package org.apache.maven.doxia.module.twiki.parser;

 /*

  * 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.

  */

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import org.apache.maven.doxia.util.ByLineSource;

 import org.apache.maven.doxia.parser.ParseException;

 /**

  * Block that represents an horizontal rule

  *

  * @author Juan F. Codagnone

  * @version $Id: HRuleBlockParser.java 746991 2009-02-23 12:35:46Z vsiveton $

  */

 public class HRuleBlockParser

     implements BlockParser

 {

     /**

      * pattern used to detect horizontal rulers

      */

     private static final Pattern HRULE_PATTERN = Pattern.compile( "^(---)(-*)(.*)$" );

     /** {@inheritDoc} */

     public final boolean accept( final String line )

     {

         final Matcher m = HRULE_PATTERN.matcher( line );

         boolean ret = false;

         if ( m.lookingAt() )

         {

             final int textGroup = 3;

             String s = m.group( textGroup );

             if ( s != null && !s.startsWith( "+" ) )

             {

                 ret = true;

             }

         }

         return ret;

     }

     /**

      * {@inheritDoc}

      */

     public final Block visit( final String line, final ByLineSource source )

         throws ParseException

     {

         Block ret = new HorizontalRuleBlock();

         final Matcher matcher = HRULE_PATTERN.matcher( line );

         if ( matcher.lookingAt() )

         {

             final int textGroup = 3;

             source.unget( matcher.group( textGroup ) );

         }

         else

         {

             throw new ParseException( "i was expecting a hruler!" );

         }

         return ret;

     }

 }