code adjustment according to reviewer's suggestion: MAC final type, indentation, exception handler
diff --git a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ArpMessage.java b/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ArpMessage.java
index dd159fe..6ce5ade 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ArpMessage.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/proxyarp/ArpMessage.java
@@ -20,10 +20,10 @@
 	private final byte[] packetData;
 	
 	//ARP reply message needs MAC info
-	private  MACAddress mac;
-	//only send the ARP request message to the device attachment needs the attachement swith and port. 
-	private long outSwitch=-1; 
-	private short outPort=-1;
+	private final MACAddress mac;
+	//only send the ARP request message to the device attachment needs the attachment switch and port. 
+	private final long outSwitch; 
+	private final short outPort;
 	
 	
 	private final List<SwitchPort> switchPorts = new ArrayList<SwitchPort>();
@@ -38,19 +38,28 @@
 		this.type = type;
 		this.forAddress = address;
 		this.packetData = eth;
+		this.mac = null;
+		this.outSwitch = -1;
+		this.outPort = -1;
 	}
 	
 	private ArpMessage(Type type, InetAddress address) {
 		this.type = type;
 		this.forAddress = address;
 		this.packetData = null;
+		this.mac = null;
+		this.outSwitch = -1;
+		this.outPort = -1;
+		
 	}
 	// the ARP reply message with MAC
 	private ArpMessage(Type type, InetAddress address, MACAddress mac) {
 		this.type = type;
 		this.forAddress = address;
 		this.packetData = null;
-		this.mac=mac;
+		this.mac = mac;
+		this.outSwitch = -1;
+		this.outPort = -1;
 	}
 	
 	// construct ARP request message with attachment switch and port
@@ -58,9 +67,10 @@
 			long outSwitch, short outPort) {
 		this.type = type;
 		this.forAddress = address;
-		this.packetData = arpRequest; 
-		this.setOutSwitch(outSwitch); 
-		this.setOutPort(outPort);	
+		this.packetData = arpRequest; 	
+		this.mac = null;
+		this.outSwitch = outSwitch; 
+		this.outPort = outPort;	
 	}
 
 	public static ArpMessage newRequest(InetAddress forAddress, byte[] arpRequest) {
@@ -73,12 +83,12 @@
 	//ARP reply message with MAC
 	public static ArpMessage newReply(InetAddress forAddress, MACAddress mac) {
 		return new ArpMessage(Type.REPLY, forAddress, mac);
-		
+
 	}
 	//ARP reqsuest message with attachment switch and port
 	public static ArpMessage newRequest(InetAddress forAddress, byte[] arpRequest, long outSwitch, short outPort ) {
 		return new ArpMessage(Type.REQUEST, forAddress, arpRequest, outSwitch, outPort);
-		
+
 	}
 
 	public Type getType() {
@@ -100,15 +110,8 @@
 		return outSwitch;
 	}
 
-	public void setOutSwitch(long outSwitch) {
-		this.outSwitch = outSwitch;
-	}
-
 	public short getOutPort() {
 		return outPort;
 	}
 
-	public void setOutPort(short outPort) {
-		this.outPort = outPort;
-	}
 }