/*
    * 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.handlers;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Properties;
  
  import org.springframework.core.io.Resource;
  import org.xml.sax.Attributes;
  import org.xml.sax.helpers.DefaultHandler;
  
  import ch.elca.el4j.env.InvalidEnvXmlContentException;
  import ch.elca.el4j.env.xml.ResolverUtils;
  
  /**
   * An {@link EnvGroupHandler} that handles inheritable properties (which can also be abstract or final).
   *
   * @svnLink $Revision: 3873 $;$Date: 2009-08-04 13:59:45 +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/handlers/AbstractInheritablePropertyHandler.java $
   *
   * @author Stefan Wismer (SWI)
   */
  public abstract class AbstractInheritablePropertyHandler extends DefaultHandler implements EnvGroupHandler {
  	/**
  	 * The ordinary properties.
  	 */
  	protected Properties m_properties = new Properties();
  	
  	/**
  	 * The abstract property names and the resource they are declared.
  	 */
  	protected Map<String, Resource> m_abstractProperties = new HashMap<String, Resource>();
  	
  	/**
  	 * The final property names and the resource they are declared.
  	 */
  	protected Map<String, Resource> m_finalProperties = new HashMap<String, Resource>();
  	
  	/**
  	 * The resource currently being propcessed. 
  	 */
  	protected Resource m_currentResource;
  	
  	/** {@inheritDoc} */
  	public void startResource(Resource resource) {
  		m_currentResource = resource;
  	}
  	
  	/**
  	 * Add a property given by an xml tag having the attributes 'name' (required), 'value' and 'type'.
  	 * @param attributes    the tag attributes
  	 */
  	protected void addProperty(Attributes attributes) {
  		String entryName = attributes.getValue("name");
  		String entryValue = attributes.getValue("value");
  		String entryType = attributes.getValue("type");
  		
  		if (entryValue == null) {
  			entryValue = "${" + entryName + "}";
  		}
  		
  		if ("abstract".equalsIgnoreCase(entryType)) {
  			m_abstractProperties.put(entryName, m_currentResource);
  		} else {
  			if ("final".equalsIgnoreCase(entryType)) {
  				m_properties.put(entryName, entryValue);
  				m_finalProperties.put(entryName, m_currentResource);
  			} else {
  				if (m_finalProperties.containsKey(entryName)) {
  					throw new InvalidEnvXmlContentException(
  						"It is not allowed to overwrite final property '" + entryName + "' in "
  						+ m_currentResource.toString()
  						+ ".\nAlternatively, you might want to recompile artifact containing '"
  						+ m_finalProperties.get(entryName).toString());
  				}
  			}
  			m_abstractProperties.remove(entryName);
  			m_properties.put(entryName, entryValue);
  		}
  	}
  	
  	/**
  	 * Remove a property given by an xml tag having the attribute 'name' (required).
  	 * @param attributes    the tag attributes
  	 */
 	protected void removeProperty(Attributes attributes) {
 		String entryName = attributes.getValue("name");
 		m_properties.remove(entryName);
 		m_abstractProperties.remove(entryName);
 		m_finalProperties.remove(entryName);
 	}
 	
 	/** {@inheritDoc} */
 	public void filterData(Properties properties) {
 		for (Object objectKey : m_properties.keySet()) {
 			String key = (String) objectKey;
 			String value = m_properties.getProperty(key);
 			
 			String resolvedValue;
 			if (m_finalProperties.containsKey(key)) {
 				resolvedValue = properties.getProperty(key);
 			} else {
 				resolvedValue = ResolverUtils.resolve(value, properties);
 				
 				// add property to resolved properties map
 				properties.setProperty(key, resolvedValue);
 			}
 			m_properties.setProperty(key, resolvedValue);
 		}
 	}
 	
 	
 	/** {@inheritDoc} */
 	public Object getData() {
 		// env plugin already warns if it detects abstract properties
 		/*if (!m_abstractProperties.isEmpty()) {
 			for (String abstractProperty : m_abstractProperties.keySet()) {
 				s_logger.warn(
 					"Abstract property '" + abstractProperty + "' defined in '"
 					+ m_abstractProperties.get(abstractProperty).toString() + "' must be set.");
 			}
 		}*/
 		return m_properties;
 	}
 }