XOM API for Processing XML with Java

["Steve Loughran" <steve.loughran AT gmail.com>]

Looking at the tail end of Element.addNamespaceDeclaration() I see this

       String currentBinding = getLocalNamespaceURI(prefix);
       if (currentBinding != null && !currentBinding.equals(uri)) {

           String message;
           if (prefix.equals("")) {
               message =  "Additional namespace " + uri
                 + " conflicts with existing default namespace "
                 + currentBinding;
           }
           else {
               message = "Additional namespace " + uri
                 + " for the prefix " + prefix
                 + " conflicts with existing namespace binding "
                 + currentBinding;
           }
           throw new NamespaceConflictException(message);
       }

       if (namespaces == null) namespaces = new Namespaces();
       namespaces.put(prefix, uri);

It seems to me that if currentbinding!=null &&
currentBinding.equals(uri), there's no need to bother with the put()
operation again.which saves on a few operations whose O() will be
relatively low order, but still somewhat gratuitous:

   void put(String prefix, String URI) {
       namespaces.put(prefix, URI);
       prefixes.remove(prefix);
       prefixes.add(prefix);
   }

Is the assumtion here that because getLocalNamespaceURI(prefix); also
scans the attributes for xmlns declarations, the act of adding the
namespace moves the prefix,namespace declaration into the hash table,
so speeding up later operations?

Steve