beandocumentfactory.java

Java的面向对象数据库系统的源代码

/*
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 *
 * $Id: BeanDocumentFactory.java,v 1.3 2003/11/02 18:04:59 per_nyfelt Exp $
 */

package org.dom4j.bean;

import org.dom4j.Attribute;
import org.dom4j.DocumentFactory;
import org.dom4j.Element;
import org.dom4j.QName;
import org.dom4j.tree.DefaultAttribute;
import org.xml.sax.Attributes;

/** <p><code>BeanDocumentFactory</code> is a factory of DOM4J objects
  * which may be BeanElements which are backed by JavaBeans
  * and their properties. </p>
  *
  * <p>The tree built allows full XPath expressions from anywhere on the
  * tree.</p>
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.3 $
  */
public class BeanDocumentFactory extends DocumentFactory {

    /** The Singleton instance */
    private static BeanDocumentFactory singleton = new BeanDocumentFactory();

    /** <p>Access to the singleton instance of this factory.</p>
      *
      * @return the default singleon instance
      */
    public static DocumentFactory getInstance() {
        return singleton;
    }


    // Factory methods

    public Element createElement(QName qname) {
        Object bean = createBean( qname );
        if ( bean == null ) {
            return new BeanElement(qname);
        }
        else {
            return new BeanElement(qname, bean);
        }
    }

    public Element createElement(QName qname, Attributes attributes) {
        Object bean = createBean( qname, attributes );
        if ( bean == null ) {
            return new BeanElement(qname);
        }
        else {
            return new BeanElement(qname, bean);
        }
    }

    public Attribute createAttribute(Element owner, QName qname, String value) {
        return new DefaultAttribute(qname, value);
    }


    // Implementation methods

    protected Object createBean( QName qname ) {
        return null;
    }

    protected Object createBean( QName qname, Attributes attributes ) {
        String value = attributes.getValue( "class" );
        if ( value != null ) {
            try {
                Class beanClass = Class.forName(
                    value,
                    true,
                    BeanDocumentFactory.class.getClassLoader()
                );
                return beanClass.newInstance();
            }
            catch (Exception e) {
                handleException(e);
            }
        }
        return null;
    }

    protected void handleException(Exception e) {
        // ignore introspection exceptions
        System.out.println( "#### Warning: couldn't create bean: " + e );
    }
}




/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright
 *    statements and notices.  Redistributions must also contain a
 *    copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the
 *    above copyright notice, this list of conditions and the
 *    following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. The name "DOM4J" must not be used to endorse or promote
 *    products derived from this Software without prior written
 *    permission of MetaStuff, Ltd.  For written permission,
 *    please contact [e-mail].
 *
 * 4. Products derived from this Software may not be called "DOM4J"
 *    nor may "DOM4J" appear in their names without prior written
 *    permission of MetaStuff, Ltd. DOM4J is a registered
 *    trademark of MetaStuff, Ltd.
 *
 * 5. Due credit should be given to the DOM4J Project
 *    (http://dom4j.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * $Id: BeanDocumentFactory.java,v 1.3 2003/11/02 18:04:59 per_nyfelt Exp $
 */