Control Codes Supported in XML 1.1

XML Tutorials - Herong's Tutorial Examples

∟Control Codes Supported in XML 1.1

This section provides a tutorial example showing that more control codes are supported in XML 1.1 as character references.

First, let's verify that XML 1.1 allows us to use control characters i n #x01 to #x1F and #x7F to #x9F ranges as character references. Here is my example XML 1.0 file, control-codes-1-0.xml, with some control codes:

<?xml version="1.0"?>
<pre>
SOH: (#x01;)=(&#x01;)
STX: (#x02;)=(&#x02;)
ETX: (#x03;)=(&#x03;)
EOT: (#x04;)=(&#x04;)
ENQ: (#x05;)=(&#x05;)
ACK: (#x06;)=(&#x06;)
BEL: (#x07;)=(&#x07;)
BS: (#x08;)=(&#x08;)
HT: (#x09;)=(&#x09;)
LF: (#x0A;)=(&#x0A;)
VT: (#x0B;)=(&#x0B;)
FF: (#x0C;)=(&#x0C;)
CR: (#x0D;)=(&#x0D;)
SO: (#x0E;)=(&#x0E;)
SI: (#x0F;)=(&#x0F;)
</pre>

Try to parse it with DOMBrowser.java. You should some errors:

herong> java DOMBrowser control-codes-1-0.xml

[Fatal Error] control-codes-1-0.xml:3:26: Character reference "&#
org.xml.sax.SAXParseException; systemId:
file:/C:/herong/control-codes-1-0.xml; lineNumber: 3; columnNumber: 21;
Character reference "&#

Okay. The output proves that XML 1.0 does not support some control codes listed in the XML file. If you read the error message carefully, you will that the first error occurred at line 3 and column 21, which is the control code STX (#x02). So the control code SOH (#x01) is supported in XML 1.0, but STX (#x02) is not.

Now let's put those control codes in an XML 1.1 file, control-codes-1-1.xml:

<?xml version="1.1"?>
<pre>
SOH: (#x01;)=(&#x01;)
STX: (#x02;)=(&#x02;)
ETX: (#x03;)=(&#x03;)
EOT: (#x04;)=(&#x04;)
ENQ: (#x05;)=(&#x05;)
ACK: (#x06;)=(&#x06;)
BEL: (#x07;)=(&#x07;)
BS: (#x08;)=(&#x08;)
HT: (#x09;)=(&#x09;)
LF: (#x0A;)=(&#x0A;)
VT: (#x0B;)=(&#x0B;)
FF: (#x0C;)=(&#x0C;)
CR: (#x0D;)=(&#x0D;)
SO: (#x0E;)=(&#x0E;)
SI: (#x0F;)=(&#x0F;)
</pre>

Run the same test with the XML 1.1 file:

herong> java DOMBrowser control-codes-1-0.xml

#document: 9, 1, -1, null
 pre: 1, 1, 0, null
  #text: 3, 0, -1, 02;H: (#x01;)=(?)
STX: (#x02;)=(?)
ETX: (#x03;)=(?)
EOT: (#x04;)=(?)
ENQ: (#x05;)=(?)
ACK: (#x06;)=(?)
BEL: (#x07;)=()
BS: (#x08;)=)
HT: (#x09;)=(   )
LF: (#x0A;)=(
)
VT: (#x0B;)=(?)
FF: (#x0C;)=(?)
)R: (#x0D;)=(
SO: (#x0E;)=(?)
SI: (#x0F;)=(?)