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Java > Open Source Codes > net > mlw > vlh > DefaultValueListHandlerImpl


1 /**
2  * Copyright (c) 2003 held jointly by the individual authors.
3  *
4  * This library is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU Lesser General Public License as published
6  * by the Free Software Foundation; either version 2.1 of the License, or
7  * (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; with out even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public License
15  * along with this library; if not, write to the Free Software Foundation,
16  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
17  *
18  * > http://www.gnu.org/copyleft/lesser.html
19  * > http://www.opensource.org/licenses/lgpl-license.php
20  */
21 package net.mlw.vlh;
22
23 import java.util.Collections JavaDoc;
24 import java.util.Comparator JavaDoc;
25
26 import org.apache.commons.beanutils.PropertyUtils;
27 import org.apache.commons.logging.Log;
28 import org.apache.commons.logging.LogFactory;
29
30 /**
31  * This default implementation of the ValueListHandler service used Jakartas
32  * digester to create a Configuration object.
33  *
34  * @author Matthew L. Wilson, Andrej Zachar
35  * @version $Revision: 1.15 $ $Date: 2006/03/29 19:47:49 $
36  */
37 public class DefaultValueListHandlerImpl implements ValueListHandler
38 {
39    /**
40     * Compares two beans.
41     *
42     * @author Matthew L. Wilson
43     * @version $Revision: 1.15 $ $Date: 2006/03/29 19:47:49 $
44     */
45    public static class BeanComparator implements Comparator JavaDoc
46    {
47       /** The direction to sort. */
48       private int direction = -1;
49
50       /** The method to sort upon. */
51       private String JavaDoc method = null;
52
53       /**
54        * Default constructor.
55        *
56        * @param pmethod
57        * The method to sort upon.
58        * @param pdirection
59        * The direction to sort.
60        */
61       public BeanComparator(String JavaDoc pmethod, int pdirection)
62       {
63          this.method = pmethod;
64          this.direction = pdirection;
65       }
66
67       /**
68        * @see java.util.Comparator.compare(Object, Object)
69        */
70       public int compare(Object JavaDoc obj1, Object JavaDoc obj2)
71       {
72          try
73          {
74             obj1 = PropertyUtils.getProperty(obj1, method);
75             obj2 = PropertyUtils.getProperty(obj2, method);
76
77             if (obj1 == null)
78             {
79                return direction * -1;
80             }
81             else if (obj2 == null)
82             {
83                return direction;
84             }
85             else if (obj1 instanceof Comparable JavaDoc)
86             {
87                return ((Comparable JavaDoc) obj1).compareTo(obj2) * direction;
88             }
89          }
90          catch (Exception JavaDoc e)
91          {
92             // TODO: do not swallow this!
93 e.printStackTrace();
94          }
95
96          return 0;
97       }
98    }
99
100    /** Commons logger. */
101    private static final Log LOGGER = LogFactory.getLog(DefaultValueListHandlerImpl.class);
102
103    /** The configuration for this implementation. * */
104    private Configuration config = new Configuration();
105
106    /**
107     * Creates a new instance of ValueListHandler
108     */
109    public DefaultValueListHandlerImpl()
110    {}
111
112    /**
113     * @param name
114     * of adapter
115     * @return ValueListAdapter
116     */
117    private ValueListAdapter getAdapter(String JavaDoc name)
118    {
119       ValueListAdapter adapter = config.getAdapter(name);
120       if (adapter == null)
121       {
122          throw new NullPointerException JavaDoc("Adapter could not be located: " + name);
123       }
124       return adapter;
125    }
126
127    /**
128     * @return Returns the config.
129     */
130    public Configuration getConfig()
131    {
132       return config;
133    }
134
135    /**
136     * @see com.mlw.vlh.ValueListHander.getValueList(ValueListInfo info, String
137     * name)
138     *
139     */
140    public ValueList getValueList(String JavaDoc name, ValueListInfo info)
141    {
142       if (info == null)
143       {
144          info = new ValueListInfo();
145          if (LOGGER.isDebugEnabled())
146          {
147             LOGGER.debug("Creating a new ValueListInfo for the adapter '" + name + "'.");
148          }
149       }
150       
151       info.getFilters().put(ValueListInfo.VALUE_LIST_NAME, name);
152       
153       ValueListAdapter adapter = getAdapter(name);
154       ValueList valueList = adapter.getValueList(name, info);
155
156       if (LOGGER.isDebugEnabled())
157       {
158          LOGGER.debug("The ValueList was loaded from the adapter '" + name + "'.");
159       }
160
161
162       if ((adapter.getAdapterType() & ValueListAdapter.DO_FOCUS) == ValueListAdapter.DO_FOCUS)
163       {
164          throw new NullPointerException JavaDoc("Not yet implemented!");
165       }
166
167       if ((adapter.getAdapterType() & ValueListAdapter.DO_FILTER) == ValueListAdapter.DO_FILTER)
168       {
169          throw new NullPointerException JavaDoc("Not yet implemented!");
170       }
171       if ((adapter.getAdapterType() & ValueListAdapter.DO_SORT) == ValueListAdapter.DO_SORT)
172       {
173          if (valueList.getValueListInfo() != null && valueList.getValueListInfo().getSortingColumn() != null
174                && valueList.getValueListInfo().getSortingDirection() != null && valueList.getList() != null)
175          {
176             Collections.sort(valueList.getList(), new BeanComparator(valueList.getValueListInfo().getSortingColumn(), valueList
177                   .getValueListInfo().getSortingDirection().intValue()));
178             LOGGER.debug("The ValueList was sorted by post process.");
179          }
180       }
181       if ((adapter.getAdapterType() & ValueListAdapter.DO_PAGE) == ValueListAdapter.DO_PAGE)
182       {
183          if (valueList.getValueListInfo() != null && valueList.getList() != null)
184          {
185             int pagingPage = valueList.getValueListInfo().getPagingPage();
186             int pagingNumberPer = valueList.getValueListInfo().getPagingNumberPer();
187             int totalNumberOfEntries = valueList.getValueListInfo().getTotalNumberOfEntries();
188
189             if (pagingNumberPer < totalNumberOfEntries)
190             {
191                int start = (pagingPage - 1) * pagingNumberPer;
192                if (start >= totalNumberOfEntries)
193                {
194                   start = ((totalNumberOfEntries - 1) / pagingNumberPer) * pagingNumberPer;
195                }
196                int end = Math.min(start + pagingNumberPer, valueList.getList().size());
197                valueList = new DefaultListBackedValueList(valueList.getList().subList(start, end), valueList.getValueListInfo());
198                LOGGER.debug("The ValueList was paged by post process.");
199             }
200          }
201       }
202
203       return valueList;
204    }
205 }
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