/****************************************************************
    * 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.james.jspf.impl;
  
  import org.apache.james.jspf.core.LogEnabled;
  import org.apache.james.jspf.core.Logger;
  import org.apache.james.jspf.core.exceptions.PermErrorException;
  import org.apache.james.jspf.parser.TermsFactory;
  import org.apache.james.jspf.terms.Configuration;
  import org.apache.james.jspf.terms.ConfigurationEnabled;
  import org.apache.james.jspf.wiring.WiringService;
  import org.apache.james.jspf.wiring.WiringServiceException;
  import org.apache.james.jspf.wiring.WiringServiceTable;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Properties;
  
  /**
   * The default implementation of the TermsFactory
   */
  public class DefaultTermsFactory implements TermsFactory {
      
      private String termFile = "org/apache/james/jspf/parser/jspf.default.terms";
      
      private Collection mechanismsCollection;
  
      private Collection modifiersCollection;
  
      private Logger log;
      
      private WiringService wiringService;
  
      public DefaultTermsFactory(Logger log) {
          this.log = log;
          this.wiringService = new WiringServiceTable();
          ((WiringServiceTable) this.wiringService).put(LogEnabled.class, log);
          init();
      }
  
      public DefaultTermsFactory(Logger log, WiringService wiringService) {
          this.log = log;
          this.wiringService = wiringService;
          init();
      }
  
      /**
       * Initialize the factory and the services
       */
      private void init() {
          try {
              InputStream is = Thread.currentThread().getContextClassLoader()
                      .getResourceAsStream(termFile);
              if (is == null) {
                  throw new NullPointerException("Unable to find the "+termFile+" resource in the classpath");
              }
              Properties p = new Properties();
              p.load(is);
              String mechs = p.getProperty("mechanisms");
              String mods = p.getProperty("modifiers");
              String[] classes;
              classes = mechs.split(",");
              Class[] knownMechanisms = new Class[classes.length];
              for (int i = 0; i < classes.length; i++) {
                  log.debug("Add following class as known mechanismn: "
                          + classes[i]);
                  knownMechanisms[i] = Thread.currentThread()
                          .getContextClassLoader().loadClass(classes[i]);
              }
              mechanismsCollection = createTermDefinitionCollection(knownMechanisms);
              classes = mods.split(",");
              Class[] knownModifiers = new Class[classes.length];
              for (int i = 0; i < classes.length; i++) {
                  log.debug("Add following class as known modifier: "
                          + classes[i]);
                  knownModifiers[i] = Thread.currentThread()
                          .getContextClassLoader().loadClass(classes[i]);
              }
              modifiersCollection = createTermDefinitionCollection(knownModifiers);
     
         } catch (IOException e) {
             throw new IllegalStateException(
                     "Term configuration cannot be found");
         } catch (ClassNotFoundException e) {
             throw new IllegalStateException(
                     "One configured class cannot be found");
         }
     }
 
 
     /**
      * Create a collection of term definitions supported by this factory.
      * 
      * @param classes
      *            classes to analyze
      * @param staticFieldName
      *            static field to concatenate
      * @return map <Class,Pattern>
      */
     private Collection createTermDefinitionCollection(Class[] classes) {
         Collection l = new ArrayList();
         for (int j = 0; j < classes.length; j++) {
             try {
                 l.add(new DefaultTermDefinition(classes[j]));
             } catch (Exception e) {
                 log.debug("Unable to create the term collection", e);
                 throw new IllegalStateException(
                         "Unable to create the term collection");
             }
         }
         return Collections.synchronizedCollection(l);
     }
 
 
     /**
      * @see org.apache.james.jspf.parser.TermsFactory#createTerm(java.lang.Class, org.apache.james.jspf.terms.Configuration)
      */
     public Object createTerm(Class termDef, Configuration subres) throws PermErrorException, InstantiationException {
         try {
             Object term = termDef.newInstance();
             
             try {
                 wiringService.wire(term);
             } catch (WiringServiceException e) {
                 throw new InstantiationException(
                         "Unexpected error adding dependencies to term: " + e.getMessage());
             }
 
             if (term instanceof ConfigurationEnabled) {
                 if (subres == null || subres.groupCount() == 0) {
                     ((ConfigurationEnabled) term).config(null);
                 } else {
                     ((ConfigurationEnabled) term).config(subres);
                 }
             }
             return term;
         } catch (IllegalAccessException e) {
             throw new InstantiationException(
                     "Unexpected error creating term: " + e.getMessage());
         }
     }
 
 
     /**
      * @see org.apache.james.jspf.parser.TermsFactory#getMechanismsCollection()
      */
     public Collection getMechanismsCollection() {
         return mechanismsCollection;
     }
 
 
     /**
      * @see org.apache.james.jspf.parser.TermsFactory#getModifiersCollection()
      */
     public Collection getModifiersCollection() {
         return modifiersCollection;
     }
 
 }