diff --git a/utils/yangutils/pom.xml b/utils/yangutils/pom.xml
index 6b98ea5..16490c2 100644
--- a/utils/yangutils/pom.xml
+++ b/utils/yangutils/pom.xml
@@ -152,11 +152,43 @@
                 <configuration>
                     <sourceDirectory>src/main/resources</sourceDirectory>
                     <outputDirectory>target/generated-sources/org/onosproject/yangutils/parser/antlrgencode</outputDirectory>
-                    <visitor>true</visitor>
+                    <visitor>false</visitor>
                     <listener>true</listener>
                 </configuration>
             </plugin>
             <plugin>
+                <artifactId>maven-clean-plugin</artifactId>
+                <version>3.0.0</version>
+                <executions>
+                    <execution>
+                        <id>Deleting auto-generated listener interfaces</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>clean</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <configuration>
+                    <excludeDefaultDirectories>true</excludeDefaultDirectories>
+                    <filesets>
+                        <fileset>
+                            <directory>target</directory>
+                            <followSymlinks>false</followSymlinks>
+                            <useDefaultExcludes>true</useDefaultExcludes>
+                            <excludes>
+                                <exclude>**/generated-sources/org/onosproject/yangutils/parser/antlrgencode/GeneratedYangLexer.java</exclude>
+                                <exclude>**/generated-sources/org/onosproject/yangutils/parser/antlrgencode/GeneratedYang.tokens</exclude>
+                                <exclude>**/generated-sources/org/onosproject/yangutils/parser/antlrgencode/GeneratedYangParser.java</exclude>
+                                <exclude>**/generated-sources/org/onosproject/yangutils/parser/antlrgencode/GeneratedYangLexer.tokens</exclude>
+                                <exclude>**/generated-sources/org/onosproject/yangutils/parser/antlrgencode/YangLexer.java</exclude>
+                                <exclude>**/generated-sources/org/onosproject/yangutils/parser/antlrgencode/YangLexer.tokens</exclude>
+                            </excludes>
+                        </fileset>
+                    </filesets>
+                    <verbose>true</verbose>
+                </configuration>
+            </plugin>
+            <plugin>
                 <groupId>org.codehaus.mojo</groupId>
                 <artifactId>build-helper-maven-plugin</artifactId>
                 <version>1.10</version>
@@ -176,16 +208,6 @@
                 </executions>
             </plugin>
             <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-javadoc-plugin</artifactId>
-                <version>2.10.3</version>
-                <configuration>
-                    <excludePackageNames>
-                        *.org.onosproject.yangutils.parser.antlrgencode
-                    </excludePackageNames>
-                </configuration>
-            </plugin>
-            <plugin>
                 <groupId>org.apache.felix</groupId>
                 <artifactId>maven-bundle-plugin</artifactId>
                 <extensions>true</extensions>
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/YangUtilsParser.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/YangUtilsParser.java
index 19d9f3b..36e9c1d 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/YangUtilsParser.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/YangUtilsParser.java
@@ -29,9 +29,10 @@
     /**
      * It is an entry function to initiate the YANG file parsing.
      *
-     * @param file input YANG file
-     * @return YangNode root node of the data model tree
-     * @throws ParserException when fails to get the data model
+     * @param file input YANG file.
+     * @return YangNode root node of the data model tree.
+     * @throws ParserException when fails to get the data model.
+     * @throws IOException when there is an exception in IO operation.
      */
     YangNode getDataModel(String file) throws IOException, ParserException;
 }
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/antlrgencode/GeneratedYangListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/antlrgencode/GeneratedYangListener.java
new file mode 100644
index 0000000..9bb54aa
--- /dev/null
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/antlrgencode/GeneratedYangListener.java
@@ -0,0 +1,1706 @@
+// Generated from GeneratedYang.g4 by ANTLR 4.5
+/*
+ * Copyright 2016 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.yangutils.parser.antlrgencode;
+
+import org.antlr.v4.runtime.tree.ParseTreeListener;
+
+/**
+ * ANTLR interfaces to be implemented by listener to traverse the parse tree.
+ */
+public interface GeneratedYangListener extends ParseTreeListener {
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * yangfile.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterYangfile(GeneratedYangParser.YangfileContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * yangfile.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitYangfile(GeneratedYangParser.YangfileContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * moduleStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterModuleStatement(GeneratedYangParser.ModuleStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * moduleStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitModuleStatement(GeneratedYangParser.ModuleStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * moduleBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterModuleBody(GeneratedYangParser.ModuleBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * moduleBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitModuleBody(GeneratedYangParser.ModuleBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * moduleHeaderStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterModuleHeaderStatement(GeneratedYangParser.ModuleHeaderStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * moduleHeaderStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitModuleHeaderStatement(GeneratedYangParser.ModuleHeaderStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * linkageStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterLinkageStatements(GeneratedYangParser.LinkageStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * linkageStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitLinkageStatements(GeneratedYangParser.LinkageStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * metaStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterMetaStatements(GeneratedYangParser.MetaStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * metaStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitMetaStatements(GeneratedYangParser.MetaStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRevisionStatements(GeneratedYangParser.RevisionStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRevisionStatements(GeneratedYangParser.RevisionStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * bodyStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBodyStatements(GeneratedYangParser.BodyStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * bodyStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBodyStatements(GeneratedYangParser.BodyStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * yangVersionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterYangVersionStatement(GeneratedYangParser.YangVersionStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * yangVersionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitYangVersionStatement(GeneratedYangParser.YangVersionStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * namespaceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterNamespaceStatement(GeneratedYangParser.NamespaceStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * namespaceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitNamespaceStatement(GeneratedYangParser.NamespaceStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * prefixStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterPrefixStatement(GeneratedYangParser.PrefixStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * prefixStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitPrefixStatement(GeneratedYangParser.PrefixStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * importStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterImportStatement(GeneratedYangParser.ImportStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * importStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitImportStatement(GeneratedYangParser.ImportStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * importStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterImportStatementBody(GeneratedYangParser.ImportStatementBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * importStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitImportStatementBody(GeneratedYangParser.ImportStatementBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionDateStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRevisionDateStatement(GeneratedYangParser.RevisionDateStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionDateStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRevisionDateStatement(GeneratedYangParser.RevisionDateStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * includeStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterIncludeStatement(GeneratedYangParser.IncludeStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * includeStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitIncludeStatement(GeneratedYangParser.IncludeStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * organizationStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterOrganizationStatement(GeneratedYangParser.OrganizationStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * organizationStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitOrganizationStatement(GeneratedYangParser.OrganizationStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * contactStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterContactStatement(GeneratedYangParser.ContactStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * contactStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitContactStatement(GeneratedYangParser.ContactStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * descriptionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDescriptionStatement(GeneratedYangParser.DescriptionStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * descriptionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDescriptionStatement(GeneratedYangParser.DescriptionStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * referenceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterReferenceStatement(GeneratedYangParser.ReferenceStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * referenceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitReferenceStatement(GeneratedYangParser.ReferenceStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRevisionStatement(GeneratedYangParser.RevisionStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRevisionStatement(GeneratedYangParser.RevisionStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRevisionStatementBody(GeneratedYangParser.RevisionStatementBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * revisionStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRevisionStatementBody(GeneratedYangParser.RevisionStatementBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * subModuleStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterSubModuleStatement(GeneratedYangParser.SubModuleStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * subModuleStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitSubModuleStatement(GeneratedYangParser.SubModuleStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * submoduleBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterSubmoduleBody(GeneratedYangParser.SubmoduleBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * submoduleBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitSubmoduleBody(GeneratedYangParser.SubmoduleBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * submoduleHeaderStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterSubmoduleHeaderStatement(GeneratedYangParser.SubmoduleHeaderStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * submoduleHeaderStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitSubmoduleHeaderStatement(GeneratedYangParser.SubmoduleHeaderStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * belongstoStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBelongstoStatement(GeneratedYangParser.BelongstoStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * belongstoStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBelongstoStatement(GeneratedYangParser.BelongstoStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * belongstoStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBelongstoStatementBody(GeneratedYangParser.BelongstoStatementBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * belongstoStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBelongstoStatementBody(GeneratedYangParser.BelongstoStatementBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * extensionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterExtensionStatement(GeneratedYangParser.ExtensionStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * extensionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitExtensionStatement(GeneratedYangParser.ExtensionStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * extensionBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterExtensionBody(GeneratedYangParser.ExtensionBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * extensionBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitExtensionBody(GeneratedYangParser.ExtensionBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * argumentStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterArgumentStatement(GeneratedYangParser.ArgumentStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * argumentStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitArgumentStatement(GeneratedYangParser.ArgumentStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * argumentBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterArgumentBody(GeneratedYangParser.ArgumentBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * argumentBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitArgumentBody(GeneratedYangParser.ArgumentBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * yinElementStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterYinElementStatement(GeneratedYangParser.YinElementStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * yinElementStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitYinElementStatement(GeneratedYangParser.YinElementStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * identityStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterIdentityStatement(GeneratedYangParser.IdentityStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * identityStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitIdentityStatement(GeneratedYangParser.IdentityStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * identityBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterIdentityBody(GeneratedYangParser.IdentityBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * identityBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitIdentityBody(GeneratedYangParser.IdentityBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * baseStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBaseStatement(GeneratedYangParser.BaseStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * baseStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBaseStatement(GeneratedYangParser.BaseStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * featureStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterFeatureStatement(GeneratedYangParser.FeatureStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * featureStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitFeatureStatement(GeneratedYangParser.FeatureStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * featureBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterFeatureBody(GeneratedYangParser.FeatureBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * featureBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitFeatureBody(GeneratedYangParser.FeatureBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * dataDefStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDataDefStatement(GeneratedYangParser.DataDefStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * dataDefStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDataDefStatement(GeneratedYangParser.DataDefStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * ifFeatureStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterIfFeatureStatement(GeneratedYangParser.IfFeatureStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * ifFeatureStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitIfFeatureStatement(GeneratedYangParser.IfFeatureStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * unitsStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterUnitsStatement(GeneratedYangParser.UnitsStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * unitsStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitUnitsStatement(GeneratedYangParser.UnitsStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * typedefStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterTypedefStatement(GeneratedYangParser.TypedefStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * typedefStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitTypedefStatement(GeneratedYangParser.TypedefStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * typeStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterTypeStatement(GeneratedYangParser.TypeStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * typeStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitTypeStatement(GeneratedYangParser.TypeStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * typeBodyStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterTypeBodyStatements(GeneratedYangParser.TypeBodyStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * typeBodyStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitTypeBodyStatements(GeneratedYangParser.TypeBodyStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * numericalRestrictions.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterNumericalRestrictions(GeneratedYangParser.NumericalRestrictionsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * numericalRestrictions.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitNumericalRestrictions(GeneratedYangParser.NumericalRestrictionsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * rangeStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRangeStatement(GeneratedYangParser.RangeStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * rangeStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRangeStatement(GeneratedYangParser.RangeStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * commonStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterCommonStatements(GeneratedYangParser.CommonStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * commonStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitCommonStatements(GeneratedYangParser.CommonStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * stringRestrictions.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterStringRestrictions(GeneratedYangParser.StringRestrictionsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * stringRestrictions.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitStringRestrictions(GeneratedYangParser.StringRestrictionsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * lengthStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterLengthStatement(GeneratedYangParser.LengthStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * lengthStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitLengthStatement(GeneratedYangParser.LengthStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * patternStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterPatternStatement(GeneratedYangParser.PatternStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * patternStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitPatternStatement(GeneratedYangParser.PatternStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * defaultStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDefaultStatement(GeneratedYangParser.DefaultStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * defaultStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDefaultStatement(GeneratedYangParser.DefaultStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * enumSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterEnumSpecification(GeneratedYangParser.EnumSpecificationContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * enumSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitEnumSpecification(GeneratedYangParser.EnumSpecificationContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * enumStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterEnumStatement(GeneratedYangParser.EnumStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * enumStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitEnumStatement(GeneratedYangParser.EnumStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * enumStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterEnumStatementBody(GeneratedYangParser.EnumStatementBodyContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * enumStatementBody.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitEnumStatementBody(GeneratedYangParser.EnumStatementBodyContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * leafrefSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterLeafrefSpecification(GeneratedYangParser.LeafrefSpecificationContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * leafrefSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitLeafrefSpecification(GeneratedYangParser.LeafrefSpecificationContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * pathStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterPathStatement(GeneratedYangParser.PathStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * pathStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitPathStatement(GeneratedYangParser.PathStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * requireInstanceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRequireInstanceStatement(GeneratedYangParser.RequireInstanceStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * requireInstanceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRequireInstanceStatement(GeneratedYangParser.RequireInstanceStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * instanceIdentifierSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterInstanceIdentifierSpecification(GeneratedYangParser.InstanceIdentifierSpecificationContext
+                                              currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * instanceIdentifierSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitInstanceIdentifierSpecification(GeneratedYangParser.InstanceIdentifierSpecificationContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * identityrefSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterIdentityrefSpecification(GeneratedYangParser.IdentityrefSpecificationContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * identityrefSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitIdentityrefSpecification(GeneratedYangParser.IdentityrefSpecificationContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * unionSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterUnionSpecification(GeneratedYangParser.UnionSpecificationContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * unionSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitUnionSpecification(GeneratedYangParser.UnionSpecificationContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * bitsSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBitsSpecification(GeneratedYangParser.BitsSpecificationContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * bitsSpecification.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBitsSpecification(GeneratedYangParser.BitsSpecificationContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * bitStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBitStatement(GeneratedYangParser.BitStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * bitStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBitStatement(GeneratedYangParser.BitStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * bitBodyStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterBitBodyStatement(GeneratedYangParser.BitBodyStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * bitBodyStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitBitBodyStatement(GeneratedYangParser.BitBodyStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * positionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterPositionStatement(GeneratedYangParser.PositionStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * positionStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitPositionStatement(GeneratedYangParser.PositionStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * statusStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterStatusStatement(GeneratedYangParser.StatusStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * statusStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitStatusStatement(GeneratedYangParser.StatusStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * configStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterConfigStatement(GeneratedYangParser.ConfigStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * configStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitConfigStatement(GeneratedYangParser.ConfigStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * mandatoryStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterMandatoryStatement(GeneratedYangParser.MandatoryStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * mandatoryStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitMandatoryStatement(GeneratedYangParser.MandatoryStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * presenceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterPresenceStatement(GeneratedYangParser.PresenceStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * presenceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitPresenceStatement(GeneratedYangParser.PresenceStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * orderedByStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterOrderedByStatement(GeneratedYangParser.OrderedByStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * orderedByStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitOrderedByStatement(GeneratedYangParser.OrderedByStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * mustStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterMustStatement(GeneratedYangParser.MustStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * mustStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitMustStatement(GeneratedYangParser.MustStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * errorMessageStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterErrorMessageStatement(GeneratedYangParser.ErrorMessageStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * errorMessageStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitErrorMessageStatement(GeneratedYangParser.ErrorMessageStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * errorAppTagStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterErrorAppTagStatement(GeneratedYangParser.ErrorAppTagStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * errorAppTagStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitErrorAppTagStatement(GeneratedYangParser.ErrorAppTagStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * minElementsStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterMinElementsStatement(GeneratedYangParser.MinElementsStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * minElementsStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitMinElementsStatement(GeneratedYangParser.MinElementsStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * maxElementsStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterMaxElementsStatement(GeneratedYangParser.MaxElementsStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * maxElementsStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitMaxElementsStatement(GeneratedYangParser.MaxElementsStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * maxValueArgument.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterMaxValueArgument(GeneratedYangParser.MaxValueArgumentContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * maxValueArgument.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitMaxValueArgument(GeneratedYangParser.MaxValueArgumentContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * valueStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterValueStatement(GeneratedYangParser.ValueStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * valueStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitValueStatement(GeneratedYangParser.ValueStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * groupingStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterGroupingStatement(GeneratedYangParser.GroupingStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * groupingStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitGroupingStatement(GeneratedYangParser.GroupingStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * containerStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterContainerStatement(GeneratedYangParser.ContainerStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * containerStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitContainerStatement(GeneratedYangParser.ContainerStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * leafStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterLeafStatement(GeneratedYangParser.LeafStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * leafStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitLeafStatement(GeneratedYangParser.LeafStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * leafListStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterLeafListStatement(GeneratedYangParser.LeafListStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * leafListStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitLeafListStatement(GeneratedYangParser.LeafListStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * listStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterListStatement(GeneratedYangParser.ListStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * listStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitListStatement(GeneratedYangParser.ListStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * keyStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterKeyStatement(GeneratedYangParser.KeyStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * keyStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitKeyStatement(GeneratedYangParser.KeyStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * uniqueStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterUniqueStatement(GeneratedYangParser.UniqueStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * uniqueStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitUniqueStatement(GeneratedYangParser.UniqueStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * choiceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterChoiceStatement(GeneratedYangParser.ChoiceStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * choiceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitChoiceStatement(GeneratedYangParser.ChoiceStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * shortCaseStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterShortCaseStatement(GeneratedYangParser.ShortCaseStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * shortCaseStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitShortCaseStatement(GeneratedYangParser.ShortCaseStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * caseStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterCaseStatement(GeneratedYangParser.CaseStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * caseStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitCaseStatement(GeneratedYangParser.CaseStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * usesStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterUsesStatement(GeneratedYangParser.UsesStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * usesStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitUsesStatement(GeneratedYangParser.UsesStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineStatement(GeneratedYangParser.RefineStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineStatement(GeneratedYangParser.RefineStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineContainerStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineContainerStatements(GeneratedYangParser.RefineContainerStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineContainerStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineContainerStatements(GeneratedYangParser.RefineContainerStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineLeafStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineLeafStatements(GeneratedYangParser.RefineLeafStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineLeafStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineLeafStatements(GeneratedYangParser.RefineLeafStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineLeafListStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineLeafListStatements(GeneratedYangParser.RefineLeafListStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineLeafListStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineLeafListStatements(GeneratedYangParser.RefineLeafListStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineListStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineListStatements(GeneratedYangParser.RefineListStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineListStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineListStatements(GeneratedYangParser.RefineListStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineChoiceStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineChoiceStatements(GeneratedYangParser.RefineChoiceStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineChoiceStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineChoiceStatements(GeneratedYangParser.RefineChoiceStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * refineCaseStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRefineCaseStatements(GeneratedYangParser.RefineCaseStatementsContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * refineCaseStatements.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRefineCaseStatements(GeneratedYangParser.RefineCaseStatementsContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * usesAugmentStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterUsesAugmentStatement(GeneratedYangParser.UsesAugmentStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * usesAugmentStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitUsesAugmentStatement(GeneratedYangParser.UsesAugmentStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * augmentStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterAugmentStatement(GeneratedYangParser.AugmentStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * augmentStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitAugmentStatement(GeneratedYangParser.AugmentStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * whenStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterWhenStatement(GeneratedYangParser.WhenStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * whenStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitWhenStatement(GeneratedYangParser.WhenStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * rpcStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterRpcStatement(GeneratedYangParser.RpcStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * rpcStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitRpcStatement(GeneratedYangParser.RpcStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * inputStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterInputStatement(GeneratedYangParser.InputStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * inputStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitInputStatement(GeneratedYangParser.InputStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * outputStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterOutputStatement(GeneratedYangParser.OutputStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * outputStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitOutputStatement(GeneratedYangParser.OutputStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * notificationStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterNotificationStatement(GeneratedYangParser.NotificationStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * notificationStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitNotificationStatement(GeneratedYangParser.NotificationStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * deviationStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDeviationStatement(GeneratedYangParser.DeviationStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * deviationStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDeviationStatement(GeneratedYangParser.DeviationStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateNotSupportedStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDeviateNotSupportedStatement(GeneratedYangParser.DeviateNotSupportedStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateNotSupportedStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDeviateNotSupportedStatement(GeneratedYangParser.DeviateNotSupportedStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateAddStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDeviateAddStatement(GeneratedYangParser.DeviateAddStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateAddStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDeviateAddStatement(GeneratedYangParser.DeviateAddStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateDeleteStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDeviateDeleteStatement(GeneratedYangParser.DeviateDeleteStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateDeleteStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDeviateDeleteStatement(GeneratedYangParser.DeviateDeleteStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateReplaceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterDeviateReplaceStatement(GeneratedYangParser.DeviateReplaceStatementContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * deviateReplaceStatement.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitDeviateReplaceStatement(GeneratedYangParser.DeviateReplaceStatementContext currentContext);
+
+    /**
+     * Enter a parse tree produced by GeneratedYangParser for grammar rule
+     * string.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void enterString(GeneratedYangParser.StringContext currentContext);
+
+    /**
+     * Exit a parse tree produced by GeneratedYangParser for grammar rule
+     * string.
+     *
+     * @param currentContext current context in the parsed tree.
+     */
+    void exitString(GeneratedYangParser.StringContext currentContext);
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/antlrgencode/package-info.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/antlrgencode/package-info.java
new file mode 100644
index 0000000..e7b82a0
--- /dev/null
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/antlrgencode/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2016 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.
+ */
+
+/**
+ * ANTLR interfaces to be implemented by listener.
+ */
+package org.onosproject.yangutils.parser.antlrgencode;
\ No newline at end of file