/*
    * EL4J, the Extension Library for the J2EE, adds incremental enhancements to
    * the spring framework, http://el4j.sf.net
    * Copyright (C) 2005 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.web.context;
  
  import org.springframework.beans.BeansException;
  import org.springframework.util.StringUtils;
  import org.springframework.web.context.ConfigurableWebApplicationContext;
  import org.springframework.web.context.WebApplicationContext;
  import org.springframework.web.servlet.DispatcherServlet;
  
  /**
   * This class extends Springs <code>DispatcherServlet</code>. It inherits the
   * its complete behaviour but replaces the web application context with a
   * {@link ch.elca.el4j.web.context.ModuleWebApplicationContext} which
   * preserves the order of module dependencies when resources are resolved.
   *
   * @svnLink $Revision: 4204 $;$Date: 2010-11-02 11:44:37 +0100 (Di, 02. Nov 2010) $;$Author: swisswheel $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/web/jar/src/main/java/ch/elca/el4j/web/context/ModuleDispatcherServlet.java $
   *
   * @author Andreas Bur (ABU)
   */
  public class ModuleDispatcherServlet extends DispatcherServlet {
  	/**
  	 * Generated serial version UID.
  	 */
  	private static final long serialVersionUID = 2583279389917262839L;
  
  	/**
  	 * The configuration locations that are included to initialize the
  	 * application context.
  	 */
  	private String m_inclusiveLocations;
  	
  	/**
  	 * The configuration locations that are excluded during the application
  	 * context's initialization.
  	 */
  	private String m_exclusiveLocations;
  	
  	/** Holds whether overriding of already defined beans is allowed. */
  	private boolean m_allowBeanDefinitionOverriding = false;
  
  	/**
  	 * Whether to merge the configuration locations defined in the manifest
  	 * files have to be merged with files looked up in the file system.
  	 */
  	private boolean m_mergeWithOuterResources = false;
  	
  	/**
  	 * {@inheritDoc}
  	 */
  	protected WebApplicationContext createWebApplicationContext(
  			WebApplicationContext parent) throws BeansException {
  		
  		if (logger.isDebugEnabled()) {
  			logger.debug("Servlet with name '" + getServletName()
  					+ "' will try to create custom WebApplicationContext "
  					+ "context of class '" + getContextClass().getName() + "'"
  					+ ", using parent context [" + parent + "]");
  		}
  
  		String[] incl = toStringArray(getInclusiveLocations());
  		String[] excl = toStringArray(getExclusiveLocations());
  		
  		ModuleWebApplicationContext wac
  			= new ModuleWebApplicationContext(incl, excl,
  					isAllowBeanDefinitionOverriding(),
  					getServletContext(),
  					m_mergeWithOuterResources, parent);
  		
  		wac.setNamespace(getNamespace());
  		wac.refresh();
  		return wac;
  	}
  
  	/**
  	 * Sets whether it's allowed to override bean definitions, as it may happen
  	 * by using the same bean name in different configuration files, which
  	 * are loaded sequentially.
  	 *
  	 * @param allowBeanDefinitionOverriding
  	 *      Whether it's allowed to override bean definitions.
  	 */
  	public void setAllowBeanDefinitionOverriding(
  			boolean allowBeanDefinitionOverriding) {
 		
 		m_allowBeanDefinitionOverriding = allowBeanDefinitionOverriding;
 	}
 
 	/**
 	 * Sets the list of configuration files that have to be excluded from
 	 * the application context's configuration.
 	 *
 	 * @param exclusiveLocations
 	 *      Configuration locations to exclude.
 	 */
 	public void setExclusiveLocations(String exclusiveLocations) {
 		m_exclusiveLocations = exclusiveLocations;
 	}
 
 	/**
 	 * Sets the list of configuration files that have to be included when the
 	 * application context is initialized.
 	 *
 	 * @param inclusiveLocations
 	 *      Configuration locations to include.
 	 */
 	public void setInclusiveLocations(String inclusiveLocations) {
 		m_inclusiveLocations = inclusiveLocations;
 	}
 	
 	/**
 	 * @return Returns whether it's allowed to override already exisiting
 	 *      bean definitions.
 	 */
 	public boolean isAllowBeanDefinitionOverriding() {
 		return m_allowBeanDefinitionOverriding;
 	}
 
 	/**
 	 * @return Returns the list of configuration locations that are excluded
 	 *      when the application context is initialized.
 	 */
 	public String getExclusiveLocations() {
 		return m_exclusiveLocations;
 	}
 
 	/**
 	 * @return Returns the list of configuration locations that are used to
 	 *      initialize the application context.
 	 */
 	public String getInclusiveLocations() {
 		String result;
 		if (m_inclusiveLocations == null) {
 			result = super.getContextConfigLocation();
 		} else {
 			result = m_inclusiveLocations;
 		}
 		return result;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	public String getContextConfigLocation() {
 		return m_inclusiveLocations;
 	}
 
 	/**
 	 * @return Returns <code>true</code> if the resource pattern resolver merges
 	 *      items found in the manifest configuration section with items found
 	 *      in the file system. <code>false</code> otherwise.
 	 */
 	public boolean isMergeWithOuterResources() {
 		return m_mergeWithOuterResources;
 	}
 
 	/**
 	 * Sets whether configuration locations retrieved by the pattern resolver
 	 * have to be merged with resources looked up in the file system.
 	 *
 	 * @param mergeWithOuterResources
 	 *      <code>true</code> for merging configuration locations provided
 	 *      through the manifest file with resources looked up in the file
 	 *      system. <code>false</code> otherwise.
 	 */
 	public void setMergeWithOuterResources(boolean mergeWithOuterResources) {
 		m_mergeWithOuterResources = mergeWithOuterResources;
 	}
 
 	/**
 	 * Transforms a string of tokens into a string array. The tokens have to
 	 * be separated by {@link
 	 * ConfigurableWebApplicationContext#CONFIG_LOCATION_DELIMITERS}.
 	 *
 	 * @param str
 	 *      The string to parse.
 	 *
 	 * @return Returns the given string's token as array.
 	 */
 	private String[] toStringArray(String str) {
 		String[] result = new String[0];
 		if (str != null) {
 			result =  StringUtils.tokenizeToStringArray(str,
 				ConfigurableWebApplicationContext.CONFIG_LOCATION_DELIMITERS);
 		}
 		return result;
 	}
 }