[ONOS-3905, ONOS-3901, ONOS-3900] choice, grouping and augment data model support.

Change-Id: Iaee5175e4e06249f5b56192f4744e9297289194c
diff --git a/src/main/java/org/onosproject/yangutils/datamodel/YangAugment.java b/src/main/java/org/onosproject/yangutils/datamodel/YangAugment.java
new file mode 100644
index 0000000..16735c2
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/datamodel/YangAugment.java
@@ -0,0 +1,339 @@
+/*
+ * 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.parser.ParsableDataType;
+
+/*-
+ * Reference RFC 6020.
+ *
+ * The "augment" statement allows a module or submodule to add to the
+ *  schema tree defined in an external module, or the current module and
+ *  its submodules, and to add to the nodes from a grouping in a "uses"
+ *  statement.  The argument is a string that identifies a node in the
+ *  schema tree.  This node is called the augment's target node.  The
+ *  target node MUST be either a container, list, choice, case, input,
+ *  output, or notification node.  It is augmented with the nodes defined
+ *  in the sub-statements that follow the "augment" statement.
+ *
+ *  The argument string is a schema node identifier.
+ *  If the "augment" statement is on the top level in a module or
+ *  submodule, the absolute form of a schema node identifier
+ *  MUST be used.  If the "augment" statement is a sub-statement to the
+ *  "uses" statement, the descendant form MUST be used.
+ *
+ *  If the target node is a container, list, case, input, output, or
+ *  notification node, the "container", "leaf", "list", "leaf-list",
+ *  "uses", and "choice" statements can be used within the "augment"
+ *  statement.
+ *
+ *  If the target node is a choice node, the "case" statement, or a case
+ *  shorthand statement can be used within the "augment" statement.
+ *
+ *   If the target node is in another module, then nodes added by the
+ *  augmentation MUST NOT be mandatory nodes.
+ *
+ *  The "augment" statement MUST NOT add multiple nodes with the same
+ *  name from the same module to the target node.
+ *  The augment's sub-statements
+ *
+ *                +--------------+---------+-------------+------------------+
+ *                | substatement | section | cardinality |data model mapping|
+ *                +--------------+---------+-------------+------------------+
+ *                | anyxml       | 7.10    | 0..n        |-not supported    |
+ *                | case         | 7.9.2   | 0..n        |-child nodes      |
+ *                | choice       | 7.9     | 0..n        |-child nodes      |
+ *                | container    | 7.5     | 0..n        |-child nodes      |
+ *                | description  | 7.19.3  | 0..1        |-string           |
+ *                | 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       |
+ *                | uses         | 7.12    | 0..n        |-child nodes      |
+ *                | when         | 7.19.5  | 0..1        |-TODO             |
+ *                +--------------+---------+-------------+------------------+
+ */
+/**
+ * Data model node to maintain information defined in YANG augment.
+ */
+public class YangAugment extends YangNode
+        implements YangLeavesHolder, YangCommonInfo, Parsable {
+
+    /**
+     * Augment target node.
+     */
+    private String targetNode;
+
+    /**
+     * description of augment.
+     */
+    private String description;
+
+    /**
+     * List of leaves.
+     */
+    @SuppressWarnings("rawtypes")
+    private List<YangLeaf> listOfLeaf;
+
+    /**
+     * List of leaf-lists.
+     */
+    @SuppressWarnings("rawtypes")
+    private List<YangLeafList> listOfLeafList;
+
+    /**
+     * reference.
+     */
+    private String reference;
+
+    /**
+     * Status of the node.
+     */
+    private YangStatusType status;
+
+    /**
+     * Create a YANG augment node.
+     */
+    public YangAugment() {
+        super(YangNodeType.AUGMENT_NODE);
+    }
+
+    /**
+     * Get the augmented node.
+     *
+     * @return the augmented node.
+     */
+    public String getTargetNode() {
+        return targetNode;
+    }
+
+    /**
+     * Set the augmented node.
+     *
+     * @param targetNode the augmented node.
+     */
+    public void setTargetNode(String targetNode) {
+        this.targetNode = targetNode;
+    }
+
+    /**
+     * Get the description.
+     *
+     * @return the description.
+     */
+    public String getDescription() {
+        return description;
+    }
+
+    /**
+     * Set the description.
+     *
+     * @param description set the description.
+     */
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    /**
+     * Get the list of leaves.
+     *
+     * @return the list of leaves.
+     */
+    @SuppressWarnings("rawtypes")
+    public List<YangLeaf> getListOfLeaf() {
+        return listOfLeaf;
+    }
+
+    /**
+     * Set the list of leaves.
+     *
+     * @param leafsList the list of leaf to set.
+     */
+    @SuppressWarnings("rawtypes")
+    private void setListOfLeaf(List<YangLeaf> leafsList) {
+        listOfLeaf = leafsList;
+    }
+
+    /**
+     * Add a leaf.
+     *
+     * @param leaf the leaf to be added.
+     */
+    @SuppressWarnings("rawtypes")
+    public void addLeaf(YangLeaf<?> leaf) {
+        if (getListOfLeaf() == null) {
+            setListOfLeaf(new LinkedList<YangLeaf>());
+        }
+
+        getListOfLeaf().add(leaf);
+    }
+
+    /**
+     * Get the list of leaf-list.
+     *
+     * @return the list of leaf-list.
+     */
+    @SuppressWarnings("rawtypes")
+    public List<YangLeafList> getListOfLeafList() {
+        return listOfLeafList;
+    }
+
+    /**
+     * Set the list of leaf-list.
+     *
+     * @param listOfLeafList the list of leaf-list to set.
+     */
+    @SuppressWarnings("rawtypes")
+    private void setListOfLeafList(List<YangLeafList> listOfLeafList) {
+        this.listOfLeafList = listOfLeafList;
+    }
+
+    /**
+     * Add a leaf-list.
+     *
+     * @param leafList the leaf-list to be added.
+     */
+    @SuppressWarnings("rawtypes")
+    public void addLeafList(YangLeafList<?> leafList) {
+        if (getListOfLeafList() == null) {
+            setListOfLeafList(new LinkedList<YangLeafList>());
+        }
+
+        getListOfLeafList().add(leafList);
+    }
+
+    /**
+     * Get the textual reference.
+     *
+     * @return the reference.
+     */
+    public String getReference() {
+        return reference;
+    }
+
+    /**
+     * Set the textual reference.
+     *
+     * @param reference the reference to set.
+     */
+    public void setReference(String reference) {
+        this.reference = reference;
+    }
+
+    /**
+     * Get the status.
+     *
+     * @return the status.
+     */
+    public YangStatusType getStatus() {
+        return status;
+    }
+
+    /**
+     * Set the status.
+     *
+     * @param status the status to set.
+     */
+    public void setStatus(YangStatusType status) {
+        this.status = status;
+    }
+
+    /**
+     * Returns the type of the data as belongs-to.
+     *
+     * @return returns AUGMENT_DATA.
+     */
+    public ParsableDataType getParsableDataType() {
+        return ParsableDataType.AUGMENT_DATA;
+    }
+
+    /**
+     * Validate the data on entering the corresponding parse tree node.
+     *
+     * @throws DataModelException a violation of data model rules.
+     */
+    public void validateDataOnEntry() throws DataModelException {
+        // TODO auto-generated method stub, to be implemented by parser
+    }
+
+    /**
+     * Validate the data on exiting the corresponding parse tree node.
+     *
+     * @throws DataModelException a violation of data model rules.
+     */
+    public void validateDataOnExit() throws DataModelException {
+        // TODO auto-generated method stub, to be implemented by parser
+    }
+
+    /* (non-Javadoc)
+     * @see org.onosproject.yangutils.datamodel.YangNode#getName()
+     */
+    @Override
+    public String getName() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    /* (non-Javadoc)
+     * @see org.onosproject.yangutils.datamodel.YangNode#setName(java.lang.String)
+     */
+    @Override
+    public void setName(String name) {
+        // TODO Auto-generated method stub
+
+    }
+
+    /* (non-Javadoc)
+     * @see org.onosproject.yangutils.datamodel.YangNode#getPackage()
+     */
+    @Override
+    public String getPackage() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    /* (non-Javadoc)
+     * @see org.onosproject.yangutils.datamodel.YangNode#setPackage(java.lang.String)
+     */
+    @Override
+    public void setPackage(String pkg) {
+        // TODO Auto-generated method stub
+
+    }
+
+    /* (non-Javadoc)
+     * @see org.onosproject.yangutils.translator.CodeGenerator#generateJavaCodeEntry()
+     */
+    public void generateJavaCodeEntry() {
+        // TODO Auto-generated method stub
+
+    }
+
+    /* (non-Javadoc)
+     * @see org.onosproject.yangutils.translator.CodeGenerator#generateJavaCodeExit()
+     */
+    public void generateJavaCodeExit() {
+        // TODO Auto-generated method stub
+
+    }
+}