XML parsers namespace support

Namespaces in XML messages are supported by the XMLNSC and XMLNS parsers. Namespaces are not supported by the XML parser.


The XMLNS and XMLNSC parsers can parse any well-formed XML document, whether or not the document contains namespaces. If elements or attributes have namespaces, those namespaces are applied to the elements and attributes in the message tree. Namespace prefix mappings are also carried in the message tree, and are used when serializing the message tree back to XML.

  • If an element or attribute in the input XML has a namespace, the corresponding node in the message tree also has that namespace.
  • If an element contains a namespace declaration (an xmlns attribute), a child element that contains its prefix and namespace URI is created in the message tree.

While the message is passing through a message flow, namespaces and namespace mappings can be modified using ESQL or any of the other transformation technologies that are offered by IBM® Integration Bus.


Namespaces and their prefixes are preserved in the message tree when parsing, and are used when the XMLNS and XMLNSC parsers convert a message tree to an XML bit stream.

  • When serializing a message tree, the parser scans for namespace declarations on each XML element. If any are found, it uses them to select the namespace prefixes in the output document.
  • If an element in the message tree has a namespace, but there is no in-scope namespace declaration for its namespace URI, a valid namespace prefix is automatically generated and used in the output XML. Auto-generated prefixes have the form NS1, NS2, and so on.
Tip: If an element in the message tree has a child element that is a ‘default namespace' declaration, every child of that element (whether an XML element or an XML attribute, at any nesting depth) must have a namespace. If this rule is not enforced, IBM Integration Bus cannot generate correct XML output for the message tree.