[ONOS-3898/4069] Yang Utils Extension to support RPC/Notification/Choice/Case/Union

Change-Id: I405852caff3464719e8e586fa8e9ae9b6ed043ff

+/*
+ * 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.datamodel;
+
+import java.util.LinkedList;
+import java.util.List;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.utils.YangConstructType;
+
+import static org.onosproject.yangutils.datamodel.utils.DataModelUtils.detectCollidingChildUtil;
+
+/*
+ * Reference RFC 6020.
+ *
+ * The "input" statement, which is optional, is used to define input
+ * parameters to the RPC operation.  It does not take an argument.  The
+ * substatements to "input" define nodes under the RPC's input node.
+ *
+ * If a leaf in the input tree has a "mandatory" statement with the
+ * value "true", the leaf MUST be present in a NETCONF RPC invocation.
+ * Otherwise, the server MUST return a "missing-element" error.
+ *
+ * If a leaf in the input tree has a default value, the NETCONF server
+ * MUST use this value in the same cases as described in Section 7.6.1.
+ * In these cases, the server MUST operationally behave as if the leaf
+ * was present in the NETCONF RPC invocation with the default value as
+ * its value.
+ *
+ * If a "config" statement is present for any node in the input tree,
+ * the "config" statement is ignored.
+ *
+ * If any node has a "when" statement that would evaluate to false, then
+ * this node MUST NOT be present in the input tree.
+ *
+ * The input substatements
+ *
+ *     +--------------+---------+-------------+------------------+
+ *     | substatement | section | cardinality |data model mapping|
+ *     +--------------+---------+-------------+------------------+
+ *     | anyxml       | 7.10    | 0..n        | -not supported   |
+ *     | choice       | 7.9     | 0..n        | -child nodes     |
+ *     | container    | 7.5     | 0..n        | -child nodes     |
+ *     | grouping     | 7.11    | 0..n        | -child nodes     |
+ *     | leaf         | 7.6     | 0..n        | -YangLeaf        |
+ *     | leaf-list    | 7.7     | 0..n        | -YangLeafList    |
+ *     | list         | 7.8     | 0..n        | -child nodes     |
+ *     | typedef      | 7.3     | 0..n        | -child nodes     |
+ *     | uses         | 7.12    | 0..n        | -child nodes     |
+ *     +--------------+---------+-------------+------------------+
+ */
+
+/**
+ * Data model node to maintain information defined in YANG input.
+ */
+public class YangInput extends YangNode implements YangLeavesHolder, Parsable, CollisionDetector {
+
+    /**
+     * Name of the input.
+     */
+    private String name;
+
+    /**
+     * List of leaves contained.
+     */
+    private List<YangLeaf> listOfLeaf;
+
+    /**
+     * List of leaf-lists contained.
+     */
+    private List<YangLeafList> listOfLeafList;
+
+    /**
+     * Create a rpc input node.
+     */
+    public YangInput() {
+        super(YangNodeType.INPUT_NODE);
+        listOfLeaf = new LinkedList<YangLeaf>();
+        listOfLeafList = new LinkedList<YangLeafList>();
+    }
+
+    @Override
+    public void detectCollidingChild(String identifierName, YangConstructType dataType) throws DataModelException {
+        // Detect colliding child.
+        detectCollidingChildUtil(identifierName, dataType, this);
+    }
+
+    @Override
+    public void detectSelfCollision(String identifierName, YangConstructType dataType) throws DataModelException {
+        if (this.getName().equals(identifierName)) {
+            throw new DataModelException("YANG file error: Duplicate input identifier detected, same as input \""
+                    + this.getName() + "\"");
+        }
+    }
+
+    @Override
+    public YangConstructType getYangConstructType() {
+        return YangConstructType.INPUT_DATA;
+    }
+
+    @Override
+    public void validateDataOnEntry() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public void validateDataOnExit() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public List<YangLeaf> getListOfLeaf() {
+        return listOfLeaf;
+    }
+
+    @Override
+    public void addLeaf(YangLeaf leaf) {
+        getListOfLeaf().add(leaf);
+    }
+
+    @Override
+    public List<YangLeafList> getListOfLeafList() {
+        return listOfLeafList;
+    }
+
+    @Override
+    public void addLeafList(YangLeafList leafList) {
+        getListOfLeafList().add(leafList);
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void setName(String name) {
+        this.name = name;
+    }
+}

@@ -75,6 +75,26 @@ public enum YangNodeType {
     CONTAINER_NODE,
 
     /**
+     * Node contains "YANG's notification" information.
+     */
+    NOTIFICATION_NODE,
+
+    /**
+     * Node contains "YANG's input" information.
+     */
+    INPUT_NODE,
+
+    /**
+     * Node contains "YANG's output" information.
+     */
+    OUTPUT_NODE,
+
+    /**
+     * Node contains "YANG's rpc" information.
+     */
+    RPC_NODE,
+
+    /**
      * Node contains "YANG's list" information.
      */
     LIST_NODE

+/*
+ * 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.datamodel;
+
+import java.util.LinkedList;
+import java.util.List;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.utils.YangConstructType;
+
+import static org.onosproject.yangutils.datamodel.utils.DataModelUtils.detectCollidingChildUtil;
+
+/*
+ * Reference RFC 6020.
+ *
+ * YANG allows the definition of notifications suitable for NETCONF.
+ * YANG data definition statements are used to model the content of the
+ * notification.
+ *
+ * The "notification" statement is used to define a NETCONF
+ * notification.  It takes one argument, which is an identifier,
+ * followed by a block of substatements that holds detailed notification
+ * information.  The "notification" statement defines a notification
+ * node in the schema tree.
+ *
+ * If a leaf in the notification tree has a "mandatory" statement with
+ * the value "true", the leaf MUST be present in a NETCONF notification.
+ *
+ * If a leaf in the notification tree has a default value, the NETCONF
+ * client MUST use this value in the same cases as described in
+ * Section 7.6.1.  In these cases, the client MUST operationally behave
+ * as if the leaf was present in the NETCONF notification with the
+ * default value as its value.
+ *
+ * If a "config" statement is present for any node in the notification
+ * tree, the "config" statement is ignored.
+ *
+ * The notification's substatements
+ *
+ *      +--------------+---------+-------------+------------------+
+ *      | substatement | section | cardinality |data model mapping|
+ *      +--------------+---------+-------------+------------------+
+ *      | anyxml       | 7.10    | 0..n        | -not supported   |
+ *      | choice       | 7.9     | 0..n        | -child nodes     |
+ *      | container    | 7.5     | 0..n        | -child nodes     |
+ *      | description  | 7.19.3  | 0..1        | -string          |
+ *      | grouping     | 7.11    | 0..n        | -child nodes     |
+ *      | if-feature   | 7.18.2  | 0..n        | -TODO            |
+ *      | leaf         | 7.6     | 0..n        | -YangLeaf        |
+ *      | leaf-list    | 7.7     | 0..n        | -YangLeafList    |
+ *      | list         | 7.8     | 0..n        | -child nodes     |
+ *      | reference    | 7.19.4  | 0..1        | -string          |
+ *      | status       | 7.19.2  | 0..1        | -YangStatus      |
+ *      | typedef      | 7.3     | 0..n        | -child nodes     |
+ *      | uses         | 7.12    | 0..n        | -child nodes     |
+ *      +--------------+---------+-------------+------------------+
+ */
+
+/**
+ * Data model node to maintain information defined in YANG notification.
+ */
+public class YangNotification extends YangNode implements YangLeavesHolder, YangCommonInfo, Parsable,
+        CollisionDetector  {
+
+    /**
+     * Name of the notification.
+     */
+    private String name;
+
+    /**
+     * Description of notification.
+     */
+    private String description;
+
+    /**
+     * List of leaves contained.
+     */
+    private List<YangLeaf> listOfLeaf;
+
+    /**
+     * List of leaf-lists contained.
+     */
+    private List<YangLeafList> listOfLeafList;
+
+    /**
+     * Reference of the module.
+     */
+    private String reference;
+
+    /**
+     * Status of the node.
+     */
+    private YangStatusType status = YangStatusType.CURRENT;
+
+    /**
+     * Create a notification node.
+     */
+    public YangNotification() {
+        super(YangNodeType.NOTIFICATION_NODE);
+        listOfLeaf = new LinkedList<YangLeaf>();
+        listOfLeafList = new LinkedList<YangLeafList>();
+    }
+
+    @Override
+    public void detectCollidingChild(String identifierName, YangConstructType dataType) throws DataModelException {
+        // Detect colliding child.
+        detectCollidingChildUtil(identifierName, dataType, this);
+    }
+
+    @Override
+    public void detectSelfCollision(String identifierName, YangConstructType dataType) throws DataModelException {
+        if (this.getName().equals(identifierName)) {
+            throw new DataModelException("YANG file error: Duplicate input identifier detected, same as notification \""
+                    + this.getName() + "\"");
+        }
+    }
+
+    @Override
+    public YangConstructType getYangConstructType() {
+        return YangConstructType.NOTIFICATION_DATA;
+    }
+
+    @Override
+    public void validateDataOnEntry() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public void validateDataOnExit() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public String getDescription() {
+        return description;
+    }
+
+    @Override
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    @Override
+    public List<YangLeaf> getListOfLeaf() {
+        return listOfLeaf;
+    }
+
+    @Override
+    public void addLeaf(YangLeaf leaf) {
+        getListOfLeaf().add(leaf);
+    }
+
+    @Override
+    public List<YangLeafList> getListOfLeafList() {
+        return listOfLeafList;
+    }
+
+    @Override
+    public void addLeafList(YangLeafList leafList) {
+        getListOfLeafList().add(leafList);
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String getReference() {
+        return reference;
+    }
+
+    @Override
+    public void setReference(String reference) {
+        this.reference = reference;
+    }
+
+    @Override
+    public YangStatusType getStatus() {
+        return status;
+    }
+
+    @Override
+    public void setStatus(YangStatusType status) {
+        this.status = status;
+    }
+}

+/*
+ * 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.datamodel;
+
+import java.util.LinkedList;
+import java.util.List;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.utils.YangConstructType;
+
+import static org.onosproject.yangutils.datamodel.utils.DataModelUtils.detectCollidingChildUtil;
+
+/*
+ * Reference RFC 6020.
+ *
+ * The "output" statement, which is optional, is used to define output
+ * parameters to the RPC operation.  It does not take an argument.  The
+ * substatements to "output" define nodes under the RPC's output node.
+ *
+ * If a leaf in the output tree has a "mandatory" statement with the
+ * value "true", the leaf MUST be present in a NETCONF RPC reply.
+ *
+ * If a leaf in the output tree has a default value, the NETCONF client
+ * MUST use this value in the same cases as described in Section 7.6.1.
+ * In these cases, the client MUST operationally behave as if the leaf
+ * was present in the NETCONF RPC reply with the default value as its
+ * value.
+ *
+ * If a "config" statement is present for any node in the output tree,
+ * the "config" statement is ignored.
+ *
+ * If any node has a "when" statement that would evaluate to false, then
+ * this node MUST NOT be present in the output tree.
+ *
+ * The output substatements
+ *
+ *    +--------------+---------+-------------+------------------+
+ *    | substatement | section | cardinality |data model mapping|
+ *    +--------------+---------+-------------+------------------+
+ *    | anyxml       | 7.10    | 0..n        | -not supported   |
+ *    | choice       | 7.9     | 0..n        | -child nodes     |
+ *    | container    | 7.5     | 0..n        | -child nodes     |
+ *    | grouping     | 7.11    | 0..n        | -child nodes     |
+ *    | leaf         | 7.6     | 0..n        | -YangLeaf        |
+ *    | leaf-list    | 7.7     | 0..n        | -YangLeafList    |
+ *    | list         | 7.8     | 0..n        | -child nodes     |
+ *    | typedef      | 7.3     | 0..n        | -child nodes     |
+ *    | uses         | 7.12    | 0..n        | -child nodes     |
+ *    +--------------+---------+-------------+------------------+
+ */
+
+/**
+ * Data model node to maintain information defined in YANG output.
+ */
+public class YangOutput extends YangNode implements YangLeavesHolder, Parsable, CollisionDetector {
+
+    /**
+     * Name of the output.
+     */
+    private String name;
+
+    /**
+     * List of leaves contained.
+     */
+    private List<YangLeaf> listOfLeaf;
+
+    /**
+     * List of leaf-lists contained.
+     */
+    private List<YangLeafList> listOfLeafList;
+
+    /**
+     * Create a rpc output node.
+     */
+    public YangOutput() {
+        super(YangNodeType.OUTPUT_NODE);
+        listOfLeaf = new LinkedList<YangLeaf>();
+        listOfLeafList = new LinkedList<YangLeafList>();
+    }
+
+    @Override
+    public void detectCollidingChild(String identifierName, YangConstructType dataType) throws DataModelException {
+        // Detect colliding child.
+        detectCollidingChildUtil(identifierName, dataType, this);
+    }
+
+    @Override
+    public void detectSelfCollision(String identifierName, YangConstructType dataType) throws DataModelException {
+        if (this.getName().equals(identifierName)) {
+            throw new DataModelException("YANG file error: Duplicate identifier detected, same as output \""
+                    + this.getName() + "\"");
+        }
+    }
+
+    @Override
+    public YangConstructType getYangConstructType() {
+        return YangConstructType.OUTPUT_DATA;
+    }
+
+    @Override
+    public void validateDataOnEntry() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public void validateDataOnExit() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public List<YangLeaf> getListOfLeaf() {
+        return listOfLeaf;
+    }
+
+    @Override
+    public void addLeaf(YangLeaf leaf) {
+        getListOfLeaf().add(leaf);
+    }
+
+    @Override
+    public List<YangLeafList> getListOfLeafList() {
+        return listOfLeafList;
+    }
+
+    @Override
+    public void addLeafList(YangLeafList leafList) {
+        getListOfLeafList().add(leafList);
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void setName(String name) {
+        this.name = name;
+    }
+}

+/*
+ * 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.datamodel;
+
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.utils.YangConstructType;
+
+import static org.onosproject.yangutils.datamodel.utils.DataModelUtils.detectCollidingChildUtil;
+
+/*
+ * Reference RFC 6020.
+ *
+ * The "rpc" statement is used to define a NETCONF RPC operation.  It
+ * takes one argument, which is an identifier, followed by a block of
+ * substatements that holds detailed rpc information.  This argument is
+ * the name of the RPC, and is used as the element name directly under
+ * the <rpc> element, as designated by the substitution group
+ * "rpcOperation" in [RFC4741].
+ *
+ * The "rpc" statement defines an rpc node in the schema tree.  Under
+ * the rpc node, a schema node with the name "input", and a schema node
+ * with the name "output" are also defined.  The nodes "input" and
+ * "output" are defined in the module's namespace.
+ *
+ * The rpc substatements
+ *
+ *    +--------------+---------+-------------+------------------+
+ *    | substatement | section | cardinality |data model mapping|
+ *    +--------------+---------+-------------+------------------+
+ *    | description  | 7.19.3  | 0..1        | -string          |
+ *    | grouping     | 7.11    | 0..n        | -child nodes     |
+ *    | if-feature   | 7.18.2  | 0..n        | -TODO            |
+ *    | input        | 7.13.2  | 0..1        | -child nodes     |
+ *    | output       | 7.13.3  | 0..1        | -child nodes     |
+ *    | reference    | 7.19.4  | 0..1        | -string          |
+ *    | status       | 7.19.2  | 0..1        | -YangStatus      |
+ *    | typedef      | 7.3     | 0..n        | -child nodes     |
+ *    +--------------+---------+-------------+------------------+
+ */
+
+/**
+ * Data model node to maintain information defined in YANG rpc.
+ */
+public class YangRpc extends YangNode implements YangCommonInfo, Parsable,
+        CollisionDetector  {
+
+    /**
+     * Name of the rpc.
+     */
+    private String name;
+
+    /**
+     * Description of rpc.
+     */
+    private String description;
+
+    /**
+     * Reference of the module.
+     */
+    private String reference;
+
+    /**
+     * Status of the node.
+     */
+    private YangStatusType status = YangStatusType.CURRENT;
+
+    /**
+     * Create a rpc node.
+     */
+    public YangRpc() {
+        super(YangNodeType.RPC_NODE);
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public void detectCollidingChild(String identifierName, YangConstructType dataType) throws DataModelException {
+        // Detect colliding child.
+        detectCollidingChildUtil(identifierName, dataType, this);
+    }
+
+    @Override
+    public void detectSelfCollision(String identifierName, YangConstructType dataType) throws DataModelException {
+        if (this.getName().equals(identifierName)) {
+            throw new DataModelException("YANG file error: Duplicate input identifier detected, same as rpc \""
+                    + this.getName() + "\"");
+        }
+    }
+
+    @Override
+    public YangConstructType getYangConstructType() {
+        return YangConstructType.RPC_DATA;
+    }
+
+    @Override
+    public void validateDataOnEntry() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public void validateDataOnExit() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public String getDescription() {
+        return description;
+    }
+
+    @Override
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    @Override
+    public String getReference() {
+        return reference;
+    }
+
+    @Override
+    public void setReference(String reference) {
+        this.reference = reference;
+    }
+
+    @Override
+    public YangStatusType getStatus() {
+        return status;
+    }
+
+    @Override
+    public void setStatus(YangStatusType status) {
+        this.status = status;
+    }
+}

+/*
+ * 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.datamodel;
+
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.utils.YangConstructType;
+
+import java.util.List;
+
+/*
+ * Reference RFC 6020.
+ *
+ * The union built-in type represents a value that corresponds to one of
+ * its member types.
+ *
+ * When the type is "union", the "type" statement (Section 7.4) MUST be
+ * present.  It is used to repeatedly specify each member type of the
+ * union.  It takes as an argument a string that is the name of a member
+ * type.
+ *
+ * A member type can be of any built-in or derived type, except it MUST
+ * NOT be one of the built-in types "empty" or "leafref".
+ *
+ * When a string representing a union data type is validated, the string
+ * is validated against each member type, in the order they are
+ * specified in the "type" statement, until a match is found.
+ *
+ * Any default value or "units" property defined in the member types is
+ * not inherited by the union type.
+ */
+
+/**
+ * Data model node to maintain information defined in YANG union.
+ */
+public class YangUnion implements Parsable {
+
+    // List of YANG type.
+    private List<YangType<?>> typeList;
+
+    // Name of the union.
+    private String unionName;
+
+    /**
+     * Create a YANG union node.
+     */
+    public YangUnion() {
+    }
+
+    /**
+     * Returns list of YANG type.
+     *
+     * @return the list of YANG type
+     */
+    public List<YangType<?>> getTypeList() {
+        return typeList;
+    }
+
+    /**
+     * Returns union name.
+     *
+     * @return the union name
+     */
+    public String getUnionName() {
+        return unionName;
+    }
+
+    /**
+     * Set the list of YANG type.
+     *
+     * @param typeList list of YANG type.
+     */
+    public void setTypeList(List<YangType<?>> typeList) {
+        this.typeList = typeList;
+    }
+
+    /**
+     * Set the union name.
+     *
+     * @param unionName name of the union.
+     */
+    public void setUnionName(String unionName) {
+        this.unionName = unionName;
+    }
+
+    @Override
+    public YangConstructType getYangConstructType() {
+        return YangConstructType.UNION_DATA;
+    }
+
+    @Override
+    public void validateDataOnEntry() throws DataModelException {
+        //TODO: implement the method.
+    }
+
+    @Override
+    public void validateDataOnExit() throws DataModelException {
+        //TODO: implement the method.
+    }
+}

@@ -29,6 +29,8 @@ import org.onosproject.yangutils.parser.impl.listeners.BaseFileListener;
 import org.onosproject.yangutils.parser.impl.listeners.BelongsToListener;
 import org.onosproject.yangutils.parser.impl.listeners.BitListener;
 import org.onosproject.yangutils.parser.impl.listeners.BitsListener;
+import org.onosproject.yangutils.parser.impl.listeners.CaseListener;
+import org.onosproject.yangutils.parser.impl.listeners.ChoiceListener;
 import org.onosproject.yangutils.parser.impl.listeners.ConfigListener;
 import org.onosproject.yangutils.parser.impl.listeners.ContactListener;
 import org.onosproject.yangutils.parser.impl.listeners.ContainerListener;
@@ -54,6 +56,7 @@ import org.onosproject.yangutils.parser.impl.listeners.PresenceListener;
 import org.onosproject.yangutils.parser.impl.listeners.ReferenceListener;
 import org.onosproject.yangutils.parser.impl.listeners.RevisionDateListener;
 import org.onosproject.yangutils.parser.impl.listeners.RevisionListener;
+import org.onosproject.yangutils.parser.impl.listeners.ShortCaseListener;
 import org.onosproject.yangutils.parser.impl.listeners.StatusListener;
 import org.onosproject.yangutils.parser.impl.listeners.SubModuleListener;
 import org.onosproject.yangutils.parser.impl.listeners.TypeDefListener;
@@ -914,32 +917,32 @@ public class TreeWalkListener implements GeneratedYangListener {
 
     @Override
     public void enterChoiceStatement(GeneratedYangParser.ChoiceStatementContext ctx) {
-        // TODO: implement the method.
+        ChoiceListener.processChoiceEntry(this, ctx);
     }
 
     @Override
     public void exitChoiceStatement(GeneratedYangParser.ChoiceStatementContext ctx) {
-        // TODO: implement the method.
+        ChoiceListener.processChoiceExit(this, ctx);
     }
 
     @Override
     public void enterShortCaseStatement(GeneratedYangParser.ShortCaseStatementContext ctx) {
-        // TODO: implement the method.
+        ShortCaseListener.processShortCaseEntry(this, ctx);
     }
 
     @Override
     public void exitShortCaseStatement(GeneratedYangParser.ShortCaseStatementContext ctx) {
-        // TODO: implement the method.
+        ShortCaseListener.processShortCaseExit(this, ctx);
     }
 
     @Override
     public void enterCaseStatement(GeneratedYangParser.CaseStatementContext ctx) {
-        // TODO: implement the method.
+        CaseListener.processCaseEntry(this, ctx);
     }
 
     @Override
     public void exitCaseStatement(GeneratedYangParser.CaseStatementContext ctx) {
-        // TODO: implement the method.
+        CaseListener.processCaseExit(this, ctx);
     }
 
     @Override

+/*
+ * Copyright 2014-2016 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.datamodel.YangCase;
+import org.onosproject.yangutils.datamodel.YangChoice;
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.TreeWalkListener;
+
+import static org.onosproject.yangutils.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
+import static org.onosproject.yangutils.datamodel.utils.YangDataModelFactory.getYangCaseNode;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerCollisionDetector.detectCollidingChildUtil;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.EXIT;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructExtendedListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_CURRENT_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.UNHANDLED_PARSED_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.getValidIdentifier;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.validateCardinalityMaxOne;
+import static org.onosproject.yangutils.utils.YangConstructType.CASE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.DESCRIPTION_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.REFERENCE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.STATUS_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.WHEN_DATA;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ *  case-stmt           = case-keyword sep identifier-arg-str optsep
+ *                        (";" /
+ *                         "{" stmtsep
+ *                             ;; these stmts can appear in any order
+ *                             [when-stmt stmtsep]
+ *                             *(if-feature-stmt stmtsep)
+ *                             [status-stmt stmtsep]
+ *                             [description-stmt stmtsep]
+ *                             [reference-stmt stmtsep]
+ *                             *(data-def-stmt stmtsep)
+ *                         "}")
+ *
+ * ANTLR grammar rule
+ * caseStatement : CASE_KEYWORD identifier (STMTEND | LEFT_CURLY_BRACE (whenStatement | ifFeatureStatement
+ *               | statusStatement | descriptionStatement | referenceStatement | dataDefStatement)* RIGHT_CURLY_BRACE);
+ */
+
+/**
+ * Implements listener based call back function corresponding to the "case" rule
+ * defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ */
+public final class CaseListener {
+
+    /**
+     * Create a new case listener.
+     */
+    private CaseListener() {
+    }
+
+    /**
+     * It is called when parser enters grammar rule (case), it perform
+     * validations and updates the data model tree.
+     *
+     * @param listener listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processCaseEntry(TreeWalkListener listener,
+            GeneratedYangParser.CaseStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, CASE_DATA, ctx.identifier().getText(), ENTRY);
+
+        // Check validity of identifier and remove double quotes.
+        String identifier = getValidIdentifier(ctx.identifier().getText(), CASE_DATA, ctx);
+
+        // Validate sub statement cardinality.
+        validateSubStatementsCardinality(ctx);
+
+        Parsable curData = listener.getParsedDataStack().peek();
+
+        // Check for identifier collision
+        int line = ctx.getStart().getLine();
+        int charPositionInLine = ctx.getStart().getCharPositionInLine();
+        detectCollidingChildUtil(listener, line, charPositionInLine, identifier, CASE_DATA);
+
+        if (curData instanceof YangChoice) {
+            YangCase caseNode = getYangCaseNode(JAVA_GENERATION);
+            caseNode.setName(identifier);
+            YangNode curNode = (YangNode) curData;
+            try {
+                curNode.addChild(caseNode);
+            } catch (DataModelException e) {
+                throw new ParserException(constructExtendedListenerErrorMessage(UNHANDLED_PARSED_DATA,
+                        CASE_DATA, ctx.identifier().getText(), ENTRY, e.getMessage()));
+            }
+            listener.getParsedDataStack().push(caseNode);
+        } else {
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, CASE_DATA,
+                    ctx.identifier().getText(), ENTRY));
+        }
+    }
+
+    /**
+     * It is called when parser exits from grammar rule (case), it perform
+     * validations and update the data model tree.
+     *
+     * @param listener Listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processCaseExit(TreeWalkListener listener,
+            GeneratedYangParser.CaseStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, CASE_DATA, ctx.identifier().getText(), EXIT);
+
+        if (listener.getParsedDataStack().peek() instanceof YangCase) {
+            listener.getParsedDataStack().pop();
+        } else {
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, CASE_DATA,
+                    ctx.identifier().getText(), EXIT));
+        }
+    }
+
+    /**
+     * Validates the cardinality of case sub-statements as per grammar.
+     *
+     * @param ctx context object of the grammar rule
+     */
+    private static void validateSubStatementsCardinality(GeneratedYangParser.CaseStatementContext ctx) {
+
+        validateCardinalityMaxOne(ctx.whenStatement(), WHEN_DATA, CASE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.statusStatement(), STATUS_DATA, CASE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.descriptionStatement(), DESCRIPTION_DATA, CASE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.referenceStatement(), REFERENCE_DATA, CASE_DATA, ctx.identifier().getText());
+    }
+}

+/*
+ * Copyright 2014-2016 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.datamodel.YangAugment;
+import org.onosproject.yangutils.datamodel.YangCase;
+import org.onosproject.yangutils.datamodel.YangChoice;
+import org.onosproject.yangutils.datamodel.YangContainer;
+import org.onosproject.yangutils.datamodel.YangGrouping;
+import org.onosproject.yangutils.datamodel.YangInput;
+import org.onosproject.yangutils.datamodel.YangList;
+import org.onosproject.yangutils.datamodel.YangModule;
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.datamodel.YangNotification;
+import org.onosproject.yangutils.datamodel.YangOutput;
+import org.onosproject.yangutils.datamodel.YangSubModule;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.Parsable;
+import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.TreeWalkListener;
+
+import static org.onosproject.yangutils.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
+import static org.onosproject.yangutils.datamodel.utils.YangDataModelFactory.getYangChoiceNode;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerCollisionDetector.detectCollidingChildUtil;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.EXIT;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructExtendedListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_CURRENT_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.UNHANDLED_PARSED_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.getValidIdentifier;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.validateCardinalityMaxOne;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.validateMutuallyExclusiveChilds;
+import static org.onosproject.yangutils.utils.YangConstructType.CASE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.CHOICE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.CONFIG_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.DEFAULT_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.DESCRIPTION_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.MANDATORY_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.REFERENCE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.SHORT_CASE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.STATUS_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.WHEN_DATA;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ *  choice-stmt         = choice-keyword sep identifier-arg-str optsep
+ *                        (";" /
+ *                         "{" stmtsep
+ *                             ;; these stmts can appear in any order
+ *                             [when-stmt stmtsep]
+ *                             *(if-feature-stmt stmtsep)
+ *                             [default-stmt stmtsep]
+ *                             [config-stmt stmtsep]
+ *                             [mandatory-stmt stmtsep]
+ *                             [status-stmt stmtsep]
+ *                             [description-stmt stmtsep]
+ *                             [reference-stmt stmtsep]
+ *                             *((short-case-stmt / case-stmt) stmtsep)
+ *                         "}")
+ *
+ * ANTLR grammar rule
+ * choiceStatement : CHOICE_KEYWORD identifier (STMTEND | LEFT_CURLY_BRACE (whenStatement | ifFeatureStatement
+ *                 | defaultStatement | configStatement | mandatoryStatement | statusStatement | descriptionStatement
+ *                 | referenceStatement | shortCaseStatement | caseStatement)* RIGHT_CURLY_BRACE);
+ */
+
+/**
+ * Implements listener based call back function corresponding to the "choice"
+ * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ */
+public final class ChoiceListener {
+
+    /**
+     * Create a new choice listener.
+     */
+    private ChoiceListener() {
+    }
+
+    /**
+     * It is called when parser receives an input matching the grammar rule
+     * (choice), perform validations and update the data model tree.
+     *
+     * @param listener Listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processChoiceEntry(TreeWalkListener listener,
+            GeneratedYangParser.ChoiceStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, CHOICE_DATA, ctx.identifier().getText(), ENTRY);
+
+        // Check validity of identifier and remove double quotes.
+        String identifier = getValidIdentifier(ctx.identifier().getText(), CHOICE_DATA, ctx);
+
+        // Validate sub statement cardinality.
+        validateSubStatementsCardinality(ctx);
+
+        Parsable curData = listener.getParsedDataStack().peek();
+
+        // Check for identifier collision
+        int line = ctx.getStart().getLine();
+        int charPositionInLine = ctx.getStart().getCharPositionInLine();
+        detectCollidingChildUtil(listener, line, charPositionInLine, identifier, CHOICE_DATA);
+
+        if (curData instanceof YangModule || curData instanceof YangSubModule || curData instanceof YangContainer
+                || curData instanceof YangList || curData instanceof YangCase || curData instanceof YangGrouping
+                || curData instanceof YangAugment  || curData instanceof YangInput || curData instanceof YangOutput
+                || curData instanceof YangNotification) {
+
+            YangChoice choiceNode = getYangChoiceNode(JAVA_GENERATION);
+            choiceNode.setName(identifier);
+
+            YangNode curNode = (YangNode) curData;
+            try {
+                curNode.addChild(choiceNode);
+            } catch (DataModelException e) {
+                throw new ParserException(constructExtendedListenerErrorMessage(UNHANDLED_PARSED_DATA,
+                        CHOICE_DATA, ctx.identifier().getText(), ENTRY, e.getMessage()));
+            }
+            listener.getParsedDataStack().push(choiceNode);
+        } else {
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER,
+                    CHOICE_DATA, ctx.identifier().getText(), ENTRY));
+        }
+    }
+
+    /**
+     * It is called when parser exits from grammar rule (choice), it perform
+     * validations and update the data model tree.
+     *
+     * @param listener Listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processChoiceExit(TreeWalkListener listener,
+            GeneratedYangParser.ChoiceStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, CHOICE_DATA, ctx.identifier().getText(), EXIT);
+
+        if (listener.getParsedDataStack().peek() instanceof YangChoice) {
+            listener.getParsedDataStack().pop();
+        } else {
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, CHOICE_DATA,
+                    ctx.identifier().getText(), EXIT));
+        }
+    }
+
+    /**
+     * Validates the cardinality of choice sub-statements as per grammar.
+     *
+     * @param ctx context object of the grammar rule.
+     */
+    private static void validateSubStatementsCardinality(GeneratedYangParser.ChoiceStatementContext ctx) {
+
+        validateCardinalityMaxOne(ctx.whenStatement(), WHEN_DATA, CHOICE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.defaultStatement(), DEFAULT_DATA, CHOICE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.configStatement(), CONFIG_DATA, CHOICE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.mandatoryStatement(), MANDATORY_DATA, CHOICE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.statusStatement(), STATUS_DATA, CHOICE_DATA, ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.descriptionStatement(), DESCRIPTION_DATA, CHOICE_DATA,
+                ctx.identifier().getText());
+        validateCardinalityMaxOne(ctx.referenceStatement(), REFERENCE_DATA, CHOICE_DATA, ctx.identifier().getText());
+        validateMutuallyExclusiveChilds(ctx.shortCaseStatement(), SHORT_CASE_DATA, ctx.caseStatement(), CASE_DATA,
+                CHOICE_DATA, ctx.identifier().getText());
+    }
+}

+/*
+ * 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.antlr.v4.runtime.ParserRuleContext;
+import org.antlr.v4.runtime.tree.ParseTree;
+import org.onosproject.yangutils.datamodel.YangCase;
+import org.onosproject.yangutils.datamodel.YangChoice;
+import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
+import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.TreeWalkListener;
+
+import static org.onosproject.yangutils.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
+import static org.onosproject.yangutils.datamodel.utils.YangDataModelFactory.getYangCaseNode;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerCollisionDetector.detectCollidingChildUtil;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.EXIT;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructExtendedListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_CHILD;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_CURRENT_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.UNHANDLED_PARSED_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerUtil.getValidIdentifier;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
+import static org.onosproject.yangutils.utils.YangConstructType.CASE_DATA;
+import static org.onosproject.yangutils.utils.YangConstructType.SHORT_CASE_DATA;
+
+/*
+ * Reference: RFC6020 and YANG ANTLR Grammar
+ *
+ * ABNF grammar as per RFC6020
+ * short-case-stmt     = container-stmt /
+ *                       leaf-stmt /
+ *                       leaf-list-stmt /
+ *                       list-stmt /
+ *                       anyxml-stmt
+ *
+ * ANTLR grammar rule
+ * shortCaseStatement : containerStatement | leafStatement | leafListStatement | listStatement;
+ */
+
+/**
+ * Implements listener based call back function corresponding to the "short
+ * case" rule defined in ANTLR grammar file for corresponding ABNF rule in RFC
+ * 6020.
+ */
+public final class ShortCaseListener {
+
+    /**
+     * Create a new short case listener.
+     */
+    private ShortCaseListener() {
+    }
+
+    /**
+     * It is called when parser enters grammar rule (short case), it perform
+     * validations and updates the data model tree.
+     *
+     * @param listener listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processShortCaseEntry(TreeWalkListener listener,
+            GeneratedYangParser.ShortCaseStatementContext ctx) {
+
+        ParseTree errorConstructContext;
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, SHORT_CASE_DATA, "", ENTRY);
+
+        YangCase caseNode = getYangCaseNode(JAVA_GENERATION);
+
+        if (ctx.containerStatement() != null) {
+            caseNode.setName(getValidIdentifier(ctx.containerStatement().identifier().getText(), CASE_DATA, ctx));
+            errorConstructContext = ctx.containerStatement();
+        } else if (ctx.listStatement() != null) {
+            caseNode.setName(getValidIdentifier(ctx.listStatement().identifier().getText(), CASE_DATA, ctx));
+            errorConstructContext = ctx.listStatement();
+        } else if (ctx.leafListStatement() != null) {
+            caseNode.setName(getValidIdentifier(ctx.leafListStatement().identifier().getText(), CASE_DATA, ctx));
+            errorConstructContext = ctx.leafListStatement();
+        } else if (ctx.leafStatement() != null) {
+            caseNode.setName(getValidIdentifier(ctx.leafStatement().identifier().getText(), CASE_DATA, ctx));
+            errorConstructContext = ctx.leafStatement();
+        } else {
+            throw new ParserException(constructListenerErrorMessage(INVALID_CHILD, SHORT_CASE_DATA, "", ENTRY));
+        }
+        // TODO implement for augment.
+
+        int line = ((ParserRuleContext) errorConstructContext).getStart().getLine();
+        int charPositionInLine = ((ParserRuleContext) errorConstructContext).getStart().getCharPositionInLine();
+
+        // Check for identifier collision
+        detectCollidingChildUtil(listener, line, charPositionInLine, caseNode.getName(), CASE_DATA);
+
+        if ((listener.getParsedDataStack().peek()) instanceof YangChoice) {
+            try {
+                ((YangChoice) listener.getParsedDataStack().peek()).addChild(caseNode);
+            } catch (DataModelException e) {
+                throw new ParserException(constructExtendedListenerErrorMessage(UNHANDLED_PARSED_DATA,
+                        SHORT_CASE_DATA, caseNode.getName(), ENTRY, e.getMessage()));
+            }
+            listener.getParsedDataStack().push(caseNode);
+        } else {
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, SHORT_CASE_DATA,
+                    caseNode.getName(), ENTRY));
+        }
+    }
+
+    /**
+     * It is called when parser exits from grammar rule (short case), it perform
+     * validations and update the data model tree.
+     *
+     * @param listener Listener's object
+     * @param ctx context object of the grammar rule
+     */
+    public static void processShortCaseExit(TreeWalkListener listener,
+            GeneratedYangParser.ShortCaseStatementContext ctx) {
+
+        // Check for stack to be non empty.
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, SHORT_CASE_DATA, "", EXIT);
+
+        if (listener.getParsedDataStack().peek() instanceof YangCase) {
+            listener.getParsedDataStack().pop();
+        } else {
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, SHORT_CASE_DATA,
+                    "", EXIT));
+        }
+    }
+}

+/*
+ * 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.translator.tojava.javamodel;
+
+import java.io.IOException;
+import org.onosproject.yangutils.datamodel.YangInput;
+import org.onosproject.yangutils.translator.tojava.HasJavaFileInfo;
+import org.onosproject.yangutils.translator.tojava.HasJavaImportData;
+import org.onosproject.yangutils.translator.tojava.HasTempJavaCodeFragmentFiles;
+import org.onosproject.yangutils.translator.tojava.JavaCodeGenerator;
+import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
+import org.onosproject.yangutils.translator.tojava.JavaImportData;
+import org.onosproject.yangutils.translator.tojava.TempJavaCodeFragmentFiles;
+
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_INTERFACE_WITH_BUILDER;
+import static org.onosproject.yangutils.translator.tojava.utils.GenerateJavaCodeExitBuilder.generateJavaFile;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCaptialCase;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCurNodePackage;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getPackageDirPathFromJavaJPackage;
+import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.createPackage;
+import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.getAbsolutePackagePath;
+
+/**
+ * Input information extended to support java code generation.
+ */
+public class YangJavaInput extends YangInput
+        implements JavaCodeGenerator, HasJavaFileInfo,
+        HasJavaImportData, HasTempJavaCodeFragmentFiles {
+
+    /**
+     * Contains information of the java file being generated.
+     */
+    private JavaFileInfo javaFileInfo;
+
+    /**
+     * Contains information of the imports to be inserted in the java file
+     * generated.
+     */
+    private JavaImportData javaImportData;
+
+    /**
+     * File handle to maintain temporary java code fragments as per the code
+     * snippet types.
+     */
+    private TempJavaCodeFragmentFiles tempFileHandle;
+
+    /**
+     * Creates an instance of java input.
+     */
+    public YangJavaInput() {
+        super();
+        setJavaFileInfo(new JavaFileInfo());
+        setJavaImportData(new JavaImportData());
+        getJavaFileInfo().setGeneratedFileTypes(GENERATE_INTERFACE_WITH_BUILDER);
+    }
+
+    /**
+     * Returns the generated java file information.
+     *
+     * @return generated java file information
+     */
+    @Override
+    public JavaFileInfo getJavaFileInfo() {
+
+        if (javaFileInfo == null) {
+            throw new RuntimeException("Missing java info in java datamodel node");
+        }
+        return javaFileInfo;
+    }
+
+    /**
+     * Set the java file info object.
+     *
+     * @param javaInfo java file info object
+     */
+    @Override
+    public void setJavaFileInfo(JavaFileInfo javaInfo) {
+
+        javaFileInfo = javaInfo;
+    }
+
+    /**
+     * Returns the data of java imports to be included in generated file.
+     *
+     * @return data of java imports to be included in generated file
+     */
+    @Override
+    public JavaImportData getJavaImportData() {
+
+        return javaImportData;
+    }
+
+    /**
+     * Set the data of java imports to be included in generated file.
+     *
+     * @param javaImportData data of java imports to be included in generated
+     *            file
+     */
+    @Override
+    public void setJavaImportData(JavaImportData javaImportData) {
+
+        this.javaImportData = javaImportData;
+    }
+
+    /**
+     * Returns the temporary file handle.
+     *
+     * @return temporary file handle
+     */
+    @Override
+    public TempJavaCodeFragmentFiles getTempJavaCodeFragmentFiles() {
+
+        if (tempFileHandle == null) {
+            throw new RuntimeException("Missing temporary file handle for" +
+                    "current node " + getJavaFileInfo().getJavaName());
+        }
+        return tempFileHandle;
+    }
+
+    /**
+     * Set temporary file handle.
+     *
+     * @param fileHandle temporary file handle
+     */
+    @Override
+    public void setTempJavaCodeFragmentFiles(TempJavaCodeFragmentFiles fileHandle) {
+
+        tempFileHandle = fileHandle;
+    }
+
+    /**
+     * Prepare the information for java code generation corresponding to YANG
+     * container info.
+     *
+     * @param codeGenDir code generation directory
+     * @throws IOException IO operation fail
+     */
+    @Override
+    public void generateCodeEntry(String codeGenDir) throws IOException {
+
+        getJavaFileInfo().setJavaName(getCaptialCase(getCamelCase(getName())));
+        getJavaFileInfo().setPackage(getCurNodePackage(this));
+        getJavaFileInfo().setPackageFilePath(
+                getPackageDirPathFromJavaJPackage(getJavaFileInfo().getPackage()));
+        getJavaFileInfo().setBaseCodeGenPath(codeGenDir);
+
+        String absloutePath = getAbsolutePackagePath(
+                getJavaFileInfo().getBaseCodeGenPath(),
+                getJavaFileInfo().getPackageFilePath());
+        createPackage(absloutePath, getName());
+        setTempJavaCodeFragmentFiles(new TempJavaCodeFragmentFiles(
+                getJavaFileInfo().getGeneratedFileTypes(), absloutePath,
+                getJavaFileInfo().getJavaName()));
+
+        getTempJavaCodeFragmentFiles().addCurNodeLeavesInfoToTempFiles(this);
+
+        getTempJavaCodeFragmentFiles().addCurNodeInfoInParentTempFile(this, false);
+    }
+
+    /**
+     * Create a java file using the YANG grouping info.
+     *
+     * @throws IOException IO operation fail
+     */
+    @Override
+    public void generateCodeExit() throws IOException {
+
+        generateJavaFile(GENERATE_INTERFACE_WITH_BUILDER, this);
+        getTempJavaCodeFragmentFiles().close();
+    }
+}

+/*
+ * 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.translator.tojava.javamodel;
+
+import java.io.IOException;
+import org.onosproject.yangutils.datamodel.YangOutput;
+import org.onosproject.yangutils.translator.tojava.HasJavaFileInfo;
+import org.onosproject.yangutils.translator.tojava.HasJavaImportData;
+import org.onosproject.yangutils.translator.tojava.HasTempJavaCodeFragmentFiles;
+import org.onosproject.yangutils.translator.tojava.JavaCodeGenerator;
+import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
+import org.onosproject.yangutils.translator.tojava.JavaImportData;
+import org.onosproject.yangutils.translator.tojava.TempJavaCodeFragmentFiles;
+
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_INTERFACE_WITH_BUILDER;
+import static org.onosproject.yangutils.translator.tojava.utils.GenerateJavaCodeExitBuilder.generateJavaFile;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCaptialCase;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCurNodePackage;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getPackageDirPathFromJavaJPackage;
+import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.createPackage;
+import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.getAbsolutePackagePath;
+
+/**
+ * Output information extended to support java code generation.
+ */
+public class YangJavaOutput extends YangOutput
+        implements JavaCodeGenerator, HasJavaFileInfo,
+        HasJavaImportData, HasTempJavaCodeFragmentFiles {
+
+    /**
+     * Contains information of the java file being generated.
+     */
+    private JavaFileInfo javaFileInfo;
+
+    /**
+     * Contains information of the imports to be inserted in the java file
+     * generated.
+     */
+    private JavaImportData javaImportData;
+
+    /**
+     * File handle to maintain temporary java code fragments as per the code
+     * snippet types.
+     */
+    private TempJavaCodeFragmentFiles tempFileHandle;
+
+    /**
+     * Creates an instance of java output.
+     */
+    public YangJavaOutput() {
+        super();
+        setJavaFileInfo(new JavaFileInfo());
+        setJavaImportData(new JavaImportData());
+        getJavaFileInfo().setGeneratedFileTypes(GENERATE_INTERFACE_WITH_BUILDER);
+    }
+
+    /**
+     * Returns the generated java file information.
+     *
+     * @return generated java file information
+     */
+    @Override
+    public JavaFileInfo getJavaFileInfo() {
+
+        if (javaFileInfo == null) {
+            throw new RuntimeException("Missing java info in java datamodel node");
+        }
+        return javaFileInfo;
+    }
+
+    /**
+     * Set the java file info object.
+     *
+     * @param javaInfo java file info object
+     */
+    @Override
+    public void setJavaFileInfo(JavaFileInfo javaInfo) {
+
+        javaFileInfo = javaInfo;
+    }
+
+    /**
+     * Returns the data of java imports to be included in generated file.
+     *
+     * @return data of java imports to be included in generated file
+     */
+    @Override
+    public JavaImportData getJavaImportData() {
+
+        return javaImportData;
+    }
+
+    /**
+     * Set the data of java imports to be included in generated file.
+     *
+     * @param javaImportData data of java imports to be included in generated
+     *            file
+     */
+    @Override
+    public void setJavaImportData(JavaImportData javaImportData) {
+
+        this.javaImportData = javaImportData;
+    }
+
+    /**
+     * Returns the temporary file handle.
+     *
+     * @return temporary file handle
+     */
+    @Override
+    public TempJavaCodeFragmentFiles getTempJavaCodeFragmentFiles() {
+
+        if (tempFileHandle == null) {
+            throw new RuntimeException("Missing temporary file handle for" +
+                    "current node " + getJavaFileInfo().getJavaName());
+        }
+        return tempFileHandle;
+    }
+
+    /**
+     * Set temporary file handle.
+     *
+     * @param fileHandle temporary file handle
+     */
+    @Override
+    public void setTempJavaCodeFragmentFiles(TempJavaCodeFragmentFiles fileHandle) {
+
+        tempFileHandle = fileHandle;
+    }
+
+    /**
+     * Prepare the information for java code generation corresponding to YANG
+     * container info.
+     *
+     * @param codeGenDir code generation directory
+     * @throws IOException IO operation fail
+     */
+    @Override
+    public void generateCodeEntry(String codeGenDir) throws IOException {
+
+        getJavaFileInfo().setJavaName(getCaptialCase(getCamelCase(getName())));
+        getJavaFileInfo().setPackage(getCurNodePackage(this));
+        getJavaFileInfo().setPackageFilePath(
+                getPackageDirPathFromJavaJPackage(getJavaFileInfo().getPackage()));
+        getJavaFileInfo().setBaseCodeGenPath(codeGenDir);
+
+        String absloutePath = getAbsolutePackagePath(
+                getJavaFileInfo().getBaseCodeGenPath(),
+                getJavaFileInfo().getPackageFilePath());
+        createPackage(absloutePath, getName());
+        setTempJavaCodeFragmentFiles(new TempJavaCodeFragmentFiles(
+                getJavaFileInfo().getGeneratedFileTypes(), absloutePath,
+                getJavaFileInfo().getJavaName()));
+
+        getTempJavaCodeFragmentFiles().addCurNodeLeavesInfoToTempFiles(this);
+
+        getTempJavaCodeFragmentFiles().addCurNodeInfoInParentTempFile(this, false);
+    }
+
+    /**
+     * Create a java file using the YANG grouping info.
+     *
+     * @throws IOException IO operation fail
+     */
+    @Override
+    public void generateCodeExit() throws IOException {
+
+        generateJavaFile(GENERATE_INTERFACE_WITH_BUILDER, this);
+        getTempJavaCodeFragmentFiles().close();
+    }
+}

@@ -235,6 +235,41 @@ public enum YangConstructType {
     DATA_DEF_DATA,
 
     /**
+     * Identifies the YANG union element parsed data.
+     */
+    UNION_DATA,
+
+    /**
+     * Identifies the YANG notification element parsed data.
+     */
+    NOTIFICATION_DATA,
+
+    /**
+     * Identifies the YANG when element parsed data.
+     */
+    WHEN_DATA,
+
+    /**
+     * Identifies the YANG input element parsed data.
+     */
+    INPUT_DATA,
+
+    /**
+     * Identifies the YANG output element parsed data.
+     */
+    OUTPUT_DATA,
+
+    /**
+     * Identifies the YANG rpc element parsed data.
+     */
+    RPC_DATA,
+
+    /**
+     * Identifies the YANG short case element parsed data.
+     */
+    SHORT_CASE_DATA,
+
+    /**
      * Identifies the derived data type.
      */
     DERIVED;
@@ -334,8 +369,22 @@ public enum YangConstructType {
                 return "default";
             case DATA_DEF_DATA:
                 return "data-def-substatements";
+            case WHEN_DATA:
+                return "when";
+            case INPUT_DATA:
+                return "input";
+            case OUTPUT_DATA:
+                return "ouput";
+            case RPC_DATA:
+                return "rpc";
+            case SHORT_CASE_DATA:
+                return "short-case";
             case DERIVED:
                 return "derived";
+            case NOTIFICATION_DATA:
+                return "notification";
+            case UNION_DATA:
+                return "union";
             default:
                 return "yang";
         }

+/*
+ * Copyright 2014-2016 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 static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.core.Is.is;
+import org.junit.Test;
+import org.onosproject.yangutils.datamodel.YangCase;
+import org.onosproject.yangutils.datamodel.YangChoice;
+import org.onosproject.yangutils.datamodel.YangContainer;
+import org.onosproject.yangutils.datamodel.YangLeaf;
+import org.onosproject.yangutils.datamodel.YangModule;
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.datamodel.YangNodeType;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.YangUtilsParserManager;
+
+import java.io.IOException;
+import java.util.ListIterator;
+
+/**
+ * Test cases for case listener.
+ */
+public class CaseListenerTest {
+
+    private final YangUtilsParserManager manager = new YangUtilsParserManager();
+
+    /**
+     * Checks multiple case statement.
+     */
+    @Test
+    public void processCaseStatement() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/CaseStatement.yang");
+
+        // Check whether the data model tree returned is of type module.
+        assertThat((node instanceof YangModule), is(true));
+
+        // Check whether the node type is set properly to module.
+        assertThat(node.getNodeType(), is(YangNodeType.MODULE_NODE));
+
+        // Check whether the module name is set correctly.
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangContainer yangContainer = (YangContainer) yangNode.getChild();
+        assertThat(yangContainer.getName(), is("food"));
+
+        YangChoice yangChoice = (YangChoice) yangContainer.getChild();
+        assertThat(yangChoice.getName(), is("snack"));
+
+        YangCase yangCase1 = (YangCase) yangChoice.getChild();
+        assertThat(yangCase1.getName(), is("sports-arena"));
+
+        // Check whether leaf properties as set correctly.
+        ListIterator<YangLeaf> leafIterator1 = yangCase1.getListOfLeaf().listIterator();
+        YangLeaf leafInfo1 = leafIterator1.next();
+
+        assertThat(leafInfo1.getLeafName(), is("pretzel"));
+
+        YangCase yangCase2 = (YangCase) yangCase1.getNextSibling();
+        assertThat(yangCase2.getName(), is("late-night"));
+
+        // Check whether leaf properties as set correctly.
+        ListIterator<YangLeaf> leafIterator2 = yangCase2.getListOfLeaf().listIterator();
+        YangLeaf leafInfo2 = leafIterator2.next();
+
+        assertThat(leafInfo2.getLeafName(), is("chocolate"));
+    }
+
+    /**
+     * Checks duplicate case in choice.
+     */
+    @Test(expected = ParserException.class)
+    public void processDuplicateCaseInChoice() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/DuplicateCaseInChoice.yang");
+    }
+
+    /**
+     * Checks duplicate leaf at different hierarchy.
+     */
+    @Test(expected = ParserException.class)
+    public void processDuplicateLeafInHierarchy() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/DuplicateLeafInHierarchy.yang");
+    }
+
+    /**
+     * Checks duplicate leaf in different case within choice.
+     */
+    @Test(expected = ParserException.class)
+    public void processDuplicateLeafInChoice() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/DuplicateLeafInChoice.yang");
+    }
+
+    /**
+     * Checks same case within different choice.
+     */
+    @Test
+    public void processCaseStatementSameEntryDifferentChoice() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/CaseStatementSameEntryDifferentChoice.yang");
+
+        // Check whether the data model tree returned is of type module.
+        assertThat((node instanceof YangModule), is(true));
+
+        // Check whether the node type is set properly to module.
+        assertThat(node.getNodeType(), is(YangNodeType.MODULE_NODE));
+
+        // Check whether the module name is set correctly.
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangContainer yangContainer = (YangContainer) yangNode.getChild();
+        assertThat(yangContainer.getName(), is("food"));
+
+        YangChoice yangChoice = (YangChoice) yangContainer.getChild();
+        assertThat(yangChoice.getName(), is("snack"));
+
+        YangCase yangCase1 = (YangCase) yangChoice.getChild();
+        assertThat(yangCase1.getName(), is("sports-arena"));
+
+        // Check whether leaf properties as set correctly.
+        ListIterator<YangLeaf> leafIterator1 = yangCase1.getListOfLeaf().listIterator();
+        YangLeaf leafInfo1 = leafIterator1.next();
+
+        assertThat(leafInfo1.getLeafName(), is("pretzel"));
+
+        YangChoice yangChoice2 = (YangChoice) yangChoice.getNextSibling();
+        assertThat(yangChoice2.getName(), is("lunch"));
+
+        YangCase yangCase2 = (YangCase) yangChoice2.getChild();
+        assertThat(yangCase2.getName(), is("sports-arena"));
+
+        // Check whether leaf properties as set correctly.
+        ListIterator<YangLeaf> leafIterator2 = yangCase2.getListOfLeaf().listIterator();
+        YangLeaf leafInfo2 = leafIterator2.next();
+
+        assertThat(leafInfo2.getLeafName(), is("chocolate"));
+    }
+
+    /**
+     * Checks case choice hierarchy.
+     */
+    @Test
+    public void processCaseChoiceHierarchy() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/CaseChoiceHierarchy.yang");
+
+        // Check whether the data model tree returned is of type module.
+        assertThat((node instanceof YangModule), is(true));
+
+        // Check whether the node type is set properly to module.
+        assertThat(node.getNodeType(), is(YangNodeType.MODULE_NODE));
+
+        // Check whether the module name is set correctly.
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangContainer yangContainer = (YangContainer) yangNode.getChild();
+        assertThat(yangContainer.getName(), is("food"));
+
+        YangChoice yangChoice1 = (YangChoice) yangContainer.getChild();
+        assertThat(yangChoice1.getName(), is("snack"));
+
+        YangCase yangCase1 = (YangCase) yangChoice1.getChild();
+        assertThat(yangCase1.getName(), is("sports-arena"));
+
+        // Check whether leaf properties as set correctly.
+        ListIterator<YangLeaf> leafIterator1 = yangCase1.getListOfLeaf().listIterator();
+        YangLeaf leafInfo1 = leafIterator1.next();
+
+        assertThat(leafInfo1.getLeafName(), is("pretzel"));
+
+        YangCase yangCase2 = (YangCase) yangCase1.getNextSibling();
+        assertThat(yangCase2.getName(), is("late-night"));
+
+        YangChoice yangChoice2 = (YangChoice) yangCase2.getChild();
+        assertThat(yangChoice2.getName(), is("dinner"));
+
+        YangCase yangCase3 = (YangCase) yangChoice2.getChild();
+        assertThat(yangCase3.getName(), is("late-night"));
+
+        // Check whether leaf properties as set correctly.
+        ListIterator<YangLeaf> leafIterator2 = yangCase3.getListOfLeaf().listIterator();
+        YangLeaf leafInfo2 = leafIterator2.next();
+        assertThat(leafInfo2.getLeafName(), is("beer"));
+    }
+}

+/*
+ * Copyright 2014-2016 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 static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.core.Is.is;
+import org.junit.Test;
+import org.onosproject.yangutils.datamodel.YangChoice;
+import org.onosproject.yangutils.datamodel.YangContainer;
+import org.onosproject.yangutils.datamodel.YangModule;
+import org.onosproject.yangutils.datamodel.YangNode;
+import org.onosproject.yangutils.datamodel.YangNodeType;
+import org.onosproject.yangutils.parser.exceptions.ParserException;
+import org.onosproject.yangutils.parser.impl.YangUtilsParserManager;
+
+import java.io.IOException;
+
+/**
+ * Test cases for choice listener.
+ */
+public class ChoiceListenerTest {
+
+    private final YangUtilsParserManager manager = new YangUtilsParserManager();
+
+    /**
+     * Checks choice statement without body.
+     */
+    @Test
+    public void processChoiceStatementWithoutBody() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ChoiceStatementWithoutBody.yang");
+
+        // Check whether the data model tree returned is of type module.
+        assertThat((node instanceof YangModule), is(true));
+
+        // Check whether the node type is set properly to module.
+        assertThat(node.getNodeType(), is(YangNodeType.MODULE_NODE));
+
+        // Check whether the module name is set correctly.
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangContainer yangContainer = (YangContainer) yangNode.getChild();
+        assertThat(yangContainer.getName(), is("food"));
+
+        YangChoice yangChoice = (YangChoice) yangContainer.getChild();
+        assertThat(yangChoice.getName(), is("snack"));
+    }
+
+    /**
+     * Checks choice statement with stmt end.
+     */
+    @Test
+    public void processChoiceStatementWithStmtend() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ChoiceStatementWithStmtend.yang");
+
+        // Check whether the data model tree returned is of type module.
+        assertThat((node instanceof YangModule), is(true));
+
+        // Check whether the node type is set properly to module.
+        assertThat(node.getNodeType(), is(YangNodeType.MODULE_NODE));
+
+        // Check whether the module name is set correctly.
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangContainer yangContainer = (YangContainer) yangNode.getChild();
+        assertThat(yangContainer.getName(), is("food"));
+
+        YangChoice yangChoice = (YangChoice) yangContainer.getChild();
+        assertThat(yangChoice.getName(), is("snack"));
+    }
+
+    /**
+     * Checks choice statement duplicate entry.
+     */
+    @Test(expected = ParserException.class)
+    public void processChoiceStatementDuplicateEntry() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ChoiceStatementDuplicateEntry.yang");
+    }
+
+    /**
+     * Checks choice statement with same entry in two different container.
+     */
+    @Test
+    public void processChoiceStatementSameEntryDifferentContainer() throws IOException, ParserException {
+
+        YangNode node = manager.getDataModel("src/test/resources/ChoiceStatementSameEntryDifferentContainer.yang");
+
+        // Check whether the data model tree returned is of type module.
+        assertThat((node instanceof YangModule), is(true));
+
+        // Check whether the node type is set properly to module.
+        assertThat(node.getNodeType(), is(YangNodeType.MODULE_NODE));
+
+        // Check whether the module name is set correctly.
+        YangModule yangNode = (YangModule) node;
+        assertThat(yangNode.getName(), is("Test"));
+
+        YangContainer yangContainer1 = (YangContainer) yangNode.getChild();
+        assertThat(yangContainer1.getName(), is("food1"));
+
+        YangChoice yangChoice1 = (YangChoice) yangContainer1.getChild();
+        assertThat(yangChoice1.getName(), is("snack"));
+
+        YangContainer yangContainer2 = (YangContainer) yangNode.getChild().getNextSibling();
+        assertThat(yangContainer2.getName(), is("food2"));
+
+        YangChoice yangChoice2 = (YangChoice) yangContainer2.getChild();
+        assertThat(yangChoice2.getName(), is("snack"));
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           case sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+           }
+           case late-night {
+               choice dinner {
+                  case late-night {
+                   leaf beer {
+                       type empty;
+                   }
+               }
+           }
+       }
+    }
+  }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           case sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+               leaf beer {
+                   type empty;
+               }
+           }
+           case late-night {
+               leaf chocolate {
+                   type enumeration {
+                       enum dark;
+                       enum milk;
+                       enum first-available;
+                   }
+               }
+           }
+       }
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           case sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+               leaf beer {
+                   type empty;
+               }
+           }
+       }
+       choice lunch {
+           case sports-arena {
+               leaf chocolate {
+                   type enumeration {
+                       enum dark;
+                       enum milk;
+                       enum first-available;
+                   }
+               }
+           }
+       }
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack;
+       choice lunch;
+       choice snack;
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food1 {
+       choice snack;
+       choice lunch;
+    }
+     container food2 {
+       choice snack;
+       choice lunch;
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack;
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+       }
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           case sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+               leaf beer {
+                   type empty;
+               }
+           }
+           case sports-arena {
+               leaf chocolate {
+                   type enumeration {
+                       enum dark;
+                       enum milk;
+                       enum first-available;
+                   }
+               }
+           }
+       }
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           case sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+               leaf beer {
+                   type empty;
+               }
+           }
+           case late-night {
+               leaf pretzel {
+                   type empty;
+               }
+           }
+    }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           case sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+           }
+           case late-night {
+               choice lunch {
+                  case late {
+                   leaf pretzel {
+                       type empty;
+                   }
+               }
+           }
+       }
+    }
+  }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           container sports-arena {
+               leaf pretzel {
+                   type empty;
+               }
+           }
+       }
+    }
+  }
+}

+module Test {
+    yang-version 1;
+    namespace http://huawei.com;
+    prefix Ant;
+     container food {
+       choice snack {
+           list sports-arena {
+               key "pretzel";
+               leaf pretzel {
+                   type int32;
+               }
+           }
+       }
+    }
+  }
+}