[ONOS-4226]Service function group class added for sf statistics

Change-Id: I93fa832b8935c065a2384581daa55d304ffe2123
diff --git a/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/ServiceFunctionGroup.java b/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/ServiceFunctionGroup.java
new file mode 100644
index 0000000..fae8bb6
--- /dev/null
+++ b/apps/vtn/vtnrsc/src/main/java/org/onosproject/vtnrsc/ServiceFunctionGroup.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.onosproject.vtnrsc;
+
+import static com.google.common.base.MoreObjects.toStringHelper;
+
+import java.util.Map;
+import java.util.Objects;
+
+import com.google.common.collect.ImmutableMap;
+
+/**
+ * Implementation of ServiceFunctionGroup class.
+ */
+public final class ServiceFunctionGroup {
+
+    private final String name;
+    private final String description;
+    private final Map<PortPairId, Integer> portPairLoadMap;
+
+    /**
+     * Creates an instance of service function group.
+     *
+     * @param name name of port pair
+     * @param description description of port pair
+     * @param portPairLoadMap map of port pair id and its load
+     */
+    public ServiceFunctionGroup(String name, String description,
+                                Map<PortPairId, Integer> portPairLoadMap) {
+        this.name = name;
+        this.description = description;
+        this.portPairLoadMap = portPairLoadMap;
+    }
+
+    /**
+     * Returns name of service function group.
+     *
+     * @return name of service function group
+     */
+    public String name() {
+        return name;
+    }
+
+    /**
+     * Returns description of service function group.
+     *
+     * @return description of service function group.
+     */
+    public String description() {
+        return description;
+    }
+
+    /**
+     * Returns port pair load map.
+     *
+     * @return port pair load map
+     */
+    public Map<PortPairId, Integer> portPairLoadMap() {
+        return ImmutableMap.copyOf(portPairLoadMap);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name, description, portPairLoadMap);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj instanceof ServiceFunctionGroup) {
+            ServiceFunctionGroup that = (ServiceFunctionGroup) obj;
+            return Objects.equals(name, that.name()) &&
+                    Objects.equals(description, that.description()) &&
+                    Objects.equals(portPairLoadMap, that.portPairLoadMap());
+        }
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper(this)
+                .add("name", name)
+                .add("description", description)
+                .add("portPairLoadMap", portPairLoadMap)
+                .toString();
+    }
+}