31.9. Variable Namespaces

Table 31.3, “XPath Variable Namespaces” shows the namespace URIs that are associated with the various namespace prefixes.

Table 31.3. XPath Variable Namespaces
Namespace URI	Prefix	Description
`http://camel.apache.org/schema/spring`	None	Default namespace (associated with variables that have no namespace prefix).
`http://camel.apache.org/xml/in/`	`in`	Used to reference header or body of the current exchange's In message.
`http://camel.apache.org/xml/out/`	`out`	Used to reference header or body of the current exchange's Out message.
`http://camel.apache.org/xml/functions/`	`functions`	Used to reference some custom functions.
`http://camel.apache.org/xml/variables/environment-variables`	`env`	Used to reference O/S environment variables.
`http://camel.apache.org/xml/variables/system-properties`	`system`	Used to reference Java system properties.
`http://camel.apache.org/xml/variables/exchange-property`	Undefined	Used to reference exchange properties. You must define your own prefix for this namespace.