api: InternalIdentity interface that provides contract to have getId

Adds new interface that would maintain contract that extending Interface
or implementing class will have the getId() method to get Internal Id

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>

api/src/org/apache/cloudstack/api/InternalIdentity.java

@@ -0,0 +1,26 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.apache.cloudstack.api;
+
+// This interface is a contract that getId() will give the internal
+// ID of an entity which extends this interface
+// Any class having an internal ID in db table/schema should extend this
+// For example, all ControlledEntity, OwnedBy would have an internal ID
+
+public interface InternalIdentity {
+    long getId();
+}