
+				return numUAVs == API.getArduSim().getNumUAVs() - 1;
 			});
 		} else {
 			gui.logVerboseUAV(FollowMeText.LISTENER_WAITING);
@@ -113,13 +108,7 @@ public boolean onProgressCheckActionPerformed(int numUAVs) {
 		}
 		gui.logUAV("ready to takeOff");
 		// 2. Take off all the UAVs
-		takeOffHelper.start(takeOff, new SafeTakeOffListener() {
-
-			@Override
-			public void onCompleteActionPerformed() {
-				currentState.set(SETUP_FINISHED);
-			}
-		});
+		takeOffHelper.start(takeOff, () -> currentState.set(SETUP_FINISHED));
 		while (currentState.get() < SETUP_FINISHED) {
 			ardusim.sleep(FollowMeParam.STATE_CHANGE_TIMEOUT);
 		}
@@ -193,7 +182,7 @@ public void onCompleteActionPerformed() {
 				}
 			}
 
-			/** MOVE TO LAND PHASE */
+			// MOVE TO LAND PHASE
 			if (currentState.get() == MOVE_TO_LAND) {
 				gui.logUAV(FollowMeText.MOVE_TO_LAND);
 				gui.updateProtocolState(FollowMeText.MOVE_TO_LAND);
@@ -213,12 +202,12 @@ public void onCompleteActionPerformed() {
 				moveTo.start();
 				try {
 					moveTo.join();
-				} catch (InterruptedException e) {}
+				} catch (InterruptedException ignored) {}
 				currentState.set(LANDING);
 			}
 		}
 
-		/** LANDING PHASE */
+		// LANDING PHASE
 		if (!copter.land()) {
 			gui.exit(FollowMeText.LAND_ERROR + " " + selfId);
 		}
@@ -238,7 +227,7 @@ public void onCompleteActionPerformed() {
 			}
 		}
 
-		/** FINISH PHASE */
+		// FINISH PHASE
 		gui.logUAV(FollowMeText.FINISH);
 		gui.updateProtocolState(FollowMeText.FINISH);
 		gui.logVerboseUAV(FollowMeText.LISTENER_FINISHED);

src/main/java/com/protocols/followme/logic/FollowMeTalkerThread.java

@@ -42,7 +42,7 @@ public FollowMeTalkerThread(int numUAV) {
 		this.ardusim = API.getArduSim();
 		this.copter = API.getCopter(numUAV);
 		this.gui = API.getGUI(numUAV);
-		this.link = API.getCommLink(numUAV);
+		this.link = CommLink.getCommLink(numUAV);
 		this.outBuffer = new byte[CommLink.DATAGRAM_MAX_LENGTH];
 		this.output = new Output(outBuffer);
 
@@ -86,7 +86,7 @@ public void run() {
 			ardusim.sleep(FollowMeParam.STATE_CHANGE_TIMEOUT);
 		}
 
-		/** LANDING PHASE */
+		// LANDING PHASE
 		gui.logVerboseUAV(FollowMeText.MASTER_SEND_LAND);
 		output.reset();
 		output.writeShort(Message.LAND);
@@ -112,7 +112,7 @@ public void run() {
 			ardusim.sleep(FollowMeParam.STATE_CHANGE_TIMEOUT);
 		}
 
-		/** FINISH PHASE */
+		// FINISH PHASE
 		gui.logVerboseUAV(FollowMeText.TALKER_FINISHED);
 	}
 

src/main/java/com/protocols/mbcap/logic/BeaconingThread.java

@@ -64,7 +64,7 @@ public BeaconingThread(int numUAV) {
 		this.impactLocationUTM = MBCAPParam.impactLocationUTM[numUAV];
 
 		this.numUAV = numUAV;
-		this.link = API.getCommLink(numUAV);
+		this.link = CommLink.getCommLink(numUAV);
 		this.outBuffer = new byte[CommLink.DATAGRAM_MAX_LENGTH];
 		this.output = new Output(outBuffer);
 		this.copter = API.getCopter(numUAV);

src/main/java/com/protocols/mbcap/logic/MBCAPPCCompanionListener.java

@@ -1,9 +1,7 @@
 package com.protocols.mbcap.logic;
 
-import com.esotericsoftware.kryo.io.Input;
-
-import com.api.API;
 import com.api.communications.CommLink;
+import com.esotericsoftware.kryo.io.Input;
 import com.protocols.mbcap.gui.MBCAPPCCompanionDialog;
 import com.protocols.mbcap.pojo.Beacon;
 
@@ -24,7 +22,7 @@ private MBCAPPCCompanionListener() {}
 
 	public MBCAPPCCompanionListener(MBCAPPCCompanionDialog dialog) {
 		this.dialog = dialog;
-		this.link = API.getCommLink(0);
+		this.link = CommLink.getCommLink(0);
 		this.inBuffer = new byte[CommLink.DATAGRAM_MAX_LENGTH];
 		this.input = new Input(inBuffer);
 	}

src/main/java/com/protocols/mbcap/logic/ReceiverThread.java

@@ -30,7 +30,7 @@ private ReceiverThread() {}
 	public ReceiverThread(int numUAV) {
 		this.beacons = MBCAPParam.beacons[numUAV];
 		this.numUAV = numUAV;
-		this.link = API.getCommLink(numUAV);
+		this.link = CommLink.getCommLink(numUAV);
 		this.inBuffer = new byte[CommLink.DATAGRAM_MAX_LENGTH];
 		this.input = new Input(inBuffer);
 		this.copter = API.getCopter(numUAV);

src/main/java/com/protocols/muscop/logic/MUSCOPListenerThread.java

@@ -71,7 +71,7 @@ public MUSCOPListenerThread(int numUAV) {
 		this.gui = API.getGUI(numUAV);
 		this.inBuffer = new byte[CommLink.DATAGRAM_MAX_LENGTH];
 		this.input = new Input(inBuffer);
-		this.link = API.getCommLink(numUAV);
+		this.link = CommLink.getCommLink(numUAV);
 		this.ardusim = API.getArduSim();
 		this.msHelper = this.copter.getMasterSlaveHelper();
 		this.isMaster = this.msHelper.isMaster();