litexmlmetadataimpl.java

适合初学者使用的cms和jxta方面的代码

/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 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 end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``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 THE APACHE SOFTWARE FOUNDATION 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.
 *
 *====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: LiteXMLMetadataImpl.java,v 1.3 2006/03/15 20:33:22 bondolo Exp $
 *
 */

package net.jxta.share.metadata;

import net.jxta.document.*;
import org.apache.log4j.*;
import java.util.*;

/**
 *@version $Revision: 1.3 $
 *@author $Author: bondolo $
 */
public class LiteXMLMetadataImpl extends LiteXMLMetadata {

    private final static transient Logger LOG
	= Logger.getLogger(LiteXMLMetadataImpl.class.getName());


    protected Element metadata;

    /**Return the ContentMetadataConstructor used to create instances of this
     * class
     */
    public static ContentMetadataConstructor getConstructor() {
	return new ContentMetadataConstructor() {
		public ContentMetadata newInstance(Element metadataEl)
		    throws IllegalArgumentException {
		    if(metadataEl == null)
			throw new IllegalArgumentException();
		    return new LiteXMLMetadataImpl(metadataEl);
		}
	    };
    }

    public LiteXMLMetadataImpl(Element metadata)
	throws IllegalArgumentException {
	this.metadata = metadata;
	init(metadata);
    }

	/**A safe copy constructor*/
	public LiteXMLMetadataImpl(LiteXMLMetadataImpl lxmlm) {
		location = lxmlm.location;
		metadata = StructuredDocumentFactory.newStructuredDocument(new MimeMediaType("text/xml"), EN_METADATA);
		Element[] melems = getMetadataElements();
		for(int a = 0; a < melems.length; a++)
			metadata.appendChild(melems[a]);
	}

    public Element[] getMetadataElements() {
	Vector results = new Vector();
	Enumeration children = metadata.getChildren();
	Element currentEl;
	while(children.hasMoreElements()) {
	    currentEl = (Element)children.nextElement();
	    //make sure the scheme element isn't returned
	    if(!currentEl.getKey().toString().equals(EN_SCHEME))
		results.addElement(currentEl);
	}
	if(results.size() != 0)
	    return (Element[])results.toArray();
	return new Element[0];
    }
    
/**A function for generating safe copies of this ContentMetadata object.
 *
 * @return a safe copy of this ContentMetadata object
 */
    public Object clone() throws CloneNotSupportedException {
    	return new LiteXMLMetadataImpl(this);
    }
    
    public Element[] getMetadataElements(StructuredDocument root) {
	Vector results = new Vector();
	Enumeration children = metadata.getChildren();
	Element current;
	while(children.hasMoreElements()) {
	    current = (Element)children.nextElement();
	    if(current.getKey().toString().equals(EN_SCHEME))
		continue;
	    results.addElement(duplicateElement(root, current));
	}
	if(results.size() == 0)
	    return new Element[0];
	return (Element[])results.toArray();
    }

    public void appendDocument(StructuredDocument adv, Element el) {
	el.appendChild(duplicateElement(adv, metadata));
    }


    /**Recursively duplicate an element so that it has a different
     * StructuredDocument as a parent.
     *@param doc - the StructuredDocument that will be the parent of the new
     * Element
     *@param srcEl - the Element to duplicate
     *@return a copy of srcEl with doc as its parent
     */
    private static Element duplicateElement(StructuredDocument doc
					    ,Element srcEl) {
	Element newEl = doc.createElement(srcEl.getKey(), srcEl.getValue());
	Enumeration children = srcEl.getChildren();
	while(children.hasMoreElements())
	    newEl.appendChild(duplicateElement(doc, (Element)children.nextElement()));
	return newEl;
    }
}