/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2009 by ELCA Informatique SA, Av. de la Harpe 22-24,
    * 1000 Lausanne, Switzerland, http://www.elca.ch
    *
    * EL4J is published under the GNU Lesser General Public License (LGPL)
    * Version 2.1. See http://www.gnu.org/licenses/
    *
   * 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 Lesser General Public License for more details.
   *
   * For alternative licensing, please contact info@elca.ch
   */
  package ch.elca.el4j.env.xml;
  
  import java.util.Map;
  
  import org.springframework.core.io.Resource;
  import org.xml.sax.Attributes;
  import org.xml.sax.SAXException;
  import org.xml.sax.helpers.DefaultHandler;
  
  import ch.elca.el4j.env.xml.handlers.EnvGroupHandler;
  
  /**
   * The main SAX handler to parse the env.xml file.
   * It delegates the env group sections to the handlers specified in the constructor.
   *
   * @svnLink $Revision: 3874 $;$Date: 2009-08-04 14:25:40 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/env/src/main/java/ch/elca/el4j/env/xml/EnvSaxHandler.java $
   *
   * @author Stefan Wismer (SWI)
   */
  public class EnvSaxHandler extends DefaultHandler {
  	/**
  	 * The env group handlers.
  	 */
  	private Map<String, EnvGroupHandler> m_handlers;
  	
  	/**
  	 * The active group handler.
  	 */
  	private EnvGroupHandler m_currentGroupHandler;
  	
  	/**
  	 * The current depth in the XML tree.
  	 */
  	private int m_depth = 0;
  	
  	/**
  	 * @param handlers    the handlers that handle a specific env group (e.g. "placeholders" -> PlaceholdersHandler).
  	 */
  	public EnvSaxHandler(Map<String, EnvGroupHandler> handlers) {
  		m_handlers = handlers;
  	}
  	
  	/**
  	 * Notify which resource will be parsed next.
  	 * @param resource    the resource that will be parsed next
  	 */
  	public void startResource(Resource resource) {
  		for (EnvGroupHandler handler : m_handlers.values()) {
  			if (handler != null) {
  				handler.startResource(resource);
  			}
  		}
  	}
  	
  	/** {@inheritDoc} */
  	@Override
  	public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
  		if (m_depth == 0) {
  			assert qName.equals("env");
  		} else if (m_depth == 1) {
  			if (qName.equals("group")) {
  				m_currentGroupHandler = m_handlers.get(attributes.getValue("type"));
  			} else {
  				m_currentGroupHandler = m_handlers.get(qName);
  			}
  		} else if (m_currentGroupHandler != null) {
  			m_currentGroupHandler.startElement(uri, localName, qName, attributes);
  		}
  		m_depth++;
  	}
  	
  	/** {@inheritDoc} */
  	@Override
  	public void characters(char[] ch, int start, int length) throws SAXException {
  		if (m_currentGroupHandler != null) {
  			m_currentGroupHandler.characters(ch, start, length);
  		}
  	}
  	
  	/** {@inheritDoc} */
  	@Override
  	public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {
  		if (m_currentGroupHandler != null) {
 			m_currentGroupHandler.ignorableWhitespace(ch, start, length);
 		}
 	}
 	
 	/** {@inheritDoc} */
 	@Override
 	public void endElement(String uri, String localName, String name) throws SAXException {
 		if (m_currentGroupHandler != null) {
 			m_currentGroupHandler.endElement(uri, localName, name);
 		}
 		m_depth--;
 	}
 }