LibraryToggle FramesPrintFeedback

The velocity: component allows you to process a message using an Apache Velocity template. This can be ideal when using Templating to generate responses for requests.

Option Default Description
loaderCache true Velocity based file loader cache.
contentCache New option in Apache Camel 1.4: Cache for the resource content when it is loaded. By default, it's false in Apache Camel 1.x. By default, it's true in Apache Camel 2.x.
encoding null New option in Apache Camel 1.6: Character encoding of the resource content.
propertiesFile null New option in Camel 2.1: The URI of the properties file which is used for VelocityEngine initialization.

The velocity component sets some headers on the message (you cannot set these yourself):

Header Description
org.apache.camel.velocity.resource Apache Camel 1.x: The resource as an org.springframework.core.io.Resource object.
org.apache.camel.velocity.resourceUri Apache Camel 1.x: The templateName as a String object.
CamelVelocityResource Apache Camel 2.0: The resource as an org.springframework.core.io.Resource object.
CamelVelocityResourceUri Apache Camel 2.0: The templateName as a String object.

In Apache Camel 1.4 headers set during the Velocity evaluation are returned to the message and added as headers. This makes it possible to return values from Velocity to the Message.

For example, to set the header value of fruit in the Velocity template .tm:

$in.setHeader('fruit', 'Apple')

The fruit header is now accessible from the message.out.headers.

Apache Camel will provide exchange information in the Velocity context (just a Map). The Exchange is transfered as:

key value
exchange The Exchange itself.
headers The headers of the In message.
camelContext The Camel Context intance.
request The In message.
in The In message.
body The In message body.
out The Out message (only for InOut message exchange pattern).
response The Out message (only for InOut message exchange pattern).

Available as of Camel 2.1 Camel provides two headers by which you can define a different resource location for a template or the template content itself. If any of these headers is set then Camel uses this over the endpoint configured resource. This allows you to provide a dynamic template at runtime.

Header Type Description
CamelVelocityResourceUri String Camel 2.1: A URI for the template resource to use instead of the endpoint configured.
CamelVelocityTemplate String Camel 2.1: The template to use instead of the endpoint configured.
Comments powered by Disqus