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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.jetspeed.om.folder.impl;
18  
19  import java.util.AbstractList;
20  import java.util.List;
21  
22  import org.apache.jetspeed.page.impl.DatabasePageManagerUtils;
23  
24  /***
25   * FolderOrderList
26   *
27   * @author <a href="mailto:rwatler@apache.org">Randy Watler</a>
28   * @version $Id$
29   */
30  class FolderOrderList extends AbstractList
31  {
32      private FolderImpl folder;
33  
34      private List removedFolderOrders;
35  
36      FolderOrderList(FolderImpl folder)
37      {
38          super();
39          this.folder = folder;
40      }
41  
42      /***
43       * wrapNameStringForAdd
44       *
45       * Wraps and validates folder order name string
46       * to be added to this list.
47       *
48       * @param name folder order name string to add
49       * @return list element to add
50       */
51      private FolderOrder wrapNameStringForAdd(String name)
52      {
53          // only non-null names supported
54          if (name == null)
55          {
56              throw new NullPointerException("Unable to add null to list.");
57          }
58          // wrap folder order name string
59          FolderOrder folderOrder = new FolderOrder();
60          folderOrder.setName(name);
61          // make sure element is unique
62          if (folder.accessFolderOrders().contains(folderOrder))
63          {
64              throw new IllegalArgumentException("Unable to add duplicate entry to list: " + folderOrder.getName());
65          }
66          // retrieve from removed list to reuse
67          // previously removed element
68          if (removedFolderOrders != null)
69          {
70              int removedIndex = removedFolderOrders.indexOf(folderOrder);
71              if (removedIndex >= 0)
72              {
73                  folderOrder = (FolderOrder)removedFolderOrders.remove(removedIndex);
74              }
75          }
76          return folderOrder;
77      }
78  
79      /***
80       * getRemovedFolderOrders
81       *
82       * @return removed folder orders tracking collection
83       */
84      private List getRemovedFolderOrders()
85      {
86          if (removedFolderOrders == null)
87          {
88              removedFolderOrders = DatabasePageManagerUtils.createList();
89          }
90          return removedFolderOrders;
91      }
92  
93      /* (non-Javadoc)
94       * @see java.util.List#add(int,java.lang.Object)
95       */
96      public void add(int index, Object element)
97      {
98          // implement for modifiable AbstractList:
99          // validate index
100         if ((index < 0) || (index > folder.accessFolderOrders().size()))
101         {
102             throw new IndexOutOfBoundsException("Unable to add to list at index: " + index);
103         }
104         // wrap and verify folder order name string
105         FolderOrder folderOrder = wrapNameStringForAdd((String)element);
106         // add to underlying ordered list
107         folder.accessFolderOrders().add(index, folderOrder);
108         // set sort order in added element
109         if (index > 0)
110         {
111             folderOrder.setSortOrder(((FolderOrder)folder.accessFolderOrders().get(index-1)).getSortOrder() + 1);
112         }
113         else
114         {
115             folderOrder.setSortOrder(0);
116         }
117         // maintain sort order in subsequent elements
118         for (int i = index, limit = folder.accessFolderOrders().size() - 1; (i < limit); i++)
119         {
120             FolderOrder nextFolderOrder = (FolderOrder)folder.accessFolderOrders().get(i + 1);
121             if (nextFolderOrder.getSortOrder() <= folderOrder.getSortOrder())
122             {
123                 // adjust sort order for next element
124                 nextFolderOrder.setSortOrder(folderOrder.getSortOrder() + 1);
125                 folderOrder = nextFolderOrder;
126             }
127             else
128             {
129                 // sort order maintained for remaining list elements
130                 break;
131             }
132         }
133         // clear all cached folder ordering
134         folder.clearDocumentOrderComparator();
135     }
136 
137     /* (non-Javadoc)
138      * @see java.util.List#get(int)
139      */
140     public Object get(int index)
141     {
142         // implement for modifiable AbstractList:
143         // unwrap folder order name string
144         return ((FolderOrder)folder.accessFolderOrders().get(index)).getName();
145     }
146 
147     /* (non-Javadoc)
148      * @see java.util.List#remove(int)
149      */
150     public Object remove(int index)
151     {
152         // implement for modifiable AbstractList
153         FolderOrder removed = (FolderOrder)folder.accessFolderOrders().remove(index);
154         if (removed != null)
155         {
156             // save removed element 
157             getRemovedFolderOrders().add(removed);
158             // clear all cached folder ordering
159             folder.clearDocumentOrderComparator();
160         }
161         return removed;
162     }
163 
164     /* (non-Javadoc)
165      * @see java.util.List#set(int,java.lang.Object)
166      */
167     public Object set(int index, Object element)
168     {
169         // implement for modifiable AbstractList:
170         // wrap and verify folder order name string
171         FolderOrder newFolderOrder = wrapNameStringForAdd((String)element);
172         // set in underlying ordered list
173         FolderOrder folderOrder = (FolderOrder)folder.accessFolderOrders().set(index, newFolderOrder);
174         // set sort order in new element
175         newFolderOrder.setSortOrder(folderOrder.getSortOrder());
176         // save replaced element
177         getRemovedFolderOrders().add(folderOrder);
178         // clear all cached folder ordering
179         folder.clearDocumentOrderComparator();
180         // return unwrapped folder order name string
181         return folderOrder.getName();
182     }
183 
184     /* (non-Javadoc)
185      * @see java.util.List#size()
186      */
187     public int size()
188     {
189         // implement for modifiable AbstractList
190         return folder.accessFolderOrders().size();
191     }
192 }