/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2006 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.services.xmlmerge.springframework;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.List;
  import java.util.Map;
  
  import org.springframework.core.io.AbstractResource;
  import org.springframework.core.io.Resource;
  
  import ch.elca.el4j.services.xmlmerge.AbstractXmlMergeException;
  import ch.elca.el4j.services.xmlmerge.ConfigurationException;
  import ch.elca.el4j.services.xmlmerge.XmlMerge;
  import ch.elca.el4j.services.xmlmerge.config.ConfigurableXmlMerge;
  import ch.elca.el4j.services.xmlmerge.config.PropertyXPathConfigurer;
  import ch.elca.el4j.services.xmlmerge.merge.DefaultXmlMerge;
  
  /**
   * A spring resource merging XML files read from other resources.
   *
   * @svnLink $Revision: 3884 $;$Date: 2009-08-04 15:48:31 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/xml_merge/common/src/main/java/ch/elca/el4j/services/xmlmerge/springframework/XmlMergeResource.java $
   *
   * @author Laurent Bovet (LBO)
   * @author Alex Mathey (AMA)
   */
  public class XmlMergeResource extends AbstractResource {
  	
  	/**
  	 * The list of resources to merge.
  	 */
  	List m_resources;
  	
  	/**
  	 * An XmlMerge instance used to merge the resources.
  	 */
  	XmlMerge m_xmlMerge;
  	
  	/**
  	 * Configuration properties.
  	 */
  	Map m_properties;
  		
  	/**
  	 * {@inheritDoc}
  	 */
  	public String getDescription() {
  		return "Resource merging other XML resources using XmlMerge";
  	}
  	
  	/**
  	 * Returns an InputStream containing the data of this merged resource.
  	 *
  	 * @return The InputStream containing the data of this merged resource.
  	 * @see org.springframework.core.io.AbstractResource
  	 */
  	public InputStream getInputStream() throws IOException {
  
  		if (m_properties == null) {
  			// Default configuration
  			m_xmlMerge = new DefaultXmlMerge();
  		} else {
  			try {
  				m_xmlMerge = new ConfigurableXmlMerge(
  					new PropertyXPathConfigurer(m_properties));
  			} catch (ConfigurationException e) {
  				throw new RuntimeException(e);
  			}
  		}
  
  		if (m_resources == null) {
  			throw new RuntimeException("Resources not set");
  		}
  
  		InputStream[] sources = new InputStream[m_resources.size()];
  
  		for (int i = 0; i < sources.length; i++) {
  			sources[i] = ((Resource) m_resources.get(i)).getInputStream();
  		}
  
  		try {
  			return m_xmlMerge.merge(sources);
  		} catch (AbstractXmlMergeException e) {
  			throw new RuntimeException(e);
 		}
 	}
 	 
 	/**
 	 * Sets the list of resources to merge.
 	 *
 	 * @param resources
 	 *            The list of resources to merge
 	 */
 	public void setResources(List resources) {
 		this.m_resources = resources;
 
 	}
 	 
 	/**
 	 * Sets the configuration properties.
 	 *
 	 * @param map
 	 *            A map containing the configuration properties
 	 */
 	public void setProperties(Map map) {
 		m_properties = map;
 	}
 
 }