Camel supports XQuery to allow an Expression or Predicate to be used in the DSL or Xml Configuration. For example you could use XQuery to create an Predicate in a Message Filter or as an Expression for a Recipient List.
Camel 2.8.3/2.9: Whether to allow using StAX as the
You can also use functions inside your query, in which case you need an explicit type conversion (or you will get a org.w3c.dom.DOMException: HIERARCHY_REQUEST_ERR) by passing the Class as a second argument to the xquery() method.
The IN message body will be set as the
contextItem. Besides this these Variables is also added as parameters:
The current Exchange
The In message's body
The OUT message's body (if any)
You can access the value of exchange.in.headers with key foo by using the variable which name is in.headers.foo
You can access the value of exchange.out.headers with key foo by using the variable which name is out.headers.foo variable
Any exchange.properties and exchange.in.headers and any additional parameters set using
Using XML configuration
If you prefer to configure your routes in your Spring XML file then you can use XPath expressions as follows
Notice how we can reuse the namespace prefixes, foo in this case, in the XPath expression for easier namespace based XQuery expressions!
When you use functions in your XQuery expression you need an explicit type conversion which is done in the xml configuration via the @type attribute:
Using XQuery as transformation
We can do a message translation using transform or setBody in the route, as shown below:
Notice that xquery will use DOMResult by default, so if we want to grab the value of the person node, using text() we need to tell xquery to use String as result type, as shown:
Using XQuery as an endpoint
The following example shows how to take a message of an ActiveMQ queue (MyQueue) and transform it using XQuery and send it to MQSeries.
XQuery is a very powerful language for querying, searching, sorting and returning XML. For help learning XQuery try these tutorials
You might also find the XQuery function reference useful
Loading script from external resource
Available as of Camel 2.11
You can externalize the script and have Camel load it from a resource such as
This is done using the following syntax:
"resource:scheme:location", eg to refer to a file on the classpath you can do:
To use XQuery in your camel routes you need to add the a dependency on camel-saxon which implements the XQuery language.
If you use maven you could just add the following to your pom.xml, substituting the version number for the latest & greatest release (see the download page for the latest versions).