Fixed NIC name to port number inconsistencies in server driver

This patch fixes some weak assumptions regarding the way the
server device driver maps NIC names and port numbers.
Also, some necessary refactoring and stdout message fixes are
committed.

Addressed comments from ONOS developers

Change-Id: I6730d971ddf8d4fe97c2d3bef75f1432e7a4592e
Signed-off-by: Georgios Katsikas <katsikas.gp@gmail.com>
diff --git a/drivers/server/src/main/java/org/onosproject/drivers/server/impl/devices/DefaultRestServerSBDevice.java b/drivers/server/src/main/java/org/onosproject/drivers/server/impl/devices/DefaultRestServerSBDevice.java
index 410a5b4..cc2e541 100644
--- a/drivers/server/src/main/java/org/onosproject/drivers/server/impl/devices/DefaultRestServerSBDevice.java
+++ b/drivers/server/src/main/java/org/onosproject/drivers/server/impl/devices/DefaultRestServerSBDevice.java
@@ -25,6 +25,7 @@
 import org.onlab.packet.IpAddress;
 
 import com.google.common.base.MoreObjects;
+import com.google.common.base.Strings;
 import com.google.common.collect.Lists;
 
 import java.util.Objects;
@@ -91,6 +92,36 @@
     }
 
     @Override
+    public long portNumberFromName(String portName) {
+        if (Strings.isNullOrEmpty(portName)) {
+            return -1;
+        }
+
+        for (NicDevice nic : this.nics) {
+            if (nic.name().equals(portName)) {
+                return nic.portNumber();
+            }
+        }
+
+        return -1;
+    }
+
+    @Override
+    public String portNameFromNumber(long portNumber) {
+        if (portNumber < 0) {
+            return "";
+        }
+
+        for (NicDevice nic : this.nics) {
+            if (nic.portNumber() == portNumber) {
+                return nic.name();
+            }
+        }
+
+        return "";
+    }
+
+    @Override
     public String toString() {
         return MoreObjects.toStringHelper(this)
                 .omitNullValues()