/*
    * $Id: I18nFactorySet.java 471754 2006-11-06 14:55:09Z husted $
    *
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  package org.apache.struts.tiles.xmlDefinition;
  
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.StringTokenizer;
  
  import javax.servlet.ServletContext;
  import javax.servlet.ServletRequest;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpSession;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.struts.tiles.taglib.ComponentConstants;
  import org.apache.struts.tiles.DefinitionsFactoryException;
  import org.apache.struts.tiles.FactoryNotFoundException;
  import org.xml.sax.SAXException;
  
  /**
   * Definitions factory.
   * This implementation allows to have a set of definition factories.
   * There is a main factory and one factory for each file associated to a Locale.
   *
   * To retrieve a definition, we first search for the appropriate factory using
   * the Locale found in session context. If no factory is found, use the
   * default one. Then we ask the factory for the definition.
   *
   * A definition factory file is loaded using main filename extended with locale code
   * (ex : <code>templateDefinitions_fr.xml</code>). If no file is found under this name, use default file.
   */
  public class I18nFactorySet extends FactorySet {
  
      /**
       * Commons Logging instance.
       */
      protected static Log log = LogFactory.getLog(I18nFactorySet.class);
  
      /**
       * Config file parameter name.
       */
      public static final String DEFINITIONS_CONFIG_PARAMETER_NAME =
          "definitions-config";
  
      /**
       * Config file parameter name.
       */
      public static final String PARSER_DETAILS_PARAMETER_NAME =
          "definitions-parser-details";
  
      /**
       * Config file parameter name.
       */
      public static final String PARSER_VALIDATE_PARAMETER_NAME =
          "definitions-parser-validate";
  
      /**
       * Possible definition filenames.
       */
      public static final String DEFAULT_DEFINITION_FILENAMES[] =
          {
              "/WEB-INF/tileDefinitions.xml",
              "/WEB-INF/componentDefinitions.xml",
              "/WEB-INF/instanceDefinitions.xml" };
  
      /**
       * Default filenames extension.
       */
      public static final String FILENAME_EXTENSION = ".xml";
  
      /**
       * Default factory.
      */
     protected DefinitionsFactory defaultFactory = null;
 
     /**
      * XML parser used.
      * Attribute is transient to allow serialization. In this implementaiton,
      * xmlParser is created each time we need it ;-(.
      */
     protected transient XmlParser xmlParser;
 
     /**
      * Do we want validating parser. Default is <code>false</code>.
      * Can be set from servlet config file.
      */
     protected boolean isValidatingParser = false;
 
     /**
      * Parser detail level. Default is 0.
      * Can be set from servlet config file.
      */
     protected int parserDetailLevel = 0;
 
     /**
      * Names of files containing instances descriptions.
      */
     private List filenames = null;
 
     /**
      * Collection of already loaded definitions set, referenced by their suffix.
      */
     private Map loaded = null;
 
     /**
      * Parameterless Constructor.
      * Method {@link #initFactory} must be called prior to any use of created factory.
      */
     public I18nFactorySet() {
         super();
     }
 
     /**
      * Constructor.
      * Init the factory by reading appropriate configuration file.
      * @param servletContext Servlet context.
      * @param properties Map containing all properties.
      * @throws FactoryNotFoundException Can't find factory configuration file.
      */
     public I18nFactorySet(ServletContext servletContext, Map properties)
         throws DefinitionsFactoryException {
 
         initFactory(servletContext, properties);
     }
 
     /**
      * Initialization method.
      * Init the factory by reading appropriate configuration file.
      * This method is called exactly once immediately after factory creation in
      * case of internal creation (by DefinitionUtil).
      * @param servletContext Servlet Context passed to newly created factory.
      * @param properties Map of name/property passed to newly created factory. Map can contains
      * more properties than requested.
      * @throws DefinitionsFactoryException An error occur during initialization.
      */
     public void initFactory(ServletContext servletContext, Map properties)
         throws DefinitionsFactoryException {
 
         // Set some property values
         String value = (String) properties.get(PARSER_VALIDATE_PARAMETER_NAME);
         if (value != null) {
             isValidatingParser = Boolean.valueOf(value).booleanValue();
         }
 
         value = (String) properties.get(PARSER_DETAILS_PARAMETER_NAME);
         if (value != null) {
             try {
                 parserDetailLevel = Integer.valueOf(value).intValue();
 
             } catch (NumberFormatException ex) {
                 log.error(
                     "Bad format for parameter '"
                         + PARSER_DETAILS_PARAMETER_NAME
                         + "'. Integer expected.");
             }
         }
 
         // init factory withappropriate configuration file
         // Try to use provided filename, if any.
         // If no filename are provided, try to use default ones.
         String filename = (String) properties.get(DEFINITIONS_CONFIG_PARAMETER_NAME);
         if (filename != null) { // Use provided filename
             try {
                 initFactory(servletContext, filename);
                 if (log.isDebugEnabled()) {
                     log.debug("Factory initialized from file '" + filename + "'.");
                 }
 
             } catch (FileNotFoundException ex) { // A filename is specified, throw appropriate error.
                 log.error(ex.getMessage() + " : Can't find file '" + filename + "'");
                 throw new FactoryNotFoundException(
                     ex.getMessage() + " : Can't find file '" + filename + "'");
             }
 
         } else { // try each default file names
             for (int i = 0; i < DEFAULT_DEFINITION_FILENAMES.length; i++) {
                 filename = DEFAULT_DEFINITION_FILENAMES[i];
                 try {
                     initFactory(servletContext, filename);
                     if (log.isInfoEnabled()) {
                         log.info(
                             "Factory initialized from file '" + filename + "'.");
                     }
                 } catch (FileNotFoundException ex) {
                     // Do nothing
                 }
             }
         }
 
     }
 
     /**
      * Initialization method.
      * Init the factory by reading appropriate configuration file.
      * This method is called exactly once immediately after factory creation in
      * case of internal creation (by DefinitionUtil).
      * @param servletContext Servlet Context passed to newly created factory.
      * @param proposedFilename File names, comma separated, to use as  base file names.
      * @throws DefinitionsFactoryException An error occur during initialization.
      */
     protected void initFactory(
         ServletContext servletContext,
         String proposedFilename)
         throws DefinitionsFactoryException, FileNotFoundException {
 
         // Init list of filenames
         StringTokenizer tokenizer = new StringTokenizer(proposedFilename, ",");
         this.filenames = new ArrayList(tokenizer.countTokens());
         while (tokenizer.hasMoreTokens()) {
             this.filenames.add(tokenizer.nextToken().trim());
         }
 
         loaded = new HashMap();
         defaultFactory = createDefaultFactory(servletContext);
         if (log.isDebugEnabled())
             log.debug("default factory:" + defaultFactory);
     }
 
     /**
      * Get default factory.
      * @return Default factory
      */
     protected DefinitionsFactory getDefaultFactory() {
         return defaultFactory;
     }
 
     /**
      * Create default factory .
      * Create InstancesMapper for specified Locale.
      * If creation failes, use default mapper and log error message.
      * @param servletContext Current servlet context. Used to open file.
      * @return Created default definition factory.
      * @throws DefinitionsFactoryException If an error occur while creating factory.
      * @throws FileNotFoundException if factory can't be loaded from filenames.
      */
     protected DefinitionsFactory createDefaultFactory(ServletContext servletContext)
         throws DefinitionsFactoryException, FileNotFoundException {
 
         XmlDefinitionsSet rootXmlConfig = parseXmlFiles(servletContext, "", null);
         if (rootXmlConfig == null) {
             throw new FileNotFoundException();
         }
 
         rootXmlConfig.resolveInheritances();
 
         if (log.isDebugEnabled()) {
             log.debug(rootXmlConfig);
         }
 
         DefinitionsFactory factory = new DefinitionsFactory(rootXmlConfig);
         if (log.isDebugEnabled()) {
             log.debug("factory loaded : " + factory);
         }
 
         return factory;
     }
 
     /**
      * Extract key that will be used to get the sub factory.
      * @param name Name of requested definition
      * @param request Current servlet request.
      * @param servletContext Current servlet context.
      * @return the key or <code>null</code> if not found.
      */
     protected Object getDefinitionsFactoryKey(
         String name,
         ServletRequest request,
         ServletContext servletContext) {
 
         Locale locale = null;
         try {
             HttpSession session = ((HttpServletRequest) request).getSession(false);
             if (session != null) {
                 locale = (Locale) session.getAttribute(ComponentConstants.LOCALE_KEY);
             }
 
         } catch (ClassCastException ex) {
             log.error("I18nFactorySet.getDefinitionsFactoryKey");
             ex.printStackTrace();
         }
 
         return locale;
     }
 
     /**
      * Create a factory for specified key.
     * If creation failes, return default factory and log an error message.
     * @param key The key.
     * @param request Servlet request.
     * @param servletContext Servlet context.
     * @return Definition factory for specified key.
     * @throws DefinitionsFactoryException If an error occur while creating factory.
      */
     protected DefinitionsFactory createFactory(
         Object key,
         ServletRequest request,
         ServletContext servletContext)
         throws DefinitionsFactoryException {
 
         if (key == null) {
             return getDefaultFactory();
         }
 
         // Build possible postfixes
         List possiblePostfixes = calculateSuffixes((Locale) key);
 
         // Search last postix corresponding to a config file to load.
         // First check if something is loaded for this postfix.
         // If not, try to load its config.
         XmlDefinitionsSet lastXmlFile = null;
         DefinitionsFactory factory = null;
         String curPostfix = null;
         int i = 0;
 
         for (i = possiblePostfixes.size() - 1; i >= 0; i--) {
             curPostfix = (String) possiblePostfixes.get(i);
 
             // Already loaded ?
             factory = (DefinitionsFactory) loaded.get(curPostfix);
             if (factory != null) { // yes, stop search
                 return factory;
             }
 
             // Try to load it. If success, stop search
             lastXmlFile = parseXmlFiles(servletContext, curPostfix, null);
             if (lastXmlFile != null) {
                 break;
             }
         }
 
         // Have we found a description file ?
         // If no, return default one
         if (lastXmlFile == null) {
             return getDefaultFactory();
         }
 
         // We found something. Need to load base and intermediate files
         String lastPostfix = curPostfix;
         XmlDefinitionsSet rootXmlConfig = parseXmlFiles(servletContext, "", null);
         for (int j = 0; j < i; j++) {
             curPostfix = (String) possiblePostfixes.get(j);
             parseXmlFiles(servletContext, curPostfix, rootXmlConfig);
         }
 
         rootXmlConfig.extend(lastXmlFile);
         rootXmlConfig.resolveInheritances();
 
         factory = new DefinitionsFactory(rootXmlConfig);
         loaded.put(lastPostfix, factory);
 
         if (log.isDebugEnabled()) {
             log.debug("factory loaded : " + factory);
         }
 
         // return last available found !
         return factory;
     }
 
     /**
      * Calculate the suffixes based on the locale.
      * @param locale the locale
      */
     private List calculateSuffixes(Locale locale) {
 
         List suffixes = new ArrayList(3);
         String language = locale.getLanguage();
         String country  = locale.getCountry();
         String variant  = locale.getVariant();
 
         StringBuffer suffix = new StringBuffer();
         suffix.append('_');
         suffix.append(language);
         if (language.length() > 0) {
             suffixes.add(suffix.toString());
         }
 
         suffix.append('_');
         suffix.append(country);
         if (country.length() > 0) {
             suffixes.add(suffix.toString());
         }
 
         suffix.append('_');
         suffix.append(variant);
         if (variant.length() > 0) {
             suffixes.add(suffix.toString());
         }
 
         return suffixes;
 
     }
 
     /**
      * Parse files associated to postix if they exist.
      * For each name in filenames, append postfix before file extension,
      * then try to load the corresponding file.
      * If file doesn't exist, try next one. Each file description is added to
      * the XmlDefinitionsSet description.
      * The XmlDefinitionsSet description is created only if there is a definition file.
      * Inheritance is not resolved in the returned XmlDefinitionsSet.
      * If no description file can be opened and no definiion set is provided, return <code>null</code>.
      * @param postfix Postfix to add to each description file.
      * @param xmlDefinitions Definitions set to which definitions will be added. If <code>null</code>, a definitions
      * set is created on request.
      * @return XmlDefinitionsSet The definitions set created or passed as parameter.
      * @throws DefinitionsFactoryException On errors parsing file.
      */
     protected XmlDefinitionsSet parseXmlFiles(
         ServletContext servletContext,
         String postfix,
         XmlDefinitionsSet xmlDefinitions)
         throws DefinitionsFactoryException {
 
         if (postfix != null && postfix.length() == 0) {
             postfix = null;
         }
 
         // Iterate throw each file name in list
         Iterator i = filenames.iterator();
         while (i.hasNext()) {
             String filename = concatPostfix((String) i.next(), postfix);
             xmlDefinitions = parseXmlFile(servletContext, filename, xmlDefinitions);
         }
 
         return xmlDefinitions;
     }
 
     /**
      * Parse specified xml file and add definition to specified definitions set.
      * This method is used to load several description files in one instances list.
      * If filename exists and definition set is <code>null</code>, create a new set. Otherwise, return
      * passed definition set (can be <code>null</code>).
      * @param servletContext Current servlet context. Used to open file.
      * @param filename Name of file to parse.
      * @param xmlDefinitions Definitions set to which definitions will be added. If null, a definitions
      * set is created on request.
      * @return XmlDefinitionsSet The definitions set created or passed as parameter.
      * @throws DefinitionsFactoryException On errors parsing file.
      */
     protected XmlDefinitionsSet parseXmlFile(
         ServletContext servletContext,
         String filename,
         XmlDefinitionsSet xmlDefinitions)
         throws DefinitionsFactoryException {
 
         try {
             InputStream input = servletContext.getResourceAsStream(filename);
             // Try to load using real path.
             // This allow to load config file under websphere 3.5.x
             // Patch proposed Houston, Stephen (LIT) on 5 Apr 2002
             if (null == input) {
                 try {
                     input =
                         new java.io.FileInputStream(
                             servletContext.getRealPath(filename));
                 } catch (Exception e) {
                 }
             }
 
             // If the config isn't in the servlet context, try the class loader
             // which allows the config files to be stored in a jar
             if (input == null) {
                 input = getClass().getResourceAsStream(filename);
             }
 
             // If still nothing found, this mean no config file is associated
             if (input == null) {
                 if (log.isDebugEnabled()) {
                     log.debug("Can't open file '" + filename + "'");
                 }
                 return xmlDefinitions;
             }
 
             // Check if parser already exist.
             // Doesn't seem to work yet.
             //if( xmlParser == null )
             if (true) {
                 xmlParser = new XmlParser();
                 xmlParser.setValidating(isValidatingParser);
             }
 
             // Check if definition set already exist.
             if (xmlDefinitions == null) {
                 xmlDefinitions = new XmlDefinitionsSet();
             }
 
             xmlParser.parse(input, xmlDefinitions);
 
         } catch (SAXException ex) {
             if (log.isDebugEnabled()) {
                 log.debug("Error while parsing file '" + filename + "'.");
                 ex.printStackTrace();
             }
             throw new DefinitionsFactoryException(
                 "Error while parsing file '" + filename + "'. " + ex.getMessage(),
                 ex);
 
         } catch (IOException ex) {
             throw new DefinitionsFactoryException(
                 "IO Error while parsing file '" + filename + "'. " + ex.getMessage(),
                 ex);
         }
 
         return xmlDefinitions;
     }
 
     /**
      * Concat postfix to the name. Take care of existing filename extension.
      * Transform the given name "name.ext" to have "name" + "postfix" + "ext".
      * If there is no ext, return "name" + "postfix".
      * @param name Filename.
      * @param postfix Postfix to add.
      * @return Concatenated filename.
      */
     private String concatPostfix(String name, String postfix) {
         if (postfix == null) {
             return name;
         }
 
         // Search file name extension.
         // take care of Unix files starting with .
         int dotIndex = name.lastIndexOf(".");
         int lastNameStart = name.lastIndexOf(java.io.File.pathSeparator);
         if (dotIndex < 1 || dotIndex < lastNameStart) {
             return name + postfix;
         }
 
         String ext = name.substring(dotIndex);
         name = name.substring(0, dotIndex);
         return name + postfix + ext;
     }
 
     /**
      * Return String representation.
      * @return String representation.
      */
     public String toString() {
         StringBuffer buff = new StringBuffer("I18nFactorySet : \n");
         buff.append("--- default factory ---\n");
         buff.append(defaultFactory.toString());
         buff.append("\n--- other factories ---\n");
         Iterator i = factories.values().iterator();
         while (i.hasNext()) {
             buff.append(i.next().toString()).append("---------- \n");
         }
         return buff.toString();
     }
 
 }