xml-dev - Re: SAX and Attribute value of type ENTITY ?

[David Megginson <david@megginson.com>]

Patrice Bonhomme writes:

 > Ok, so how can i get the corresponding ENTITY value within a SAX
 > application ?  And i think that the example i gave was not good
 > because the XML Rec says : "No External Entity References In
 > Attribute Values".
 > 
 > I said:
 > ] <?xml version="1.0" ?> <!DOCTYPE foo [ <!ELEMENT foo (#PCDATA)>
 > ] <!ATTLIST foo docref ENTITY #IMPLIED> <!ENTITY mydoc SYSTEM
 > ] 'mydoc.xml'> ]> <foo docref="mydoc">blah</foo>
 > 

 > If the Entity 'mydoc' was not an External entity (let's say a
 > simple internal entity, <!ENTITY mydoc 'mydoc.xml'>) what should
 > return the SAX driver ?  'mydoc' or 'mydoc.xml' ? Could i have
 > something like this : <!ENTITY mydoc SYSTEM 'mydoc.xml' NDATA xml>
 > ?

The last one is the only one that you're allowed to have -- ENTITY
attributes must contain the names of NDATA entities (no internal or
external text entities allowed).

SAX has a special handler called DTDHandler that will tell the
application about all declared NDATA entities and notations before
parsing the document element:

public interface DTDHandler
{
  public void notationDecl (String name, String publicId, 
                            String systemId);
  public void unparsedEntityDecl (String name, String publicId,
                                  String systemId, String notationName);
}

A common practice is to use these callbacks to build two hash tables
-- one for entities, and one for notations -- and then look up ENTITY
and NOTATION attributes in those tables when you are parsing within
the document element.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/

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