[ONOS-3882, 3883, 3892]Implement Yang container, list, leaf, leaf-list parsing

Change-Id: I39039c91385fe0d530d037350ef7833c2459514d
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java
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+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java
@@ -0,0 +1,72 @@
+/*
+ * 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.impl.listeners;
+
+import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
+import org.onosproject.yangutils.parser.impl.TreeWalkListener;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ *  type-stmt           = type-keyword sep identifier-ref-arg-str optsep
+ *                        (";" /
+ *                         "{" stmtsep
+ *                            type-body-stmts
+ *                         "}")
+ *
+ * ANTLR grammar rule
+ * typeStatement : TYPE_KEYWORD string (STMTEND | LEFT_CURLY_BRACE typeBodyStatements RIGHT_CURLY_BRACE);
+ */
+
+/**
+ * Implements listener based call back function corresponding to the "type"
+ * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ */
+public final class TypeListener {
+
+    /**
+     * Creates a new type listener.
+     */
+    private TypeListener() {
+    }
+
+    /**
+     * It is called when parser receives an input matching the grammar
+     * rule (type), performs validation and updates the data model
+     * tree.
+     *
+     * @param listener listener's object.
+     * @param ctx context object of the grammar rule.
+     */
+    public static void processTypeEntry(TreeWalkListener listener,
+                                        GeneratedYangParser.TypeStatementContext ctx) {
+        // TODO method implementation
+    }
+
+    /**
+     * It is called when parser exits from grammar rule (type), it performs
+     * validation and updates the data model tree.
+     *
+     * @param listener listener's object.
+     * @param ctx context object of the grammar rule.
+     */
+    public static void processTypeExit(TreeWalkListener listener,
+                                       GeneratedYangParser.TypeStatementContext ctx) {
+        // TODO method implementation
+    }
+}
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