resourcebase.java

java 开发的一个电子邮局,挺实用的

/**
 * @(#)ResourceBase.java  1.0 2001/09/02
 *
 * Copyleft 2000 by Steve Excellent Lee
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package org.bulbul.webmail.xmlresource;

import java.io.IOException;
import java.util.*;

import org.apache.xerces.framework.*;
import org.apache.xerces.parsers.*;

import org.w3c.dom.*;
import org.xml.sax.*;

import net.wastl.webmail.server.WebMailServer;

/**
 * A ResourceBundle implementation that uses a XML file to store the resources.
 * Modified from Sebastian Schaffert's 
 * net.wastl.webmail.xml.XMLResourceBundle.java
 *
 * New scheme:
 * We separate locale resource to differenet files instead of putting all 
 * different locale resources into single xml file, since the encoding 
 * can't vary. (A single xml file can only use one encoding).
 *
 * Subclasses must override <code>getXmlResourceFilename</code> and 
 * provide the filename which contains appropriate locale-specific resources.
 *
 * Note:
 * The resource files must resides in the directory that defined by 
 * `webmail.template.path' property, hence <code>getXmlResourceFilename</code>
 * must returns only filename without pathname)
 *
 * @author	  Steve Excellent Lee
 * @version	 1.0 2001
 */
public abstract class ResourceBase extends ResourceBundle {
	protected boolean debug = true;

	protected Document xmlRoot = null;

	protected Element elementBundle = null;	// The <BUNDLE> element of resource xml file
	protected Element elem_common = null;

	/**
	 * Sole constructor.  (For invocation by subclass constructors, typically
	 * implicit.)
	 */
  	public ResourceBase() {
	}
	

	public Enumeration getKeys() {
		Hashtable prop=new Hashtable();
	
		if(elem_common != null) {
			getKeys(elem_common,prop);
		}
		if(elementBundle != null) {
			getKeys(elementBundle,prop);
		}
		return prop.keys();
	}
	
	protected Object handleGetObject(String key) throws MissingResourceException {
		String retval=null;

		// Lazily load the XML resource file
		if (xmlRoot == null) {
			loadXmlResourceFile();
		}
		
		if (elementBundle != null) {
			retval = getResult(elementBundle, key);
		}
		if ((retval == null) && (elem_common != null)) {
			retval = getResult(elem_common,key);
		}

		if (debug)
			System.err.println("XMLResourceBundle: "+key+" = "+retval);

		return retval;
	}

	/**
	 * See class description.
	 */
	abstract protected String getXmlResourceFilename();
	
	protected void loadXmlResourceFile() {
		try {
			DOMParser parser=new DOMParser();
			System.err.println("file://" + 
							WebMailServer.getServer().getProperty("webmail.template.path") + 
							System.getProperty("file.separator") + 
							getXmlResourceFilename());
			parser.parse("file://" + 
							WebMailServer.getServer().getProperty("webmail.template.path") + 
							System.getProperty("file.separator") + 
							getXmlResourceFilename());
	
			xmlRoot = parser.getDocument(); 
			
			NodeList nl = xmlRoot.getElementsByTagName("COMMON");
			if (nl.getLength() > 0) {
				elem_common=(Element)nl.item(0);
			} 

			nl = xmlRoot.getElementsByTagName("LOCALE");
			if (nl.getLength() > 0) {
				elementBundle = (Element)nl.item(0);
			} 
		}
		catch (IOException e) {
			System.err.println(e);
		} 
		catch (SAXException e) {
			System.err.println(e);
		}
	}

	protected void getKeys(Element element, Hashtable hash) {
		NodeList nl = element.getElementsByTagName("RESOURCE");
		for (int i=0; i < nl.getLength(); i++) {
			hash.put(((Element)nl.item(i)).getAttribute("name"), "");
		}
	}
	
	protected String getResult(Element element, String key) {
		NodeList nl = element.getElementsByTagName("RESOURCE");
		for(int i = 0; i < nl.getLength(); i++) {
			Element e = (Element)nl.item(i);
			if (e.getAttribute("name").equals(key)) {
				String s="";
				NodeList textl = e.getChildNodes();
				for (int j=0; j < textl.getLength(); j++) {
					if (debug)
						System.err.println("XMLResourceBundle ("+key+"): Type "+textl.item(j).getNodeName());
					if (textl.item(j).getNodeName().equals("#text") ||
						textl.item(j).getNodeName().equals("#cdata-section")) {
						s += textl.item(j).getNodeValue();
					}
				}
				return s;
			}
		}
		return null;
	}
}