Unicode Characters Supported in XML 1.1 Names

XML Tutorials - Herong's Tutorial Examples

∟Unicode Characters Supported in XML 1.1 Names

This section provides a tutorial example showing that Unicode characters from higher versions are allowed in XML 1.1 names.

XML 1.1 also allows more Unicode characters to be used in XML element names or attribute names. Since end-of-line characters are not easy to be presented as text files, I created this test program, EndOfLineXml.java:

/* UnicodeNameXml.java
 * Copyright (c) 2002-2018 HerongYang.com. All Rights Reserved.
 */
import java.io.*;
import java.math.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
class UnicodeNameXml {
   public static void main(String[] args) {
      try {
         String ver = args[0];
         String xmlString =
            "<?xml version=\""+ver+"\" encoding=\"UTF-16BE\"?><code>"
            +"<u0180\u0180>\u0180 - v1.1.0</u0180\u0180>"
            +"<u20AB\u20AB>\u20AB - v2.0.0</u20AB\u20AB>"
            +"<u0233\u0233>\u0233 - v3.0.0</u0233\u0233>"
            +"<u0236\u0236>\u0236 - v4.0.0</u0236\u0236>"
            +"<u0237\u0237>\u0237 - v4.1.0</u0237\u0237>"
            +"</code>";
         File xmlFile = new File(args[1]);
         FileOutputStream fos = new FileOutputStream(xmlFile);
         OutputStreamWriter osw =
            new OutputStreamWriter(fos,"UTF-16BE");
         osw.write(xmlString);
         osw.close();

         DocumentBuilderFactory fct
            = DocumentBuilderFactory.newInstance();
         DocumentBuilder bld = fct.newDocumentBuilder();
         Document doc = bld.parse(xmlFile);
         dumpNode(doc, "");

      } catch (Exception e) {
         System.out.println(e.toString());
      }
   }
   static void dumpNode(Node n, String p) throws Exception {
      NodeList l = n.getChildNodes();
      NamedNodeMap m = n.getAttributes();
      int ml = -1;
      if (m!=null) ml = m.getLength();
      System.out.println(p+n.getNodeName()+": "
         +n.getNodeType()+", "+l.getLength()+", "
         +ml+", "+n.getNodeValue());
      for (int i=0; i<ml; i++) {
         Node c = m.item(i);
         dumpNode(c,p+" |-");
      }
      for (int i=0; i<l.getLength(); i++) {
         Node c = l.item(i);
         dumpNode(c,p+" ");
      }
   }
}

Some notes on UnicodeNameXml.java:

The XML document is created inside the program as a String object, instead of loaded from an input file.
The XML document has 5 elements with names using characters from different Unicode versions.

Let's try XML 1.0 first with JDK:

herong> java UnicodeNameXml 1.0 unicode-name-1-0.xml

[Fatal Error] unicode-name-1-0.xml:1:81: Element type "u20AB" must be
followed by either attribute specifications, ">" or "/>".
org.xml.sax.SAXParseException; systemId:
file:/C:/herong/unicode-name-1-0.xml;
lineNumber: 1; columnNumber: 81; Element type "u20AB" must be followed
by either attribute specifications, ">" or "/>".

The output proves that Unicode 1.1.0 character #x0180 is allowed in XML 1.0 names. But Unicode 2.0.0 character #x20AB is not allowed. Other Unicode characters included in the test program are not allowed. You remove the #x20AB line to test them.

Here is the output of XML 1.1:

herong> java UnicodeNameXml 1.1 unicode-name-1-1.xml

#document: 9, 1, -1, null
 code: 1, 5, 0, null
  u0180?: 1, 1, 0, null
   #text: 3, 0, -1, ? - v1.1.0
  u20AB?: 1, 1, 0, null
   #text: 3, 0, -1, ? - v2.0.0
  u0233?: 1, 1, 0, null
   #text: 3, 0, -1, ? - v3.0.0
  u0236?: 1, 1, 0, null
   #text: 3, 0, -1, ? - v4.0.0
  u0237?: 1, 1, 0, null
   #text: 3, 0, -1, ? - v4.1.0