001/* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 * 
007 * Project Info:  http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it 
010 * under the terms of the GNU Lesser General Public License as published by 
011 * the Free Software Foundation; either version 2.1 of the License, or 
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but 
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
022 * USA.  
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
025 * in the United States and other countries.]
026 * 
027 * ---------------------------------
028 * ClassLoaderObjectDescription.java
029 * ---------------------------------
030 * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
031 *
032 * Original Author:  Thomas Morgner;
033 * Contributor(s):   David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: ClassLoaderObjectDescription.java,v 1.5 2005/11/14 11:01:04 mungady Exp $
036 *
037 * Changes (from 19-Feb-2003)
038 * -------------------------
039 * 19-Feb-2003 : Added standard header and Javadocs (DG);
040 * 29-Apr-2003 : Distilled from the JFreeReport project and moved into JCommon
041 *
042 */
043
044package org.jfree.xml.factory.objects;
045
046import java.lang.reflect.Constructor;
047import java.lang.reflect.Modifier;
048
049import org.jfree.util.ObjectUtilities;
050
051/**
052 * An object-description for a class loader.
053 *
054 * @author Thomas Morgner
055 */
056public class ClassLoaderObjectDescription extends AbstractObjectDescription {
057
058    /**
059     * Creates a new object description.
060     */
061    public ClassLoaderObjectDescription() {
062        super(Object.class);
063        setParameterDefinition("class", String.class);
064    }
065
066    /**
067     * Creates an object based on this object description.
068     *
069     * @return The object.
070     */
071    public Object createObject() {
072        try {
073            final String o = (String) getParameter("class");
074            return ObjectUtilities.getClassLoader(getClass()).loadClass(o).newInstance();
075        }
076        catch (Exception e) {
077            return null;
078        }
079    }
080
081    /**
082     * Sets the parameters of the object description to match the supplied object.
083     *
084     * @param o  the object.
085     *
086     * @throws ObjectFactoryException if there is a problem while reading the
087     * properties of the given object.
088     */
089    public void setParameterFromObject(final Object o) throws ObjectFactoryException {
090        if (o == null) {
091            throw new ObjectFactoryException("The Object is null.");
092        }
093        try {
094            final Constructor c = o.getClass().getConstructor(new Class[0]);
095            if (!Modifier.isPublic(c.getModifiers())) {
096                throw new ObjectFactoryException
097                    ("The given object has no public default constructor. [" + o.getClass() + "]");
098            }
099            setParameter("class", o.getClass().getName());
100        }
101        catch (Exception e) {
102            throw new ObjectFactoryException
103                ("The given object has no default constructor. [" + o.getClass() + "]", e);
104        }
105    }
106}