Specified vs. Defaulted Attributes

• Infoset includes a flag saying whether a given attribute value was specified in the instance document or defaulted from the DTD.

• DOM also wants to know this

• Solution:

  package org.xml.sax.ext;
  
  public interface Attributes2 extends Attributes {
  
    public boolean isSpecified (int index);
    public boolean isSpecified (String uri, String localName);
    public boolean isSpecified (String qualifiedName);
    
    public boolean isDeclared (int index);
    public boolean isDeclared (String uri, String localName);
    public boolean isDeclared (String qualifiedName);
    
  }

• The isDeclared methods return false unless the attribute was declared in the DTD.

• This interface would be implemented by SAX 2.1 Attributes objects provided in startElement() callbacks

• The read-only http://xml.org/sax/features/use-attributes2 feature specifies whether Attributes2 is available