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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.devacfr.maven.skins.reflow;
20  
21  import javax.annotation.Nonnull;
22  import javax.annotation.Nullable;
23  
24  import java.util.Collections;
25  import java.util.List;
26  import java.util.stream.Collectors;
27  
28  import com.google.common.collect.Lists;
29  import org.codehaus.plexus.util.xml.Xpp3Dom;
30  
31  import static java.util.Objects.requireNonNull;
32  
33  /**
34   * Utility class to manipulate {@link Xpp3Dom} model.
35   *
36   * @author Christophe Friederich
37   * @since 2.0
38   */
39  public final class Xpp3Utils {
40  
41      private Xpp3Utils() {
42          throw new UnsupportedOperationException();
43      }
44  
45      /**
46       * Retrieves the child node. Tests both default name and with namespace.
47       *
48       * @param parentNode
49       *            the parent node
50       * @param name
51       *            the child name of node to get
52       * @param namespace
53       *            the namespace (can be empty or {@code null}).
54       * @return Returns Returns {@link Xpp3Dom} representing the child of {@code parentNode} if exists, otherwise returns
55       *         {@code null}.
56       */
57      @Nullable public static Xpp3Dom getFirstChild(@Nullable final Xpp3Dom parentNode,
58          @Nonnull final String name,
59          @Nonnull final String namespace) {
60          if (parentNode == null) {
61              return null;
62          }
63          requireNonNull(namespace);
64          final Xpp3Dom child = parentNode.getChild(requireNonNull(name));
65          if (child != null) {
66              return child;
67          }
68  
69          return parentNode.getChild(namespace + name);
70      }
71  
72      /**
73       * Gets the list of all children name for the {@code parentNode}.
74       *
75       * @param parentNode
76       *            the parent node to use (can be {@code null}.
77       * @return Returns a list of {@link String} representing the name of all children, which may be empty but never
78       *         {@code null}.
79       * @since 1.3
80       */
81      @SuppressWarnings("null")
82      @Nonnull
83      public static List<String> getChildren(@Nullable final Xpp3Dom parentNode) {
84          return getChildrenNodes(parentNode, null).stream().map(Xpp3Dom::getName).collect(Collectors.toList());
85      }
86  
87      /**
88       * Gets children list filtered by name of {@code parentNode}.
89       *
90       * @param parentNode
91       *            the parent node to use.
92       * @param name
93       *            the name of element to filter
94       * @return Returns a list of {@link Xpp3Dom} representing all children element filtered by {@code name} of
95       *         {@code parentNode}.
96       */
97      @SuppressWarnings("null")
98      @Nonnull
99      public static List<Xpp3Dom> getChildrenNodes(@Nullable final Xpp3Dom parentNode, final String name) {
100         if (parentNode == null) {
101             return Collections.emptyList();
102         }
103         final Xpp3Dom[] children = parentNode.getChildren();
104         if (children == null) {
105             return Collections.emptyList();
106         }
107         final List<Xpp3Dom> list = Lists.newArrayListWithCapacity(children.length);
108         for (final Xpp3Dom child : children) {
109             if (name != null) {
110                 if (name.equals(child.getName())) {
111                     list.add(child);
112                 }
113             } else {
114                 list.add(child);
115             }
116         }
117 
118         return list;
119     }
120 }