[CONF] Apache Camel: Velocity (page edited)

confluence Thu, 05 Jun 2008 03:49:37 -0700

Page Edited : CAMEL : Velocity

Velocity has been edited by Claus Ibsen (Jun 05, 2008).

Content:

Velocity

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.

URI format

velocity:templateName

Where templateName is the classpath-local URI of the template to invoke; or the complete URL of the remote template (eg: file://folder/myfile.vm).

Options

Option	Default	Description
loaderCache	true	Velocity based file loader cache
contentCache	false	New option in Camel 1.4. Cache for the resource content when its loaded.

Hot reloading

The velocity template resource is by default hot reloadable for both file and classpath resources (expanded jar). Setting the contentCache=true then Camel will only load the resource once, and thus hot reloading is not possible. This scenario can be used in production usage when the resource never changes.

Samples

For example you could use something like

from("activemq:My.Queue").
  to("velocity:com/acme/MyResponse.vm");

To use a velocity template to formulate a response for a message for InOut message exchanges (where there is a JMSReplyTo header).

If you want to use InOnly and consume the message and send it to another destination you could use

from("activemq:My.Queue").
  to("velocity:com/acme/MyResponse.vm").
  to("activemq:Another.Queue");

And to use content cache, eg. for production usage where the .vm template never changes:

from("activemq:My.Queue").
  to("velocity:com/acme/MyResponse.vm?contentCache=true").
  to("activemq:Another.Queue");

And a file based resource:

from("activemq:My.Queue").
  to("velocity:file://myfolder/MyResponse.vm?contentCache=true").
  to("activemq:Another.Queue");