YMS broker and Notification handler

Change-Id: Ic3659b2c2ad26ea2db1f03725b4883f19db2cc41
diff --git a/apps/yms/api/src/main/java/org/onosproject/yms/ynh/YangNotification.java b/apps/yms/api/src/main/java/org/onosproject/yms/ynh/YangNotification.java
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+/*
+ * Copyright 2015-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.yms.ynh;
+
+import org.onosproject.yms.ydt.YdtContext;
+
+/**
+ * Represents YANG notification which is a subject of YANG based event.
+ *
+ * YMS add themselves as a listener to applications. Application sends
+ * their notification in YANG utils generated notification. YMS obtains
+ * the module/sub-module schema tree in which this notification is contained
+ * and then convert this data to an abstract tree notation (YDT) with root
+ * node as the logical node with name "yangnotification" it contains
+ * module/sub-module node in which notification is contained.
+ * It sends the same to all the protocol who has added them as a listener
+ * as a YANG notification.
+ *
+ * This class represents YANG notification which contains the
+ * notification context in abstract tree notation.
+ */
+public class YangNotification {
+
+    /**
+     * YANG notification in form of abstract tree notation (YDT)
+     * Root node of notification root context will be logical node with
+     * name as "yangnotification", it contains module/sub-module node
+     * in which notification is contained.
+     */
+    YdtContext notificationRootContext;
+
+    /**
+     * Creates an instance of YANG notification subject.
+     *
+     * @param notificationContext logical root node with name as
+     *                            "yangnotification"
+     */
+    public YangNotification(YdtContext notificationContext) {
+        this.notificationRootContext = notificationContext;
+    }
+
+    /**
+     * Assign the YANG modeled notification data.
+     *
+     * @param notificationRootContext YANG data tree containing the data for
+     *                                the notification
+     */
+    public void setNotificationRootContext(YdtContext notificationRootContext) {
+        this.notificationRootContext = notificationRootContext;
+    }
+
+    /**
+     * Returns YANG notification data.
+     *
+     * @return YANG data tree containing the data for the notification
+     */
+    public YdtContext getNotificationRootContext() {
+        return notificationRootContext;
+    }
+}