DiffContainer


1   /*******************************************************************************
2    * Copyright (c) 2000, 2006 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.compare.structuremergeviewer;
12  
13  import java.util.ArrayList  ;
14  
15  /**
16   * The standard implementation of a diff container element.
17   * <p>
18   * This class may be instantiated, or further subclassed.
19   * </p>
20   */
21  public abstract class DiffContainer extends DiffElement implements IDiffContainer {
22  
23      private static IDiffElement[] fgEmptyArray= new IDiffElement[0];
24      private ArrayList   fChildren;
25      
26      /**
27       * Creates a new container with the specified kind under the given parent. 
28       *
29       * @param parent under which the new container is added as a child or <code>null</code>.
30       * @param kind of difference (defined in <code>Differencer</code>).
31       */
32      public DiffContainer(IDiffContainer parent, int kind) {
33          super(parent, kind);
34      }
35      
36      /**
37       * Tries to find the child with the given name.
38       * Returns <code>null</code> if no such child exists.
39       * 
40       * @param name of the child to find
41       * @return the first element with a matching name
42       */
43      public IDiffElement findChild(String   name) {
44          Object  [] children= getChildren();
45          for (int i= 0; i < children.length; i++) {
46              IDiffElement child= (IDiffElement) children[i];
47              if (name.equals(child.getName()))
48                  return child;
49          }
50          return null;
51      }
52  
53      /* (non Javadoc)
54       * see IDiffContainer.add
55       */
56      public void add(IDiffElement diff) {
57          if (fChildren == null)
58              fChildren= new ArrayList  ();
59          fChildren.add(diff);
60          diff.setParent(this);
61      }
62  
63      /*
64       * Removes the given child from this container.
65       * If the container becomes empty it is removed from its container.
66       */
67      public void removeToRoot(IDiffElement child) {
68          if (fChildren != null) {
69              fChildren.remove(child);
70              child.setParent(null);
71              if (fChildren.size() == 0) {
72                  IDiffContainer p= getParent();
73                  if (p != null)
74                      p.removeToRoot(this);
75              }
76          }
77      }
78  
79      /**
80       * Removes the given child (non-recursively) from this container.
81       *
82       * @param child to remove
83       */
84      public void remove(IDiffElement child) {
85          if (fChildren != null) {
86              fChildren.remove(child);
87              child.setParent(null);
88          }
89      }
90      
91      /* (non Javadoc)
92       * see IDiffContainer.hasChildren
93       */
94      public boolean hasChildren() {
95          return fChildren != null && fChildren.size() > 0;
96      }
97  
98      /* (non Javadoc)
99       * see IDiffContainer.getChildren
100      */
101     public IDiffElement[] getChildren() {
102         if (fChildren != null)
103             return (IDiffElement[]) fChildren.toArray(fgEmptyArray);
104         return fgEmptyArray;
105     }
106 }
107 
108
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