1   /**
    2    * Licensed under the Artistic License; you may not use this file
    3    * except in compliance with the License.
    4    * You may obtain a copy of the License at
    5    *
    6    *      http://displaytag.sourceforge.net/license.html
    7    *
    8    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
    9    * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
   10    * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
   11    */
   12   package org.displaytag.decorator;
   13   
   14   import javax.servlet.jsp.PageContext;
   15   
   16   import org.apache.commons.lang.ArrayUtils;
   17   import org.apache.commons.lang.StringUtils;
   18   import org.displaytag.properties.MediaTypeEnum;
   19   import org.displaytag.util.TagConstants;
   20   
   21   
   22   /**
   23    * This takes the string that is passed in, and "auto-links" it, it turns email addresses into hyperlinks, and also
   24    * turns things that looks like URLs into hyperlinks as well.
   25    * @author Fabrizio Giustina
   26    * @version $Revision: 1081 $ ($Author: fgiust $)
   27    */
   28   public class AutolinkColumnDecorator implements DisplaytagColumnDecorator
   29   {
   30   
   31       /**
   32        * Instance used for the "autolink" tag attribute.
   33        */
   34       public static final DisplaytagColumnDecorator INSTANCE = new AutolinkColumnDecorator();
   35   
   36       /**
   37        * "://".
   38        */
   39       private static final String URL_DELIM = "://"; //$NON-NLS-1$
   40   
   41       /**
   42        * Urls.
   43        */
   44       private static final String[] URLS_PREFIXES = //
   45       new String[]{"http", "https", "ftp"}; //$NON-NLS-1$ //$NON-NLS-1$ //$NON-NLS-1$
   46   
   47       /**
   48        * @see org.displaytag.decorator.DisplaytagColumnDecorator#decorate(Object, PageContext, MediaTypeEnum)
   49        */
   50       public Object decorate(Object columnValue, PageContext pageContext, MediaTypeEnum media)
   51       {
   52   
   53           if (columnValue == null)
   54           {
   55               return null;
   56           }
   57           String work = columnValue.toString();
   58   
   59           int urlBegin;
   60           StringBuffer buffer = new StringBuffer();
   61   
   62           // First check for email addresses.
   63           while ((urlBegin = work.indexOf('@')) != -1)
   64           {
   65               int start = 0;
   66               int end = work.length() - 1;
   67   
   68               // scan backwards...
   69               for (int j = urlBegin; j >= 0; j--)
   70               {
   71                   if (Character.isWhitespace(work.charAt(j)))
   72                   {
   73                       start = j + 1;
   74                       break;
   75                   }
   76               }
   77   
   78               // scan forwards...
   79               for (int j = urlBegin; j <= end; j++)
   80               {
   81                   if (Character.isWhitespace(work.charAt(j)))
   82                   {
   83                       end = j - 1;
   84                       break;
   85                   }
   86               }
   87   
   88               String email = work.substring(start, end + 1);
   89   
   90               buffer.append(work.substring(0, start)).append("<a href=\"mailto:") //$NON-NLS-1$
   91                   .append(email + "\">") //$NON-NLS-1$
   92                   .append(email).append("</a>"); //$NON-NLS-1$
   93   
   94               if (end == work.length())
   95               {
   96                   work = TagConstants.EMPTY_STRING;
   97               }
   98               else
   99               {
  100                   work = work.substring(end + 1);
  101               }
  102           }
  103   
  104           work = buffer.toString() + work;
  105           buffer = new StringBuffer();
  106   
  107           // Now check for urls...
  108           while ((urlBegin = work.indexOf(URL_DELIM)) != -1)
  109           {
  110   
  111               // scan backwards...
  112               int fullUrlBegin = urlBegin;
  113               StringBuffer prefixBuffer = new StringBuffer(10);
  114               for (int j = fullUrlBegin - 1; j >= 0; j--)
  115               {
  116                   if (Character.isWhitespace(work.charAt(j)))
  117                   {
  118                       fullUrlBegin = j + 1;
  119                       break;
  120                   }
  121                   fullUrlBegin = j;
  122                   prefixBuffer.append(work.charAt(j));
  123               }
  124   
  125               if (!ArrayUtils.contains(URLS_PREFIXES, StringUtils.reverse(prefixBuffer.toString())))
  126               {
  127   
  128                   buffer.append(work.substring(0, urlBegin + 3));
  129                   work = work.substring(urlBegin + 3);
  130                   continue;
  131               }
  132   
  133               int urlEnd = work.length();
  134   
  135               // scan forwards...
  136               for (int j = urlBegin; j < urlEnd; j++)
  137               {
  138                   if (Character.isWhitespace(work.charAt(j)))
  139                   {
  140                       urlEnd = j;
  141                       break;
  142                   }
  143               }
  144   
  145               String url = work.substring(fullUrlBegin, urlEnd);
  146   
  147               buffer.append(work.substring(0, fullUrlBegin)).append("<a href=\"")//$NON-NLS-1$
  148                   .append(url).append("\">")//$NON-NLS-1$
  149                   .append(url).append("</a>"); //$NON-NLS-1$
  150   
  151               if (urlEnd >= work.length())
  152               {
  153                   work = TagConstants.EMPTY_STRING;
  154               }
  155               else
  156               {
  157                   work = work.substring(urlEnd);
  158               }
  159           }
  160   
  161           buffer.append(work);
  162           return buffer.toString();
  163       }
  164   
  165   }