Entity Manager

[Armin Pfarr <ap...@vipsurf.de>]

I'd like to associate an Entity-manager with Xerces and fail to get it
right. The classes are quite straightforward

public em extends EntityManager {

	public InputStream(String pubid, String sysid) {
		if(pubid.equals("foo"))
			return new InputStream("file:/c:/dtd/dtd1.dtd");
		else
			return null;
	}
}

Then I attach this manager to a parser using

	parser.setEntityManager(new em());

The parser does not use the manager as expected. Any idea?

Armin

AW: Entity Manager

[Armin Pfarr <ap...@vipsurf.de>]

Sorry for posting this invalid fragment. I have a complete "program" that
looks like

package examples;

import java.io.*;
import org.xml.sax.*;
import org.apache.xerces.parsers.*;

class Resolver implements EntityResolver {

   public InputSource resolveEntity(String pubId, String sysId)
	throws IOException, SAXException {
      if(pubId != null) {
         System.out.println("resolving entity "+ pubId+ " SYSTEM "+sysId);
         InputSource is = new InputSource("file:///c:/dtd/test.dtd");
         return is;
      } else
         return null;
   }
}

public class MyParser extends SAXParser {

   public MyParser() {
      setEntityResolver(new Resolver());
   }

   public static void main(String args[]) {
      MyParser parser = new MyParser();
      try {
         System.out.println("start parse");
         parser.parse(args[0]);
         System.out.println("end parse");
      } catch(org.xml.sax.SAXParseException e) {
         System.out.println("SaxParseException: "+e.getMessage());
         System.out.println(getLocationString(e));
      }
      catch (Exception e) {
         System.out.println(e.getMessage());
         e.printStackTrace(System.out);
      }
   }
   private static String getLocationString(SAXParseException ex) {
       StringBuffer str = new StringBuffer();

       String systemId = ex.getSystemId();
       if (systemId != null) {
           int index = systemId.lastIndexOf('/');
           if (index != -1)
               systemId = systemId.substring(index + 1);
           str.append(systemId);
       }
       str.append(':');
       str.append(ex.getLineNumber());
       str.append(':');
       str.append(ex.getColumnNumber());

       return str.toString();

   }
}

When running this program against an XML-file

<?xml version="1.0" ?>
<!DOCTYPE test PUBLIC "-//Private//Test DTD//EN" "doctypes/test.dtd">
<test>
	<title>hello</title>
</test>

I get the following output:
"
start parse
resolving entity -//Private//Test DTD//EN doctypes/test.dtd
SAXParseException: File "doctypes/test.dtd" not found.
test.xml:-1:-1
"
The entity resolver obviously gets called but still the parser tries to use
the System Identifier of the instance that points to a non-existing file
(that was intended!)

Armin

Re: Entity Manager

[Andy Clark <an...@apache.org>]

Armin,

There are a number of problems with your code. The immediate ones
that I see are:

1) It's an EntityResolver, not an EntityManager and it's an
   interface so you would "implement" it, not "extend" it.
2) The method is "resolveEntity" and it returns an "InputSource".
   I think that you mean to write "InputSource" everywhere that
   you write "InputStream".
3) The method also should declare that it throws IOException and
   SAXException.
4) "file:/c:/dtd/dtd1.dtd" is the wrong way to use the "file"
   protocol. Try "file:///c:/dtd/dtd1.dtd" instead.

Make the appropriate changes and let me know if it works for you.

-- 
Andy Clark * IBM, JTC - Silicon Valley * andyc@apache.org