| = String Template Component |
| :doctitle: String Template |
| :shortname: string-template |
| :artifactid: camel-stringtemplate |
| :description: Transform messages using StringTemplate engine. |
| :since: 1.2 |
| :supportlevel: Stable |
| :tabs-sync-option: |
| :component-header: Only producer is supported |
| //Manually maintained attributes |
| :camel-spring-boot-name: stringtemplate |
| |
| *Since Camel {since}* |
| |
| *{component-header}* |
| |
| The String Template component allows you to process a message using a |
| http://www.stringtemplate.org/[String 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: |
| |
| [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> |
| ------------------------------------------------------------ |
| |
| == URI format |
| |
| -------------------------------------- |
| string-template:templateName[?options] |
| -------------------------------------- |
| |
| Where *templateName* is the classpath-local URI of the template to |
| invoke; or the complete URL of the remote template. |
| |
| |
| |
| // component-configure options: START |
| |
| // component-configure options: END |
| |
| // component options: START |
| include::partial$component-configure-options.adoc[] |
| include::partial$component-endpoint-options.adoc[] |
| // component options: END |
| |
| // endpoint options: START |
| |
| // endpoint options: END |
| // component headers: START |
| include::partial$component-endpoint-headers.adoc[] |
| // component headers: END |
| |
| == 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. |
| |
| == 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. |
| |
| == 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. |
| |
| == StringTemplate Attributes |
| |
| 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); |
| -------------------------------------------------------------------------- |
| |
| == 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"); |
| ----------------------------------------------- |
| |
| == 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: |
| |
| -------------------------------------------- |
| Dear <headers.lastName>, <headers.firstName> |
| |
| Thanks for the order of <headers.item>. |
| |
| Regards Camel Riders Bookstore |
| <body> |
| -------------------------------------------- |
| |
| And the java code is as follows: |
| |
| include::spring-boot:partial$starter.adoc[] |
