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1   package org.codehaus.plexus.metadata.merge.support;
2   
3   /*
4    * The MIT License
5    *
6    * Copyright (c) 2006, The Codehaus
7    *
8    * Permission is hereby granted, free of charge, to any person obtaining a copy of
9    * this software and associated documentation files (the "Software"), to deal in
10   * the Software without restriction, including without limitation the rights to
11   * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
12   * of the Software, and to permit persons to whom the Software is furnished to do
13   * so, subject to the following conditions:
14   *
15   * The above copyright notice and this permission notice shall be included in all
16   * copies or substantial portions of the Software.
17   *
18   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24   * SOFTWARE.
25   */
26  
27  import java.util.Collections;
28  import java.util.List;
29  
30  import org.codehaus.plexus.metadata.merge.MergeException;
31  import org.codehaus.plexus.metadata.merge.MergeStrategy;
32  
33  /**
34   * Collection of available Merge Strategies.<p>
35   * TODO: Revisit and factor {@link Mergeable#merge(Mergeable)} to use a {@link MergeStrategy}.
36   *
37   * @author <a href='mailto:rahul.thakur.xdev@gmail.com'>Rahul Thakur</a>
38   */
39  public class MergeStrategies {
40      /**
41       * {@link MergeStrategy} implementation wherein the elements are merged
42       * down to the deepest available {@link Mergeable} instance in the DOM tree.
43       */
44      public static final MergeStrategy DEEP = new MergeStrategy() {
45          public void apply(Mergeable dElt, Mergeable rElt) throws MergeException {
46              dElt.merge(rElt);
47          }
48      };
49  
50      /**
51       * {@link MergeStrategy} implementation wherein only the element on
52       * which the merge operation is called is 'merged'. The merge does not
53       * traverse the DOM tree any further.
54       */
55      public static final MergeStrategy SHALLOW = new MergeStrategy() {
56          /**
57           * @throws MergeException
58           * @see org.codehaus.plexus.metadata.merge.MergeStrategy#apply(Mergeable,Mergeable)
59           */
60          public void apply(Mergeable dElt, Mergeable rElt) throws MergeException {
61              AbstractMergeableElement dame = (AbstractMergeableElement) dElt;
62              AbstractMergeableElement rame = (AbstractMergeableElement) rElt;
63  
64              // check if the dominant was in conflict with recessive.
65              List elementNames = dame.getElementNamesForConflictResolution(Collections.EMPTY_LIST);
66  
67              if (!dame.isRecessiveElementInConflict(rame, elementNames)) {
68                  // no conflict, simply add recessive to dominant's parent
69                  dame.getElement().addContent(rame.getElement());
70              }
71          }
72      };
73  }