[ONOS-3880, 3881] Yang Listener for Module and Sub-Module

Change-Id: Iee75c3e04af9b66ebc38acb3396aa4c54af5a268
diff --git a/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorType.java b/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorType.java
new file mode 100644
index 0000000..13925bc
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorType.java
@@ -0,0 +1,78 @@
+/*
+ * 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.parserutils;
+
+/**
+ * Maintains listener error type.
+ */
+public enum ListenerErrorType {
+    /**
+     * Represents the parent holder in parsable stack for given YANG construct is invalid.
+     */
+    INVALID_HOLDER(),
+
+    /**
+     * Represents the parent holder in parsable stack for given YANG construct is missing.
+     */
+    MISSING_HOLDER(),
+
+    /**
+     * Represents the current holder in parsable stack for given YANG construct is missing.
+     */
+    MISSING_CURRENT_HOLDER(),
+
+    /**
+     * Represents that the child in parsable stack for given YANG construct is invalid.
+     */
+    INVALID_CHILD(),
+
+    /**
+     * Represents that the cardinality for given YANG construct is invalid.
+     */
+    INVALID_CARDINALITY(),
+
+    /**
+     * Represents that some of earlier parsed data is not handled correctly.
+     */
+    UNHANDLED_PARSED_DATA();
+
+    /**
+     * Returns the message corresponding to listener error type.
+     *
+     * @param errorType enum value for type of error.
+     * @return message corresponding to listener error type.
+     */
+    public static String getErrorType(ListenerErrorType errorType) {
+
+        switch (errorType) {
+        case INVALID_HOLDER:
+            return "Invalid holder for";
+        case MISSING_HOLDER:
+            return "Missing holder at";
+        case MISSING_CURRENT_HOLDER:
+            return "Missing";
+        case INVALID_CHILD:
+            return "Invalid child in";
+        case INVALID_CARDINALITY:
+            return "Invalid cardinality in";
+        case UNHANDLED_PARSED_DATA:
+            return "Unhandled parsed data at";
+        default:
+            return "Problem in";
+        }
+    }
+}
\ No newline at end of file