TreeGroup


1   /*
2    * Copyright (c) Rafael Steil
3    * All rights reserved.
4   
5    * Redistribution and use in source and binary forms, 
6    * with or without modification, are permitted provided 
7    * that the following conditions are met:
8   
9    * 1) Redistributions of source code must retain the above 
10   * copyright notice, this list of conditions and the 
11   * following  disclaimer.
12   * 2)  Redistributions in binary form must reproduce the 
13   * above copyright notice, this list of conditions and 
14   * the following disclaimer in the documentation and/or 
15   * other materials provided with the distribution.
16   * 3) Neither the name of "Rafael Steil" nor 
17   * the names of its contributors may be used to endorse 
18   * or promote products derived from this software without 
19   * specific prior written permission.
20   * 
21   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT 
22   * HOLDERS AND CONTRIBUTORS "AS IS" AND ANY 
23   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, 
24   * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
25   * MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
26   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 
27   * THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 
28   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
29   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES 
30   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
31   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, 
32   * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
33   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 
34   * IN CONTRACT, STRICT LIABILITY, OR TORT 
35   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
36   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
37   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
38   * 
39   * This file creation date: Mar 3, 2003 / 11:28:25 AM
40   * The JForum Project
41   * http://www.jforum.net
42   */
43  package net.jforum.util;
44  
45  import java.util.ArrayList  ;
46  import java.util.Iterator  ;
47  import java.util.List  ;
48  
49  import net.jforum.dao.DataAccessDriver;
50  import net.jforum.dao.TreeGroupDAO;
51  
52  /** 
53   * Implements a tree hierarchy of groups.
54   * This class process all group hierarchy, and each group may have unlimited sub groups.
55   * Each group is called <code>node</code> ( <code>net.jforum.model.GroupNode</code> object ), and
56   * each node may have sub-nodes. For example, given a table like the folowing:  
57   * 
58   * <pre>
59   * <code>
60  * +----+----------------+--------+
61   * | id | name          | parent |
62   * +----+---------------+--------+
63   * |  6 | Parent 1      |      0 |
64   * |  7 | Sub 1.1       |      6 |
65   * |  8 | Sub 1.2       |      6 |
66   * |  9 | SubSub 1.2.1  |      8 |
67   * | 10 | SubSub 1.2.2  |      8 |
68   * | 11 | Parent 2      |      0 |
69   * | 12 | Parent 3      |      0 |
70   * | 13 | Sub 3.1       |     12 |
71   * | 14 | SubSub 3.1.1  |     13 |
72   * | 15 | Sub 3.2       |     12 |
73   * | 16 | Parent 4      |      0 |
74   * +----+---------------+--------+
75   * </code>
76   * </pre>
77   * 
78   * results on the folowing hierarchy 
79   * <pre>
80   * <code>
81   * Parent 1
82   * ------
83   *  |
84   *     Sub 1.1
85   *  ----------
86   *  |
87   *  Sub 1.2
88   *  ----------
89   *      |
90   *      SubSub 1.2.1
91   *      ------------
92   *      |
93   *      SubSub 1.2.2
94   * Parent 2
95   * -----
96   * Parent 3
97   * -----
98   *  |
99   *  Sub 3.1
100  *  ---------
101  *      |
102  *      SubSub 3.1.1
103  *      ------------
104  *  |
105  *  Sub 3.2
106  *  ---------
107  * Parent 4
108  * ------
109  * </code>
110  * </pre>
111  *  
112  * As is possible to see, we have 4 parent groups, called <code>Parent 1</code>, <code>Parent 2</code>, 
113  * <code>Parent 3</code> and <code>Parent 4</code>. <code>Parent 1</code> has 2 sub groups: <code>Sub 1.1</code>
114  * and <code>Sub 1.2</code>. <code>Sub 1.2</code> contains 2 subgroups, <code>SubSub 1.2.1</code> and 
115  * <code>SubSub 1.2.2</code>. As every group is a node, ( <code>GroupNode</code> object ), and as each node
116  * may have sub-nodes, the processing would be as:
117  * <p>
118  * <li> When the method <code>size()</code> of the <code>Parent 1</code> object is called,  the number 2 will
119  * be retorned, because <code>Parent 1</code> has 2 sub groups;
120  * <li> when the <code>size()</code> method is called on the object of <code>Sub 1.1</code>, will be returned 0, because
121  * <code>Sub 1.1</code> does not have any sub groups;
122  * <li> On the other hand, then we call the <code>size()</code> method of the object represented by <code>Sub 1.2</code> object,
123  * we wil have a return value of 2, because <code>Sub 1.2</code> has 2 sub groups.
124  * <br>
125  * The same operation is done to all other groups and its sub groups. 
126  * 
127  * @author Rafael Steil
128  * @version $Id: TreeGroup.java,v 1.8 2005/11/30 13:17:10 rafaelsteil Exp $
129  */
130 public class TreeGroup 
131 {
132     /**
133      * Default Constructor
134      */
135     public TreeGroup() { }
136 
137     
138     /**
139      * Process the group hierarchy.
140      * 
141      * @return <code>List</code> containing the complete group hierarchy. Each element
142      * from the list represents a single <code>GroupNode<code> object.   
143      * */
144     public List   getNodes() throws Exception  
145     {
146         List   nodes = new ArrayList  ();
147         
148         TreeGroupDAO tgm = DataAccessDriver.getInstance().newTreeGroupDAO();
149 
150         List   rootGroups = tgm.selectGroups(0);  
151                 
152         for (Iterator   iter = rootGroups.iterator(); iter.hasNext();) {
153             GroupNode n = (GroupNode)iter.next();
154                         
155             this.checkExtraNodes(n);
156             
157             nodes.add(n);
158         }
159         
160         return nodes;
161     }
162     
163     /**
164      * Searchs for subgroups of a determined group
165      * */
166     private void checkExtraNodes(GroupNode n) throws Exception  
167     {
168         TreeGroupDAO tgm = DataAccessDriver.getInstance().newTreeGroupDAO();
169 
170         List   childGroups = tgm.selectGroups(n.getId()); 
171                 
172         for (Iterator   iter = childGroups.iterator(); iter.hasNext();) {
173             GroupNode f = (GroupNode)iter.next();
174             
175             this.checkExtraNodes(f);
176             
177             n.addNode(f);
178         }
179     }
180 }
181
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