/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
    *
    * Licensed 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.acegisecurity.intercept.web;
  
  import org.acegisecurity.ConfigAttributeDefinition;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.oro.text.regex.MalformedPatternException;
  import org.apache.oro.text.regex.Pattern;
  import org.apache.oro.text.regex.PatternMatcher;
  import org.apache.oro.text.regex.Perl5Compiler;
  import org.apache.oro.text.regex.Perl5Matcher;
  
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  import java.util.Vector;
  
  
  /**
   * Maintains a <code>List</code> of <code>ConfigAttributeDefinition</code>s associated with different HTTP request
   * URL regular expression patterns.<p>Regular expressions are used to match a HTTP request URL against a
   * <code>ConfigAttributeDefinition</code>.</p>
   *  <p>The order of registering the regular expressions using the {@link #addSecureUrl(String,
   * ConfigAttributeDefinition)} is very important. The system will identify the <b>first</b>  matching regular
   * expression for a given HTTP URL. It will not proceed to evaluate later regular expressions if a match has already
   * been found. Accordingly, the most specific regular expressions should be registered first, with the most general
   * regular expressions registered last.</p>
   *  <p>If no registered regular expressions match the HTTP URL, <code>null</code> is returned.</p>
   */
  public class RegExpBasedFilterInvocationDefinitionMap extends AbstractFilterInvocationDefinitionSource
      implements FilterInvocationDefinition {
      //~ Static fields/initializers =====================================================================================
  
      private static final Log logger = LogFactory.getLog(RegExpBasedFilterInvocationDefinitionMap.class);
  
      //~ Instance fields ================================================================================================
  
      private List requestMap = new Vector();
      private boolean convertUrlToLowercaseBeforeComparison = false;
  
      //~ Methods ========================================================================================================
  
      public void addSecureUrl(String perl5RegExp, ConfigAttributeDefinition attr) {
          Pattern compiledPattern;
          Perl5Compiler compiler = new Perl5Compiler();
  
          try {
              compiledPattern = compiler.compile(perl5RegExp, Perl5Compiler.READ_ONLY_MASK);
          } catch (MalformedPatternException mpe) {
              throw new IllegalArgumentException("Malformed regular expression: " + perl5RegExp);
          }
  
          requestMap.add(new EntryHolder(compiledPattern, attr));
  
          if (logger.isDebugEnabled()) {
              logger.debug("Added regular expression: " + compiledPattern.getPattern().toString() + "; attributes: "
                  + attr);
          }
      }
  
      public Iterator getConfigAttributeDefinitions() {
          Set set = new HashSet();
          Iterator iter = requestMap.iterator();
  
          while (iter.hasNext()) {
              EntryHolder entryHolder = (EntryHolder) iter.next();
              set.add(entryHolder.getConfigAttributeDefinition());
          }
  
          return set.iterator();
      }
  
      public int getMapSize() {
          return this.requestMap.size();
      }
  
      public boolean isConvertUrlToLowercaseBeforeComparison() {
          return convertUrlToLowercaseBeforeComparison;
      }
  
      public ConfigAttributeDefinition lookupAttributes(String url) {
          PatternMatcher matcher = new Perl5Matcher();
 
         Iterator iter = requestMap.iterator();
 
         if (isConvertUrlToLowercaseBeforeComparison()) {
             url = url.toLowerCase();
 
             if (logger.isDebugEnabled()) {
                 logger.debug("Converted URL to lowercase, from: '" + url + "'; to: '" + url + "'");
             }
         }
 
         while (iter.hasNext()) {
             EntryHolder entryHolder = (EntryHolder) iter.next();
 
             boolean matched = matcher.matches(url, entryHolder.getCompiledPattern());
 
             if (logger.isDebugEnabled()) {
                 logger.debug("Candidate is: '" + url + "'; pattern is " + entryHolder.getCompiledPattern().getPattern()
                     + "; matched=" + matched);
             }
 
             if (matched) {
                 return entryHolder.getConfigAttributeDefinition();
             }
         }
 
         return null;
     }
 
     public void setConvertUrlToLowercaseBeforeComparison(boolean convertUrlToLowercaseBeforeComparison) {
         this.convertUrlToLowercaseBeforeComparison = convertUrlToLowercaseBeforeComparison;
     }
 
     //~ Inner Classes ==================================================================================================
 
     protected class EntryHolder {
         private ConfigAttributeDefinition configAttributeDefinition;
         private Pattern compiledPattern;
 
         public EntryHolder(Pattern compiledPattern, ConfigAttributeDefinition attr) {
             this.compiledPattern = compiledPattern;
             this.configAttributeDefinition = attr;
         }
 
         protected EntryHolder() {
             throw new IllegalArgumentException("Cannot use default constructor");
         }
 
         public Pattern getCompiledPattern() {
             return compiledPattern;
         }
 
         public ConfigAttributeDefinition getConfigAttributeDefinition() {
             return configAttributeDefinition;
         }
     }
 }