/*
    * 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.core.io.support;
  
  import java.io.IOException;
  import java.net.URL;
  import java.util.ArrayList;
  import java.util.Enumeration;
  import java.util.List;
  import java.util.StringTokenizer;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.core.io.ClassPathResource;
  import org.springframework.core.io.Resource;
  import org.springframework.util.ClassUtils;
  import org.springframework.util.StringUtils;
  
  import ch.elca.el4j.core.io.ExplicitClassPathResource;
  
  /**
   * This class represents a simplified view of a module (EL4Ant build system
   * unit). It contains its name, the configuration files and the dependencies.
   *
   * @svnLink $Revision: 3881 $;$Date: 2009-08-04 15:22:05 +0200 (Di, 04. Aug 2009) $;$Author: swismer $;$URL: https://el4j.svn.sourceforge.net/svnroot/el4j/branches/el4j_3_1/el4j/framework/modules/core/src/main/java/ch/elca/el4j/core/io/support/Module.java $
   *
   * @author Andreas Bur (ABU)
   */
  public class Module {
  	
  	/** The delimiter used to separate configuration files and dependencies. */
  	public static final String DELIMITER = ",";
  	
  	/** Private logger. */
  	private static Logger s_logger = LoggerFactory.getLogger(Module.class);
  	
  	/**
  	 * Is the used class loader.
  	 */
  	protected final ClassLoader m_classLoader;
  	
  	/**
  	 * The module's name.
  	 */
  	private final String m_name;
  	
  	/**
  	 * The module's location.
  	 */
  	private final String m_moduleLocation;
  	
  	/**
  	 * The module's configuration files.
  	 */
  	private List<String> m_configFiles;
  	
  	/**
  	 * The module's config file resources.
  	 * Like {@link #m_configFiles} but with resolved resources.
  	 */
  	private List<Resource> m_configFileResources;
  	
  	/**
  	 * The module's dependencies.
  	 */
  	private List<String> m_dependencies;
  	
  	/**
  	 * Creates a new module with the given name.
  	 *
  	 * @param name
  	 *      The module's name.
  	 */
  	public Module(String name) {
  		this(name, null, null);
  	}
  	
  	/**
  	 * Creates a new module with the given name and the module's location.
  	 *
  	 * @param name The module's name.
  	 * @param moduleLocation The module's location.
  	 */
  	public Module(String name, String moduleLocation) {
 		this(name, moduleLocation, null);
 	}
 	
 	/**
 	 * Creates a new module with the given name, the module's location
 	 * and resolves resources by using the given class loader.
 	 *
 	 * @param name The module's name.
 	 * @param moduleLocation The module's location.
 	 * @param classLoader The class loader to resolve resources.
 	 */
 	public Module(String name, String moduleLocation, ClassLoader classLoader) {
 		m_name = name;
 		m_moduleLocation = StringUtils.hasText(moduleLocation)
 			? moduleLocation : null;
 		m_configFiles = new ArrayList<String>();
 		m_configFileResources = new ArrayList<Resource>();
 		m_dependencies = new ArrayList<String>();
 		m_classLoader = classLoader != null
 			? classLoader : ClassUtils.getDefaultClassLoader();
 	}
 	
 	/**
 	 * Adds all items -- separated by {@link #DELIMITER} -- to the configuration
 	 * file list.
 	 *
 	 * @param configFiles
 	 *      The list of configuration files to add.
 	 */
 	public void addAllConfigFiles(String configFiles) {
 		StringTokenizer tokenizer = new StringTokenizer(configFiles, DELIMITER);
 		while (tokenizer.hasMoreTokens()) {
 			addConfigFile(tokenizer.nextToken());
 		}
 	}
 	
 	/**
 	 * Adds the given configuration file to the module.
 	 *
 	 * @param configFile
 	 *      The configuration file to add.
 	 */
 	public void addConfigFile(String configFile) {
 		m_configFiles.add(configFile);
 		m_configFileResources.add(getConfigFileAsResource(configFile));
 	}
 	
 	/**
 	 * Adds all item -- separated by {@link #DELIMITER} -- to the dependency
 	 * list.
 	 *
 	 * @param dependencies
 	 *      The list of dependencies to add.
 	 */
 	public void addAllDependencies(String dependencies) {
 		StringTokenizer tokenizer = new StringTokenizer(
 				dependencies, DELIMITER);
 		while (tokenizer.hasMoreTokens()) {
 			addDependency(tokenizer.nextToken());
 		}
 	}
 	
 	/**
 	 * Adds the given dependency to the module.
 	 *
 	 * @param dependency
 	 *      The dependency to add.
 	 */
 	public void addDependency(String dependency) {
 		m_dependencies.add(dependency);
 	}
 	
 	/**
 	 * @return Returns all configuration files.
 	 */
 	public String[] getConfigFiles() {
 		return (String[]) m_configFiles.toArray(
 				new String[m_configFiles.size()]);
 	}
 	
 	/**
 	 * @return Returns all dependencies.
 	 */
 	public String[] getDependencies() {
 		return (String[]) m_dependencies.toArray(
 				new String[m_dependencies.size()]);
 	}
 	
 	/**
 	 * @return Returns the configuration file list.
 	 */
 	public List<String> getConfigFilesAsList() {
 		return new ArrayList<String>(m_configFiles);
 	}
 	
 	/**
 	 * @return Returns the dependency list.
 	 */
 	public List<String> getDependenciesAsList() {
 		return new ArrayList<String>(m_dependencies);
 	}
 	
 	/**
 	 * @return Returns the module's name.
 	 */
 	public String getName() {
 		return m_name;
 	}
 	
 	/**
 	 * @return Returns the module's location.
 	 */
 	public String getModuleLocation() {
 		return m_moduleLocation;
 	}
 	
 	/**
 	 * @return Returns the configuration files resolved as resources in a list.
 	 */
 	public List<Resource> getConfigFileResourcesAsList() {
 		return new ArrayList<Resource>(m_configFileResources);
 	}
 	
 	/**
 	 * Converts the given config file in a resource that takes place in
 	 * the current module.
 	 *
 	 * @param configFile The config file to convert.
 	 * @return Returns the converted resource.
 	 */
 	public Resource getConfigFileAsResource(String configFile) {
 		Resource resource = null;
 		if (m_moduleLocation == null) {
 			resource = new ClassPathResource(configFile);
 		} else {
 			try {
 				Enumeration<URL> resources
 					= m_classLoader.getResources(configFile);
 				while (resources.hasMoreElements() && resource == null) {
 					URL url = resources.nextElement();
 					String urlString = url.getFile();
 					if (urlString.startsWith(m_moduleLocation)) {
 						resource = new ExplicitClassPathResource(
 							url, configFile, m_classLoader);
 					}
 				}
 			} catch (IOException e) {
 				resource = null;
 			}
 			if (resource == null) {
 				s_logger.warn("Config file '" + configFile
 					+ "' could not be resolved with current class loader.");
 				resource = new ClassPathResource(configFile);
 			}
 		}
 		return resource;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	public String toString() {
 		if (m_moduleLocation != null) {
 			return "Module '" + m_name + "' at '" + m_moduleLocation + "'";
 		} else {
 			return "Module '" + m_name + "'";
 		}
 	}
 }