Parameter entities in the internal subset using DOM

László Bartos Mon, 21 Nov 2005 03:53:56 -0800

Hi,
 
I have already posted this question earlier, but without success:
 
I have a problem using xerces-2_7_1: I have to print out the internal subset of 
XML documents, but the parameter entity refs are always resolved by DOM parser. 
If I set the feature http://xml.org/sax/features/external-parameter-entities to 
false, then it is resolved to empty string (so the parameter entity ref 
disappears).
 
To reproduce the problem:
 
1. Save this as an XML document  
 
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE PEtest PUBLIC "-//TEST//DTD PETest XML//EN" "petest.dtd" [ <!ENTITY % 
local.ent PUBLIC "-//TEST//DTD PETest Extension XML//EN" ""> %local.ent; ]> 
<PETest> <front> </front> <body> </body></PETest>
 
2. Set the feature http://xml.org/sax/features/external-parameter-entities to 
false  and call the DOM parser. Here is a sample program:
public static void main(String argv[]) {
        ParserWrapper parser = null;
        // create parser
        try {
            parser = 
(ParserWrapper)Class.forName("dom.wrappers.Xerces").newInstance();
            parser.setFeature("http://xml.org/sax/features/namespaces";, false);
            parser.setFeature("http://xml.org/sax/features/validation";, false);
            
parser.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd";,
 false);
            
parser.setFeature("http://apache.org/xml/features/validation/schema";, false);
            
parser.setFeature("http://apache.org/xml/features/validation/dynamic";, false);
            parser.setFeature("http://apache.org/xml/features/xinclude";, false);
            
parser.setFeature("http://xml.org/sax/features/external-parameter-entities";, 
false);
            // parse file
            Document document = parser.parse(argv[0]);
            System.out.println(document.getDoctype().getInternalSubset());
        }
        catch (Exception e) {
          e.printStackTrace(System.err);
        }
    } // main(String[])


Result: The getInternalSubset will return 
<!ENTITY % local.ent PUBLIC "-//TEST//DTD PETest Extension XML//EN" "">
which means that the entity ref is resolved to empty string. (If I set 
http://xml.org/sax/features/external-parameter-entities to true, then the 
parameter entity ref is correctly resolved and returned in getInternalSubset, 
however I need the reference without resolving it.)  

I have found that if I add the following code into 
org.apache.xerces.parsers.AbstractDOMParser.startParameterEntity(String, 
XMLResourceIdentifier, String, Augmentations): 

   ...
   //append the paremeter entity reference if it was not resolved
        if (fInDTD && fInternalSubset != null && !fInDTDExternalSubset && augs 
!= null) {
          Object skip = augs.getItem(Constants.ENTITY_SKIPPED);
          if (skip instanceof Boolean && (Boolean)skip == Boolean.TRUE) { 
            fInternalSubset.append(name);
            fInternalSubset.append(";\n");
          }
        }
 
then the parameter entity ref is included in the internal subset. 
 
I'm far to say that I have experience using xerces, so it can happen, that I 
use the wrong functions. Can somebody confirm whether this is a bug or a 
feature?
 
Bartos László

<<winmail.dat>>

---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Parameter entities in the internal subset using DOM

Reply via email to