11.11. XPath Domain-Specific Language

Note

You may find it convenient to undertake an XPath-based evaluation of XML-based messages. Red Hat supports this by shipping a domain-specific language implementation. Use this implementation to add XPath expressions to the rule file.
  1. First, define the expressions in the XPathLanguage.dsl file and use the following code to reference it in the rule set: 
    expander XPathLanguage.dsl
  2. The XPath Language makes sure the message is in JBOSS_XML and that the following items have been defined:
    1. xpathMatch<element> : this yields true if an element by this name is matched.
    2. xpathEquals<element> , <value> : this yields true if the element is found and its value equals the value.
    3. xpathGreaterThan<element> , <value> : this yields true if the element is found and its value is greater than the value.
    4. xpathLessThan<element> , <value> : this yields true if the element is found and its value is lower then the value.

    Note

    The fun_cbr quick-start demonstrates this use of XPath.

    Note

    It is possible to define a completely different domain-specific language.