Server device driver extensions

 * Additional behaviours implemented
    * BasicSystemOperations
    * DeviceHandshaker
    * InterfaceConfig
    * PortAdmin
    * QueueConfig
    * TableStatisticsDiscovery
    * DeviceSystemStatisticsQuery
 * New device abstractions on CPU cache and main memory
 * Additional statistics (main memory)
 * New UI with Memory statistics (based on the old gui)
 * Constants decoupled from implementations
 * More builders used for interface implementations
 * Style fixes and refactoring

Change-Id: Ie54ed0fb4760456cfd6339c74b36486dd3c20f87
Signed-off-by: Georgios Katsikas <katsikas.gp@gmail.com>
diff --git a/drivers/server/src/main/java/org/onosproject/drivers/server/devices/nic/RssRxFilterValue.java b/drivers/server/src/main/java/org/onosproject/drivers/server/devices/nic/RssRxFilterValue.java
index 2d54a81..f43a6db 100644
--- a/drivers/server/src/main/java/org/onosproject/drivers/server/devices/nic/RssRxFilterValue.java
+++ b/drivers/server/src/main/java/org/onosproject/drivers/server/devices/nic/RssRxFilterValue.java
@@ -13,11 +13,13 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.onosproject.drivers.server.devices.nic;
 
 import java.util.Objects;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static org.onosproject.drivers.server.Constants.MSG_NIC_FLOW_FILTER_RSS_NEGATIVE;
 
 /**
  * A Receice-Side Scaling (RSS)-based Rx filter value.
@@ -72,7 +74,7 @@
      * @param rssHash the RSS hash
      */
     public void setValue(int rssHash) {
-        checkArgument(rssHash >= 0, "Invalid RSS Rx filter " + rssHash);
+        checkArgument(rssHash >= 0, MSG_NIC_FLOW_FILTER_RSS_NEGATIVE);
         this.rssHash = rssHash;
     }