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Java > Open Source Codes > org > jfree > xml > factory > objects > ClassLoaderObjectDescription


1 /* ========================================================================
2  * JCommon : a free general purpose class library for the Java(tm) platform
3  * ========================================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jcommon/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ---------------------------------
28  * ClassLoaderObjectDescription.java
29  * ---------------------------------
30  * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
31  *
32  * Original Author: Thomas Morgner;
33  * Contributor(s): David Gilbert (for Object Refinery Limited);
34  *
35  * $Id: ClassLoaderObjectDescription.java,v 1.5 2005/11/14 11:01:04 mungady Exp $
36  *
37  * Changes (from 19-Feb-2003)
38  * -------------------------
39  * 19-Feb-2003 : Added standard header and Javadocs (DG);
40  * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon
41  *
42  */
43
44 package org.jfree.xml.factory.objects;
45
46 import java.lang.reflect.Constructor JavaDoc;
47 import java.lang.reflect.Modifier JavaDoc;
48
49 import org.jfree.util.ObjectUtilities;
50
51 /**
52  * An object-description for a class loader.
53  *
54  * @author Thomas Morgner
55  */
56 public class ClassLoaderObjectDescription extends AbstractObjectDescription {
57
58     /**
59      * Creates a new object description.
60      */
61     public ClassLoaderObjectDescription() {
62         super(Object JavaDoc.class);
63         setParameterDefinition("class", String JavaDoc.class);
64     }
65
66     /**
67      * Creates an object based on this object description.
68      *
69      * @return The object.
70      */
71     public Object JavaDoc createObject() {
72         try {
73             final String JavaDoc o = (String JavaDoc) getParameter("class");
74             return ObjectUtilities.getClassLoader(getClass()).loadClass(o).newInstance();
75         }
76         catch (Exception JavaDoc e) {
77             return null;
78         }
79     }
80
81     /**
82      * Sets the parameters of the object description to match the supplied object.
83      *
84      * @param o the object.
85      *
86      * @throws ObjectFactoryException if there is a problem while reading the
87      * properties of the given object.
88      */
89     public void setParameterFromObject(final Object JavaDoc o) throws ObjectFactoryException {
90         if (o == null) {
91             throw new ObjectFactoryException("The Object is null.");
92         }
93         try {
94             final Constructor JavaDoc c = o.getClass().getConstructor(new Class JavaDoc[0]);
95             if (!Modifier.isPublic(c.getModifiers())) {
96                 throw new ObjectFactoryException
97                     ("The given object has no public default constructor. [" + o.getClass() + "]");
98             }
99             setParameter("class", o.getClass().getName());
100         }
101         catch (Exception JavaDoc e) {
102             throw new ObjectFactoryException
103                 ("The given object has no default constructor. [" + o.getClass() + "]", e);
104         }
105     }
106 }
107
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