Working XML: Link management and preparing the future

        
package org.ananas.xm;
import java.io.*;
import java.net.*;
import java.util.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
import org.xml.sax.ext.LexicalHandler;
import org.ananas.util.NotImplementedException;
public class LinkFilter
   extends XMLFilterImpl
   implements LexicalHandler
{
   protected Messenger messenger;
   protected MoversSupervisor supervisor;
   protected String rootPrefix = null;
   protected File directory;
   protected LexicalHandler lexicalHandler = null;
   protected static final String lexicalHandlerProperty = "http://xml.org/sax/properties/lexical-handler";
   public LinkFilter(Messenger messenger,MoversSupervisor supervisor)
   {
      this.messenger = messenger;
      this.supervisor = supervisor;
   }
   public void setDirectory(File directory,int depth)
   {
      this.directory = directory;
      StringBuffer prefix = new StringBuffer();
      for(int i = 0;i < depth;i++)
         prefix.append("../");
      rootPrefix = prefix.toString();
   }
   public void startElement(String namespaceURI,
                            String lName,
                            String qName,
                            Attributes attributes)
      throws SAXException
   {
      try
      {
         int index = -1;
         if(qName.equals("a"))
            index = attributes.getIndex("href");
         else if(qName.equals("img") || qName.equals("input"))
            index = attributes.getIndex("src");
         if(index != -1)
         {
            String link = attributes.getValue(index);
            if(link.startsWith("!"))
               link = rootPrefix + link.substring(1);
            File linkFile = null;
            linkFile = new File(directory,link);
            if(linkFile.exists())
            {
               String outFile = supervisor.getMover(linkFile).getTargetName(linkFile);
               int pos = link.lastIndexOf('/');
               if(pos != -1)
                  link = link.substring(0,pos + 1) + outFile;
               else
                  link = outFile;
            }
            else if(!(link.startsWith("http:") || link.startsWith("ftp:") ||
                      link.startsWith("mailto:") || link.startsWith("news:")))
               messenger.warning(new XMException(Resources.getString("suspiciouslink"),new Object[] { link }));
            if(attributes instanceof AttributesImpl)
               ((AttributesImpl)attributes).setValue(index,link);
            else
               throw new NotImplementedException("only works for AttributeListImpl so far");
         }
      }
      catch(XMException e)
      {
         throw new SAXException(e);
      }
      super.startElement(namespaceURI,lName,qName,attributes);
   }
   public void setProperty(String name,Object value)
      throws SAXNotRecognizedException, SAXNotSupportedException
   {
      if(name.equals(lexicalHandlerProperty) &&
         value instanceof LexicalHandler)
         this.lexicalHandler = (LexicalHandler)lexicalHandler;
      else
         super.setProperty(name,value);
   }
   public Object getProperty(String name)
      throws SAXNotRecognizedException, SAXNotSupportedException
   {
      if(name.equals(lexicalHandlerProperty))
         return lexicalHandler;
      else
         return super.getProperty(name);
   }
   public void comment(char[] ch,int start,int length)
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.comment(ch,start,length);
   }
   public void endCDATA()
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.endCDATA();
   }
   public void endDTD()
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.endDTD();
   }
   public void endEntity(String name)
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.endEntity(name);
   }
   public void startCDATA()
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.startCDATA();
   }
   public void startDTD(String name,String publicId,String systemId)
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.startDTD(name,publicId,systemId);
   }
   public void startEntity(String name)
      throws SAXException
   {
      if(lexicalHandler != null)
         lexicalHandler.startEntity(name);
   }
}