[SEBA-37] Added 11 Statistics counters for Accounting Server operations

Change-Id: I7dda193129e5dffe62907775aaf8dfdc5b3f1bf1
diff --git a/api/src/main/java/org/opencord/aaa/AuthenticationStatisticsService.java b/api/src/main/java/org/opencord/aaa/AuthenticationStatisticsService.java
new file mode 100644
index 0000000..bdb9f2d
--- /dev/null
+++ b/api/src/main/java/org/opencord/aaa/AuthenticationStatisticsService.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.opencord.aaa;
+
+import org.onosproject.event.ListenerService;
+
+/**
+ * Service for interacting with accounting module.
+ */
+
+public interface AuthenticationStatisticsService extends
+        ListenerService<AuthenticationStatisticsEvent, AuthenticationStatisticsEventListener> {
+
+    /**
+     * Returns AaaStatistics object.
+     *
+     * @return AaaStatistics
+    */
+    public AaaStatistics getAaaStats();
+
+    /**
+     * Returns AuthenticationStatisticsDelegate object.
+     *
+     * @return AuthenticationStatisticsDelegate
+    */
+    public AuthenticationStatisticsDelegate getStatsDelegate();
+
+    /**
+     * Handle the roundTrip time of Radius Packet.
+     *
+     * @param identifier identifier of incoming radius packet
+    */
+    public void handleRoundtripTime(byte identifier);
+
+    /**
+     * Calculate average roundTrip time of multiple Packets.
+    */
+    public void calculatePacketRoundtripTime();
+
+    /**
+     * Put the identifier value to map.
+     *
+     * @param identifier identifier of incoming radius packet
+    */
+    public void putOutgoingIdentifierToMap(byte identifier);
+}