code: public void externalEntityDecl(
          String name,
          String publicId,
          String systemId)
          throws SAXException
      {
          try {
              DTDprolog();
              
              m_writer.write("<!ENTITY ");            
              m_writer.write(name);
              if (publicId != null) {
                  m_writer.write(" PUBLIC \"");
                  m_writer.write(publicId);
    
              }
              else {
                  m_writer.write(" SYSTEM \"");
                  m_writer.write(systemId);
              }
              m_writer.write("\" >");
              m_writer.write(m_lineSep, 0, m_lineSepLen);
          } catch (IOException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }
  
      }
docs: Report a parsed external entity declaration.
  
  <p>Only the effective (first) declaration for each entity
  will be reported.</p>
  
  @param name The name of the entity.  If it is a parameter
  entity, the name will begin with '%'.
  @param publicId The declared public identifier of the entity, or
  null if none was declared.
  @param systemId The declared system identifier of the entity.
  @exception SAXException The application may raise an exception.
  @see #internalEntityDecl
  @see org.xml.sax.DTDHandler#unparsedEntityDecl