/*
    * $Id: XmlConfigHandler.java 117 2004-10-23 18:42:03Z josem $
    *
    * Tarsis
    * Copyright (C) 2002 Talika Open Source Group
    *
    * This program is free software; you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  
  package org.talika.tarsis.context;
  
  import java.io.InputStream;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Stack;
  
  import org.talika.commons.util.BeanHelper;
  import org.talika.tarsis.command.factory.CommandFactoryService;
  import org.talika.tarsis.factory.FactoryService;
  import org.talika.tarsis.log.Logger;
  import org.talika.tarsis.log.LoggerService;
  import org.talika.tarsis.security.AuthenticatorService;
  import org.talika.tarsis.security.AuthorizatorService;
  import org.xml.sax.Attributes;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXParseException;
  import org.xml.sax.helpers.AttributesImpl;
  import org.xml.sax.helpers.DefaultHandler;
  
  /**
   * Loads context configuration from an XML file.
   *
   * @author  Jose M. Palomar
   * @version $Revision: 117 $
   */
  public final class XmlConfigHandler extends DefaultHandler {
  
      // Constants
      /**
       * <tarsis-config> tag.
       */
      public static final String CONFIG_TAG         = "tarsis-config";
  
      /**
       * <init-param> tag.
       */
      public static final String INIT_PARAM_TAG     = "init-param";
  
      /**
       * <security> tag.
       */
      public static final String SECURITY_TAG       = "security";
  
      /**
       * <authenticator> tag.
       */
      public static final String AUTHC_TAG          = "authenticator";
  
      /**
       * <authorizator> tag.
       */
      public static final String AUTHZ_TAG          = "authorizator";
  
      /**
       * <auth-param> tag.
       */
      public static final String AUTH_PARAM_TAG     = "auth-param";
  
      /**
       * <log> tag.
       */
      public static final String LOG_TAG            = "log";
  
      /**
       * <log-param> tag.
       */
      public static final String LOG_PARAM_TAG      = "log-param";
  
      /**
       * <factory> tag.
       */
     public static final String FACTORY_TAG        = "factory";
 
     /**
      * <factory-param> tag.
      */
     public static final String FACTORY_PARAM_TAG  = "factory-param";
 
    /**
     * <command-factory> tag.
     */
     public static final String CMD_FACTORY_TAG    = "command-factory";
 
     /**
      * <command-factory-param> tag.
      */
     public static final String CMD_FACTORY_PARAM_TAG = "command-factory-param";
 
     /**
      * Name attribute.
      */
     public static final String NAME_ATTR          = "name";
 
     /**
      * Class name attribute.
      */
     public static final String CLASS_NAME_ATTR    = "className";
 
     /**
      * Value attribute.
      */
     public static final String VALUE_ATTR         = "value";
 
     /**
      * Log level attribute.
      */
     public static final String LOG_LVL_ATTR       = "logLevel";
 
     /**
      * Preload attribute.
      */
     public static final String PRELOAD_ATTR       = "preload";
 
     /**
      * Debug log level value.
      */
     public static final String DEBUG_VALUE        = "debug";
 
     /**
      * Info log level value.
      */
     public static final String INFO_VALUE         = "info";
 
     /**
      * Warning log level value.
      */
     public static final String WARNING_VALUE      = "warning";
 
     /**
      * Error log level value.
      */
     public static final String ERROR_VALUE        = "error";
 
     /**
      * Panic log level value.
      */
     public static final String PANIC_VALUE        = "panic";
 
     /**
      * DTD public id.
      */
     public static final String DTD_PUBLICID = "-//Talika Open Source Group//Tarsis Config DTD 1.0//ES";
 
     /**
      * DTD class path.
      */
     public static final String DTD_CLASSPATH = "/org/talika/dtds/tarsis-config_1_0.dtd";
 
     // Fields
     /**
      * Parsed init parameters map.
      */
     private Map initParams;
 
     /**
      * Parsed <code>Factory</code> instances map.
      */
     private Map factories;
 
     /**
      * Parsed <code>Logger</code> instances list.
      */
     private List loggers;
 
     /**
      * Parsed <code>Authenticator</code> instance.
      */
     private AuthenticatorService authc;
 
     /**
      * Parsed <code>Authorizator</code> instance.
      */
     private AuthorizatorService authz;
 
     /**
      * Parsed <code>CommandFactory</code> instance.
      */
     private CommandFactoryService commandFactory;
 
     /**
      * Tag attributes stack.
      */
     private Stack stAtts = new Stack();
 
     /**
      * Auxiliar parameters map.
      */
     private Map auxParams = new HashMap();
 
     // Constructors
     /**
      * Creates a new <code>XmlConfigHandler</code> object.
      */
     public XmlConfigHandler() {
         this.initParams = new HashMap();
         this.factories = new HashMap();
         this.loggers = new LinkedList();
         this.stAtts = new Stack();
         this.auxParams = new HashMap();
     }
 
     // Methods
     // XML Handler
     /**
      * Receive notification of the beginning of a document.
      *
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ContentHandler#startDocument()
      */
     public void startDocument() throws SAXException {
         // Nothing to do
     }
 
     /**
      * Receive notification of the end of a document.
      *
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ContentHandler#endDocument()
      */
     public void endDocument() throws SAXException {
         // Nothing to do
     }
 
     /**
      * Receive notification of the beginning of an element.
      *
      * @param namespaceURI String The Namespace URI, or the empty string if the
      * element has no Namespace URI or if Namespace processing is not being performed.
      * @param localName String The local name (without prefix), or the empty string
      * if Namespace processing is not being performed.
      * @param name String The qualified name (with prefix), or the empty string if
      * qualified names are not available.
      * @param atts Attributes The attributes attached to the element. If there are no
      * attributes, it shall be an empty Attributes object.
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ContentHandler#startElement(String, String, String, Attributes)
      */
     public void startElement(String namespaceURI, String localName, String name, Attributes atts) throws SAXException {
         stAtts.push(new AttributesImpl(atts));
     }
 
     /**
      * Receive notification of the end of an element.
      *
      * @param namespaceURI String The Namespace URI, or the empty string if the
      * element has no Namespace URI or if Namespace processing is not being performed.
      * @param localName String The local name (without prefix), or the empty string
      * if Namespace processing is not being performed.
      * @param name String The qualified name (with prefix), or the empty string if
      * qualified names are not available.
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ContentHandler#endElement(String, String, String)
      */
     public void endElement(String namespaceURI, String localName, String name) throws SAXException {
 
         Attributes atts = (Attributes) stAtts.pop();
 
         if (name.equals(CONFIG_TAG)) {
             // Nothing to do
         }
         else if (name.equals(INIT_PARAM_TAG)) {
             processInitParamTag(atts);
         }
         else if (name.equals(SECURITY_TAG)) {
             // Nothing to do
         }
         else if (name.equals(AUTHC_TAG)) {
             processAuthenticatorTag(atts);
         }
         else if (name.equals(AUTHZ_TAG)) {
             processAuthorizatorTag(atts);
         }
         else if (name.equals(AUTH_PARAM_TAG)) {
             processParamTag(atts);
         }
         else if (name.equals(LOG_TAG)) {
             processLogTag(atts);
         }
         else if (name.equals(LOG_PARAM_TAG)) {
             processParamTag(atts);
         }
         else if (name.equals(FACTORY_TAG)) {
             processFactoryTag(atts);
         }
         else if (name.equals(FACTORY_PARAM_TAG)) {
             processParamTag(atts);
         }
         else if (name.equals(CMD_FACTORY_TAG)) {
             processCommandFactoryTag(atts);
         }
         else if (name.equals(CMD_FACTORY_PARAM_TAG)) {
             processParamTag(atts);
         }
 
     }
 
     // Entity Resolver
     /**
      * Allow the application to resolve external entities.
      *
      * @param publicId String The public identifier of the external entity being
      * referenced, or <code>null</code> if none was supplied.
      * @param systemId String The system identifier of the external entity being
      * referenced.
      * @return InputSource A Java-specific IO exception, possibly the result of
      * creating a new <code>InputStream</code> or <code>Reader</code> for the
      * <code>InputSource</code>.
      * @see org.xml.sax.EntityResolver#resolveEntity(String, String)
      */
     public InputSource resolveEntity (String publicId, String systemId) {
 
         if (publicId.equals(DTD_PUBLICID)) {
 
             InputStream is = this.getClass().getResourceAsStream(DTD_CLASSPATH);
             if (is != null) {
                 return new InputSource(is);
             }
 
         }
 
         return null;
 
     }
 
     // Error Handler
     /**
      * Receive notification of a warning.
      *
      * @param spe SAXParseException The warning information encapsulated in a SAX
      * parse exception.
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ErrorHandler#warning(SAXParseException)
      */
     public void warning(SAXParseException spe) throws SAXException {
     }
 
     /**
      * Receive notification of a recoverable error.
      *
      * @param spe SAXParseException The error information encapsulated in a SAX parse
      * exception.
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ErrorHandler#error(SAXParseException)
      */
     public void error(SAXParseException spe) throws SAXException {
         throw new SAXException("** Configuration parse error\n" +
                             "  at [" + spe.getLineNumber() +
                             ":" + spe.getColumnNumber() +
                             "] in " + spe.getSystemId(), spe);
     }
 
     /**
      * Receive notification of a non-recoverable error.
      *
      * @param spe SAXParseException The error information encapsulated in a SAX parse
      * exception.
      * @throws SAXException Any SAX exception, possibly wrapping another exception.
      * @see org.xml.sax.ErrorHandler#fatalError(SAXParseException)
      */
     public void fatalError(SAXParseException spe) throws SAXException {
         throw new SAXException("** Configuration parse error\n" +
                             "  at [" + spe.getLineNumber() +
                             ":" + spe.getColumnNumber() +
                             "] in " + spe.getSystemId(), spe);
     }
 
     // Accesors
     /**
      * Returns parsed init parameters map.
      *
      * @return Map parsed init parameters map.
      */
     public Map getInitParameters() {
         return Collections.unmodifiableMap(initParams);
     }
 
     /**
      * Returns parsed <code>Logger</code> instances list.
      *
      * @return Collection parsed <code>Logger</code> instances list.
      */
     public Collection getLoggers() {
         return Collections.unmodifiableCollection(loggers);
     }
 
     /**
      * Returns parsed <code>Authenticator</code> instance.
      *
      * @return AuthenticatorService parsed <code>Authenticator</code> instance or
      * <code>null</code> if none have been parsed.
      */
     public AuthenticatorService getAuthenticathor() {
         return authc;
     }
 
     /**
      * Returns parsed <code>Authorizator</code> instance.
      *
      * @return AuthorizatorService parsed <code>AuthorizatorService</code> instance
      * or <code>null</code> if non hava been parsed.
      */
     public AuthorizatorService getAuthorizator() {
         return authz;
     }
 
     /**
      * Returns parsed <code>Factory</code> isntances map.
      *
      * @return Map parsed <code>Factory</code> isntances map.
      */
     public Map getFactories() {
         return Collections.unmodifiableMap(factories);
     }
 
     /**
      * Returns parsed <code>CommandFactory</code> instance.
      *
      * @return CommandFactoryService parsed <code>CommandFactory</code> instance.
      */
     public CommandFactoryService getCommandFactory() {
         return commandFactory;
     }
 
     // Helper
     /**
      * Process &lt;init-param&gt; tag.
      *
      * @param atts Attributes tag attributes.
      */
     protected void processInitParamTag(Attributes atts) {
 
         String name = atts.getValue(NAME_ATTR);
         String value = atts.getValue(VALUE_ATTR);
 
         initParams.put(name, value);
 
     }
 
     /**
      * Process &lt;authenticator&gt; tag.
      *
      * @param atts Attributes tag attributes.
      * @throws SAXException if there is an error while processing tag.
      */
     protected void processAuthenticatorTag(Attributes atts) throws SAXException {
 
         String className = atts.getValue(CLASS_NAME_ATTR);
 
         try {
             BeanHelper bean = new BeanHelper(className);
             authc = (AuthenticatorService) bean.getInstance();
             bean.setProperties(authc, auxParams);
         }
         catch (Exception e) {
             throw new SAXException("Error in authenticathor " + className + " load", e);
         }
 
         auxParams.clear();
 
     }
 
     /**
      * Process &lt;authorizator&gt; tag.
      *
      * @param atts Attributes tag attributes.
      * @throws SAXException if there is an error while processing tag.
      */
     protected void processAuthorizatorTag(Attributes atts) throws SAXException {
 
         String className = atts.getValue(CLASS_NAME_ATTR);
 
         try {
             BeanHelper bean = new BeanHelper(className);
             authz = (AuthorizatorService) bean.getInstance();
             bean.setProperties(authz, auxParams);
         }
         catch (Exception e) {
             throw new SAXException("Error in authorizator " + className + " load", e);
         }
 
         auxParams.clear();
 
     }
 
     /**
      * Process &lt;log&gt; tag.
      *
      * @param atts Attributes tag attributes.
      * @throws SAXException if there is an error while processing tag.
      */
     protected void processLogTag(Attributes atts) throws SAXException {
 
         String className = atts.getValue(CLASS_NAME_ATTR);
         String logLvlStr = atts.getValue(LOG_LVL_ATTR);
 
         LoggerService logger = null;
         try {
             BeanHelper bean = new BeanHelper(className);
             logger = (LoggerService) bean.getInstance();
             bean.setProperties(logger, auxParams);
 
             if (logLvlStr.equals(DEBUG_VALUE)) {
                 logger.setLogLevel(Logger.DEBUG);
             }
             else if (logLvlStr.equals(INFO_VALUE)) {
                 logger.setLogLevel(Logger.INFO);
             }
             else if (logLvlStr.equals(WARNING_VALUE)) {
                 logger.setLogLevel(Logger.WARNING);
             }
             else if (logLvlStr.equals(ERROR_VALUE)) {
                 logger.setLogLevel(Logger.ERROR);
             }
             else if (logLvlStr.equals(PANIC_VALUE)) {
                 logger.setLogLevel(Logger.PANIC);
             }
 
         }
         catch (Exception e) {
             throw new SAXException("Error in logger " + className + " load", e);
         }
 
         loggers.add(logger);
 
         auxParams.clear();
 
     }
 
     /**
      * Process &lt;factory&gt; tag.
      *
      * @param atts Attributes tag attributes.
      * @throws SAXException if there is an error while processing tag.
      */
     protected void processFactoryTag(Attributes atts) throws SAXException {
 
         String name = atts.getValue(NAME_ATTR);
         String className = atts.getValue(CLASS_NAME_ATTR);
 
         FactoryService factory = null;
         try {
             BeanHelper bean = new BeanHelper(className);
             factory = (FactoryService) bean.getInstance();
             bean.setProperties(factory, auxParams);
         }
         catch (Exception e) {
             throw new SAXException("Error in factory " + className + " load", e);
         }
 
         factories.put(name, factory);
 
         auxParams.clear();
 
     }
 
     /**
      * Process &lt;command-factory&gt; tag.
      *
      * @param atts Attributes tag attributes.
      * @throws SAXException if there is an error while processing tag.
      */
     protected void processCommandFactoryTag(Attributes atts) throws SAXException {
 
         String className = atts.getValue(CLASS_NAME_ATTR);
         String preload = atts.getValue(PRELOAD_ATTR);
 
         try {
             BeanHelper bean = new BeanHelper(className);
             commandFactory = (CommandFactoryService) bean.getInstance();
             bean.setProperties(commandFactory, auxParams);
         }
         catch (Exception e) {
             throw new SAXException("Error in command factory " + className + " load", e);
         }
 
         auxParams.clear();
 
     }
 
     /**
      * Process &ltXXXX-param&gt; tags.
      *
      * @param atts Attributes tag attributes.
      */
     protected void processParamTag(Attributes atts) {
 
         String name = atts.getValue(NAME_ATTR);
         String value = atts.getValue(VALUE_ATTR);
 
         auxParams.put(name, value);
 
     }
 
 }