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Java > Open Source Codes > org > dbforms > servlets > reports > JRDataSourceIter


1 /*
2  * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/servlets/reports/JRDataSourceIter.java,v 1.7 2004/10/21 10:44:43 hkollmann Exp $
3  * $Revision: 1.7 $
4  * $Date: 2004/10/21 10:44:43 $
5  *
6  * DbForms - a Rapid Application Development Framework
7  * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
8  *
9  * This library is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22  */
23
24 /**
25  * Use an iterator as data source HOWTO 1) create a Collection of X. Where X
26  * is a complex object with 'fields', X can either be a Set or a Bean. The
27  * container must support Iterator(). Object X must be supported by apache
28  * bean utils 2) somewhere in pagecontext (like session) put the Collection
29  * with key "jasper.input" 3) invoke gets field data from multiple sources,
30  * not just DBform fields context : prefix context__xxx . Uses
31  * pageContext.findAttribute(xxx) session : prefix session__xxxx . Uses
32  * pageContext.getSession().findAttribute(xxx) internal : prefix internal_zzz
33  * attribute of iterator object : no prefix For internal, only
34  * internal__rownum is currently defined For content and session, xxxx may be
35  * a 'simple' type or 'complex' type a 'complex' type is an object supporting
36  * javabean access, instead of the usual '.' notation, use '__' instead.
37  */
38 package org.dbforms.servlets.reports;
39
40 import java.util.Iterator JavaDoc;
41 import java.util.Map JavaDoc;
42
43 import net.sf.jasperreports.engine.JRException;
44
45 import org.apache.commons.beanutils.PropertyUtils;
46 import org.apache.commons.logging.Log;
47 import org.apache.commons.logging.LogFactory;
48
49
50
51 public final class JRDataSourceIter extends JRDataSourceAbstract {
52    private static Log logCat = LogFactory.getLog(JRDataSourceIter.class
53                                                   .getName());
54    Object JavaDoc current = null;
55    private Iterator JavaDoc iter;
56    private int rownum = 0;
57
58    /**
59     * DOCUMENT ME!
60     *
61     * @param iter
62     * @param pageContext
63     */
64    public JRDataSourceIter(Map JavaDoc attributes, Iterator JavaDoc iter) {
65       super(attributes);
66       this.iter = iter;
67       rownum = 0;
68    }
69
70    /**
71     * @see net.sf.jasperreports.engine.JRDataSource#next()
72     */
73    public boolean next() throws JRException {
74       if (!iter.hasNext()) {
75          return false;
76       }
77       current = iter.next();
78       rownum++;
79       return true;
80    }
81
82    /**
83     * DOCUMENT ME!
84     *
85     * @param search
86     *
87     * @return
88     */
89    public final Object JavaDoc getFieldValue(String JavaDoc search) {
90       Object JavaDoc obj = null;
91       try {
92          if (current != null) {
93             // complex, current is a container or a bean
94 logCat.debug("calling PropertyUtils.getProperty " + current + " "
95                          + search);
96             obj = PropertyUtils.getProperty(current, search);
97          }
98       } catch (Exception JavaDoc e) {
99          logCat.error("getCurrentValue: " + e);
100       }
101
102       return obj;
103    }
104 }
105
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