/*
 * Copyright (C) 2010 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.web.controller.router;

import org.exoplatform.web.controller.regexp.Literal;

/**
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
class PatternBuilder
{

   /** . */
   private final StringBuilder buffer = new StringBuilder();

   /** . */
   PatternBuilder()
   {
   }

   public PatternBuilder expr(CharSequence s)
   {
      if (s == null)
      {
         throw new NullPointerException("No null expression allowed");
      }
      buffer.append(s);
      return this;
   }

   public PatternBuilder expr(char s)
   {
      buffer.append(s);
      return this;
   }

   public PatternBuilder litteral(String s, int from, int to)
   {
      if (from < 0)
      {
         throw new IllegalArgumentException("No negative from argument");
      }
      if (to > s.length())
      {
         throw new IllegalArgumentException("No to argument greater than the string length");
      }
      if (from > to)
      {
         throw new IllegalArgumentException("The to argument cannot be greater than the from argument");
      }
      if (from < to)
      {
         for (int i = from;i < to;i++)
         {
            char c = s.charAt(i);
            if (Literal.isEscaped(c))
            {
               buffer.append('\\');
            }
            buffer.append(c);
         }
      }
      return this;
   }

   public PatternBuilder literal(String s, int from)
   {
      return litteral(s, from, s.length());
   }

   public PatternBuilder literal(String s)
   {
      return litteral(s, 0, s.length());
   }

   public PatternBuilder literal(char c)
   {
      return literal(Character.toString(c));
   }

   public String build()
   {
      return buffer.toString();
   }
}
