Chapter 59. Chunk Component
Available as of Camel version 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>
59.1. 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&…
59.2. Options
The Chunk component has no options.
The Chunk endpoint is configured using URI syntax:
chunk:resourceUri
with the following path and query parameters:
59.2.1. Path Parameters (1 parameters):
Name | Description | Default | Type |
---|---|---|---|
resourceUri | Required Path to the resource. You can prefix with: classpath, file, http, ref, or bean. classpath, file and http loads the resource using these protocols (classpath is default). ref will lookup the resource in the registry. bean will call a method on a bean to be used as the resource. For bean you can specify the method name after dot, eg bean:myBean.myMethod. | String |
59.2.2. Query Parameters (7 parameters):
Name | Description | Default | Type |
---|---|---|---|
contentCache (producer) | Sets whether to use resource content cache or not | false | boolean |
encoding (producer) | Define the encoding of the body | String | |
extension (producer) | Define the file extension of the template | String | |
themeFolder (producer) | Define the themes folder to scan | String | |
themeLayer (producer) | Define the theme layer to elaborate | String | |
themeSubfolder (producer) | Define the themes subfolder to scan | String | |
synchronous (advanced) | Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). | false | boolean |
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.
59.3. Chunk Context
Camel will provide exchange information in the Chunk context (just a Map
). The Exchange
is transferred as:
key | value |
---|---|
|
The |
|
The |
| The headers of the In message. |
| The Camel Context. |
| The In message. |
| The In message body. |
| The Out message (only for InOut message exchange pattern). |
59.4. 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. |
59.5. 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.
59.6. 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}
59.7. See Also
- Configuring Camel
- Component
- Endpoint
- Getting Started