[CORD-1433] DHCP Relay Store

Change-Id: Ibb92e07d570c631ea35ce1b826e4ee630ba8f5db
diff --git a/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/store/DhcpRelayStoreEvent.java b/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/store/DhcpRelayStoreEvent.java
new file mode 100644
index 0000000..bca3df3
--- /dev/null
+++ b/apps/dhcprelay/src/main/java/org/onosproject/dhcprelay/store/DhcpRelayStoreEvent.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2017-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.dhcprelay.store;
+
+
+import org.onosproject.event.AbstractEvent;
+
+/**
+ * Event class for DHCP relay store.
+ */
+public class DhcpRelayStoreEvent extends AbstractEvent<DhcpRelayStoreEvent.Type, DhcpRecord> {
+
+    /**
+     * Types of the event.
+     */
+    public enum Type {
+        /**
+         * A DHCP record has been created or updated.
+         */
+        UPDATED,
+
+        /**
+         * A DHCP record has been removed.
+         */
+        REMOVED
+    }
+
+    /**
+     * Creates a DHCP relay store event by given information.
+     *
+     * @param type the type of event
+     * @param subject the DHCP record of this event
+     */
+    protected DhcpRelayStoreEvent(Type type, DhcpRecord subject) {
+        super(type, subject);
+    }
+}