[[StringTemplate-StringTemplate]]
String Template
~~~~~~~~~~~~~~~

The *string-template:* component allows you to process a message using a
http://www.stringtemplate.org/[String Template]. This can be ideal when
using link:templating.html[Templating] to generate responses for
requests.

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

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-stringtemplate</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

[[StringTemplate-URIformat]]
URI format
^^^^^^^^^^

[source,java]
--------------------------------------
string-template:templateName[?options]
--------------------------------------

Where *templateName* is the classpath-local URI of the template to
invoke; or the complete URL of the remote template.

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

[[StringTemplate-Options]]
Options
^^^^^^^


// component options: START
The String Template component has no options.
// component options: END



// endpoint options: START
The String Template component supports 5 endpoint options which are listed below:

{% raw %}
[width="100%",cols="2,1,1m,1m,5",options="header"]
|=======================================================================
| Name | Group | Default | Java Type | Description
| resourceUri | producer |  | String | *Required* Path to the resource or a reference to lookup a bean in the Registry to use as the resource
| contentCache | producer | false | boolean | Sets whether to use resource content cache or not
| delimiterStart | producer | < | char | The variable start delimiter
| delimiterStop | producer | > | char | The variable end delimiter
| synchronous | advanced | false | boolean | Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).
|=======================================================================
{% endraw %}
// endpoint options: END


[[StringTemplate-Headers]]
Headers
^^^^^^^

Camel will store a reference to the resource in the message header with
key, `org.apache.camel.stringtemplate.resource`. The Resource is an
`org.springframework.core.io.Resource` object.

[[StringTemplate-Hotreloading]]
Hot reloading
^^^^^^^^^^^^^

The string template resource is by default hot-reloadable for both file
and classpath resources (expanded jar). If you set `contentCache=true`,
Camel loads the resource only once and hot-reloading is not possible.
This scenario can be used in production when the resource never changes.

[[StringTemplate-StringTemplateAttributes]]
StringTemplate Attributes
^^^^^^^^^^^^^^^^^^^^^^^^^

Since Camel 2.14, you can define the custom context map by setting the
message header "*CamelStringTemplateVariableMap*" just like the below
code.

[source,java]
--------------------------------------------------------------------------
Map<String, Object> variableMap = new HashMap<String, Object>();
Map<String, Object> headersMap = new HashMap<String, Object>();
headersMap.put("name", "Willem");
variableMap.put("headers", headersMap);
variableMap.put("body", "Monday");
variableMap.put("exchange", exchange);
exchange.getIn().setHeader("CamelStringTemplateVariableMap", variableMap);
--------------------------------------------------------------------------

[[StringTemplate-Samples]]
Samples
^^^^^^^

For example you could use a string template as follows in order to
formulate a response to a message:

[source,java]
-----------------------------------------------
from("activemq:My.Queue").
  to("string-template:com/acme/MyResponse.tm");
-----------------------------------------------

[[StringTemplate-TheEmailSample]]
The Email Sample
^^^^^^^^^^^^^^^^

In this sample we want to use a string template to send an order
confirmation email. The email template is laid out in `StringTemplate`
as: This example works for *camel 2.11.0*. If your camel version is less
than 2.11.0, the variables should be started and ended with $.

[source,java]
--------------------------------------------
Dear <headers.lastName>, <headers.firstName>

Thanks for the order of <headers.item>.

Regards Camel Riders Bookstore
<body>
--------------------------------------------

And the java code is as follows:

[[StringTemplate-SeeAlso]]
See Also
^^^^^^^^

* link:configuring-camel.html[Configuring Camel]
* link:component.html[Component]
* link:endpoint.html[Endpoint]
* link:getting-started.html[Getting Started]

