Chunk

Available as of Camel 2.15

The chunk: component allows for processing a message using a Chunk template. This can be ideal when using Templating to generate responses for requests.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-chunk</artifactId>
<version>x.x.x</version> <!-- use the same version as your Camel core version -->
</dependency>

URI format

chunk:templateName[?options]

Where templateName is the classpath-local URI of the template to invoke.

You can append query options to the URI in the following format, ?option=value&option=value&...

Options

Option	Default	Description
`encoding`	`null`	Character encoding of the resource content.
themesFolder	`null`	Alternative folder to scan for a template name.
themeSubfolder	`null`	Alternative subfolder to scan for a template name if themeFolder parameter is set.
`themeLayer`	`null`	A specific layer of a template file to use as template.
`extension`	`null`	Alternative extension to scan for a template name if themeFolder and themeSubfolder are set.

Chunk component will look for a specific template in themes folder with extensions .chtml or .cxml. If you need to specify a different folder or extensions, you will need to use the specific options listed above.

Chunk Context

Camel will provide exchange information in the Chunk context (just a Map). The Exchange is transferred as:

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

Dynamic templates

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	Support Version
ChunkConstants.CHUNK_RESOURCE_URI	String	A URI for the template resource to use instead of the endpoint configured.
ChunkConstants.CHUNK_TEMPLATE	String	The template to use instead of the endpoint configured.

Samples

For example you could use something like:

from("activemq:My.Queue").
to("chunk:template");

To use a Chunk 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("chunk:template").
to("activemq:Another.Queue");

It's possible to specify what template the component should use dynamically via a header, so for example:

from("direct:in").
setHeader(ChunkConstants.CHUNK_RESOURCE_URI).constant("template").
to("chunk:dummy");

An example of Chunk component options use:

from("direct:in").
to("chunk:file_example?themeFolder=template&themeSubfolder=subfolder&extension=chunk");

In this example Chunk component will look for the file file_example.chunk in the folder template/subfolder.

The Email Sample

In this sample we want to use Chunk templating for an order confirmation email. The email template is laid out in Chunk as:

 
Dear {$headers.lastName}, {$headers.firstName}

Thanks for the order of {$headers.item}.

Regards Camel Riders Bookstore
{$body}

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