rdonkin     2003/04/02 11:04:30

  Added:       digester/src/java/org/apache/commons/digester
                        RegexRules.java
  Log:
  Added new Rule implementation based on a pluggable regex implementation. Also test 
case and a simple regex matching implementation
  
  Revision  Changes    Path
  1.1                  
jakarta-commons/digester/src/java/org/apache/commons/digester/RegexRules.java
  
  Index: RegexRules.java
  ===================================================================
  /*
   * $Header: 
/home/cvs/jakarta-commons/digester/src/java/org/apache/commons/digester/RegexRules.java,v
 1.1 2003/04/02 19:04:30 rdonkin Exp $
   * $Revision: 1.1 $
   * $Date: 2003/04/02 19:04:30 $
   *
   * ====================================================================
   *
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution, if
   *    any, must include the following acknowlegement:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowlegement may appear in the software itself,
   *    if and wherever such third-party acknowlegements normally appear.
   *
   * 4. The names "The Jakarta Project", "Commons", and "Apache Software
   *    Foundation" must not be used to endorse or promote products derived
   *    from this software without prior written permission. For written
   *    permission, please contact [EMAIL PROTECTED]
   *
   * 5. Products derived from this software may not be called "Apache"
   *    nor may "Apache" appear in their names without prior written
   *    permission of the Apache Group.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  
  package org.apache.commons.digester;
  
  import java.util.List;
  import java.util.Iterator;
  import java.util.ArrayList;
  
  /**
   * <p>Rules implementation that uses regular expression matching for paths.</p>
   *
   * <p>The regex implementation is pluggable, allowing different strategies to be 
used.
   * The basic way that this class work does not vary.
   * All patterns are tested to see if they match the path using the regex matcher.
   * All those that do are return in the order which the rules were added.</p>
   *
   * @author Robert Burrell Donkin
   * @version $Revision: 1.1 $ $Date: 2003/04/02 19:04:30 $
   */
  
  public class RegexRules extends AbstractRulesImpl {
  
      // --------------------------------------------------------- Fields
      
      /** All registered <code>Rule</code>'s  */
      private ArrayList registeredRules = new ArrayList();
      /** The regex strategy used by this RegexRules */
      private RegexMatcher matcher;
  
      // --------------------------------------------------------- Constructor
  
      /**
       * Construct sets the Regex matching strategy.
       *
       * @param matcher the regex strategy to be used, not null
       * @throws IllegalArgumentException if the strategy is null
       */
      public RegexRules(RegexMatcher matcher) {
          setRegexMatcher(matcher);
      }
  
      // --------------------------------------------------------- Properties
      
      /** 
       * Gets the current regex matching strategy.
       */
      public RegexMatcher getRegexMatcher() {
          return matcher;
      }
      
      /** 
       * Sets the current regex matching strategy.
       *
       * @param matcher use this RegexMatcher, not null
       * @throws IllegalArgumentException if the strategy is null
       */
      public void setRegexMatcher(RegexMatcher matcher) {
          if (matcher == null) {
              throw new IllegalArgumentException("RegexMatcher must not be null.");
          }
          this.matcher = matcher;
      } 
      
      // --------------------------------------------------------- Public Methods
  
      /**
       * Register a new Rule instance matching the specified pattern.
       *
       * @param pattern Nesting pattern to be matched for this Rule
       * @param rule Rule instance to be registered
       */
      protected void registerRule(String pattern, Rule rule) {
          registeredRules.add(new RegisteredRule(pattern, rule));
      }
  
      /**
       * Clear all existing Rule instance registrations.
       */
      public void clear() {
          registeredRules.clear();
      }
  
      /**
       * Finds matching rules by using current regex matching strategy.
       * The rule associated with each path that matches is added to the list of 
matches.
       * The order of matching rules is the same order that they were added.
       *
       * @param namespaceURI Namespace URI for which to select matching rules,
       *  or <code>null</code> to match regardless of namespace URI
       * @param pattern Nesting pattern to be matched
       * @return a list of matching <code>Rule</code>'s
       */
      public List match(String namespaceURI, String pattern) {
          //
          // not a particularly quick implementation
          // regex is probably going to be slower than string equality
          // so probably should have a set of strings
          // and test each only once
          //
          // XXX FIX ME - Time And Optimize
          //
          ArrayList rules = new ArrayList(registeredRules.size());
          Iterator it = registeredRules.iterator();
          while (it.hasNext()) {
              RegisteredRule next = (RegisteredRule) it.next();
              if (matcher.match(pattern, next.pattern)) {
                  rules.add(next.rule);
              }
          }
          return rules;
      }
  
  
      /**
       * Return a List of all registered Rule instances, or a zero-length List
       * if there are no registered Rule instances.  If more than one Rule
       * instance has been registered, they <strong>must</strong> be returned
       * in the order originally registered through the <code>add()</code>
       * method.
       */
      public List rules() {
          ArrayList rules = new ArrayList(registeredRules.size());
          Iterator it = registeredRules.iterator();
          while (it.hasNext()) {
              rules.add(((RegisteredRule) it.next()).rule);
          }
          return rules;
      }
      
      /** Used to associate rules with paths in the rules list */
      private class RegisteredRule {
          String pattern;
          Rule rule;
          
          RegisteredRule(String pattern, Rule rule) {
              this.pattern = pattern;
              this.rule = rule;
          }
      }
  }
  
  
  

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