XML wire format: Handling xsi:type attributes

The prefix "xsi" is the namespace prefix used by convention for the XML Schema namespace for instances. XML documents can contain elements that have an xsi:type attribute. This provides an explicit data type for the element.

The MRM XML parser in sensitive to xsi:type attributes in the XML document. It modifies the data type of the element accordingly and adds the xsi:type attribute into the message tree.

The MRM XML writer is sensitive to xsi:type attributes in the message tree. It outputs xsi:type attributes according to XML Wire Format message set property Output policy for xsi:type attributes. For example, xsi:type attributes can be removed, output on all elements or output according to rules specified in the SOAP standard.

If validation is enabled for a WebSphere Message Broker message flow, the validation logic is sensitive to xsi:type attributes and uses them to modify the validation of the element. It will also validate the values of xsi:type attributes using the rules described in XML Schema Part 1: Structures on the World Wide Web Consortium (W3C) Web site.

There are several important points to remember when parsing and writing XML documents that contain xsi:type attributes.

For more information about xsi:type attributes, see XML Schema Part 0: Primer on the World Wide Web Consortium (W3C) Web site.

Related concepts
XML Schema and the message model
Related reference
XML Wire Format message set properties
Message flow migration notes