[ONOS-5076] YANG data tree Builder
Change-Id: I25160b651c26e614d29d7fad85e63f77a262d77c
diff --git a/apps/yms/app/src/main/java/org/onosproject/yms/app/ydt/YdtExtendedListener.java b/apps/yms/app/src/main/java/org/onosproject/yms/app/ydt/YdtExtendedListener.java
new file mode 100644
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+/*
+ * 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.yms.app.ydt;
+
+
+import org.onosproject.yms.ydt.YdtListener;
+
+/**
+ * Abstraction of an entity which provide call back methods which are called
+ * by YDT extended walker while walking the YANG data tree.
+ * <p>
+ * This interface needs to be implemented by protocol implementing listener's
+ * based call backs while YDT walk, and update application specific information
+ * in data node.
+ */
+public interface YdtExtendedListener extends YdtListener {
+
+ /**
+ * YANG data tree node's entry, it will be called during a node entry.
+ * <p>
+ * All the related information about the node can be obtain from the YDT
+ * context. Also it can be used to maintain / query application specific
+ * information.
+ *
+ * @param ydtExtendedContext YANG data tree context
+ */
+ void enterYdtNode(YdtExtendedContext ydtExtendedContext);
+
+ /**
+ * YANG data tree node's exit, it will be called during a node exit.
+ * <p>
+ * All the related information about the node can be obtain from the YDT
+ * context. Also it can be used to maintain / query application specific
+ * information.
+ *
+ * @param ydtExtendedContext YANG data tree context
+ */
+ void exitYdtNode(YdtExtendedContext ydtExtendedContext);
+}