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 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
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package org.apache.commons.configuration2.tree;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

 A simple data class used by ExpressionEngine to store the results of the prepareAdd() operation. 
 If a new property is to be added to a configuration, the affected Configuration object must know, where in its hierarchy of configuration nodes new elements have to be added. This information is obtained by an ExpressionEngine object that interprets the key of the new property. This expression engine will pack all information necessary for the configuration to perform the add operation in an instance of this class. 

Information managed by this class contains:


the configuration node, to which new elements must be added
the name of the new node
whether the new node is a child node or an attribute node
if a whole branch is to be added at once, the names of all nodes between
the parent node (the target of the add operation) and the new node

Type parameters:
<T> – the type of nodes this class can handle
Since:
1.3/**
 * <p>
 * A simple data class used by {@link ExpressionEngine} to store
 * the results of the {@code prepareAdd()} operation.
 * </p>
 * <p>
 * If a new property is to be added to a configuration, the affected
 * {@code Configuration} object must know, where in its hierarchy of
 * configuration nodes new elements have to be added. This information is
 * obtained by an {@code ExpressionEngine} object that interprets the key
 * of the new property. This expression engine will pack all information
 * necessary for the configuration to perform the add operation in an instance
 * of this class.
 * </p>
 * <p>
 * Information managed by this class contains:
 * </p>
 * <ul>
 * <li>the configuration node, to which new elements must be added</li>
 * <li>the name of the new node</li>
 * <li>whether the new node is a child node or an attribute node</li>
 * <li>if a whole branch is to be added at once, the names of all nodes between
 * the parent node (the target of the add operation) and the new node</li>
 * </ul>
 *
 * @since 1.3
 * @param <T> the type of nodes this class can handle
 */
public class NodeAddData<T>
{
    
Stores the parent node of the add operation. /** Stores the parent node of the add operation. */
    private final T parent;

    
Stores a list with the names of nodes that are on the path between the
parent node and the new node.
/**
     * Stores a list with the names of nodes that are on the path between the
     * parent node and the new node.
     */
    private final List<String> pathNodes;

    
Stores the name of the new node. /** Stores the name of the new node. */
    private final String newNodeName;

    
Stores the attribute flag. /** Stores the attribute flag. */
    private final boolean attribute;

    
Creates a new instance of NodeAddData and initializes it. 
Params:
parentNode – the parent node of the add operation
newName – the name of the new node
isAttr – flag whether the new node is an attribute
intermediateNodes – an optional collection with path nodes/**
     * Creates a new instance of {@code NodeAddData} and initializes it.
     *
     * @param parentNode the parent node of the add operation
     * @param newName the name of the new node
     * @param isAttr flag whether the new node is an attribute
     * @param intermediateNodes an optional collection with path nodes
     */
    public NodeAddData(final T parentNode, final String newName, final boolean isAttr,
            final Collection<String> intermediateNodes)
    {
        parent = parentNode;
        newNodeName = newName;
        attribute = isAttr;
        pathNodes = createPathNodes(intermediateNodes);
    }

    
Returns a flag if the new node to be added is an attribute.
Returns:
true for an attribute node, false for a child
node/**
     * Returns a flag if the new node to be added is an attribute.
     *
     * @return <b>true</b> for an attribute node, <b>false</b> for a child
     * node
     */
    public boolean isAttribute()
    {
        return attribute;
    }

    
Returns the name of the new node.
Returns:
the new node's name/**
     * Returns the name of the new node.
     *
     * @return the new node's name
     */
    public String getNewNodeName()
    {
        return newNodeName;
    }

    
Returns the parent node.
Returns:
the parent node/**
     * Returns the parent node.
     *
     * @return the parent node
     */
    public T getParent()
    {
        return parent;
    }

    
Returns a list with further nodes that must be added. This is needed if a complete branch is to be added at once. For instance, imagine that there exists only a node database. Now the key database.connection.settings.username (assuming the syntax of the default expression engine) is to be added. Then username is the name of the new node, but the nodes connection and settings must be added to the parent node first. In this example these names would be returned by this method. 
Returns:
a list with the names of nodes that must be added as parents of
the new node (never null)/**
     * Returns a list with further nodes that must be added. This is needed if a
     * complete branch is to be added at once. For instance, imagine that there
     * exists only a node {@code database}. Now the key
     * {@code database.connection.settings.username} (assuming the syntax
     * of the default expression engine) is to be added. Then
     * {@code username} is the name of the new node, but the nodes
     * {@code connection} and {@code settings} must be added to
     * the parent node first. In this example these names would be returned by
     * this method.
     *
     * @return a list with the names of nodes that must be added as parents of
     * the new node (never <b>null</b>)
     */
    public List<String> getPathNodes()
    {
        return pathNodes;
    }

    
Creates the list with path nodes. Handles null input.
Params:
intermediateNodes – the nodes passed to the constructor
Returns:
an unmodifiable list of path nodes/**
     * Creates the list with path nodes. Handles null input.
     *
     * @param intermediateNodes the nodes passed to the constructor
     * @return an unmodifiable list of path nodes
     */
    private static List<String> createPathNodes(
            final Collection<String> intermediateNodes)
    {
        if (intermediateNodes == null)
        {
            return Collections.emptyList();
        }
        return Collections.unmodifiableList(new ArrayList<>(
                intermediateNodes));
    }
}