Language Component

Since Camel 2.5

Only producer is supported

The Language component allows you to send Exchange to an endpoint which executes a script by any of the supported Languages in Camel.
By having a component to execute language scripts, it allows more dynamic routing capabilities. For example by using the Routing Slip or Dynamic Router EIPs you can send messages to language endpoints where the script is dynamic defined as well.

This component is provided out of the box in camel-core and hence no additional JARs is needed. You only have to include additional Camel components if the language of choice mandates it, such as using Groovy or JavaScript languages.

URI format

language://languageName[:script][?options]

You can refer to an external resource for the script using same notation as supported by the other Languages in Camel

language://languageName:resource:scheme:location][?options]

URI Options

The Language component supports 3 options, which are listed below.

Name Description Default Type

basicPropertyBinding (advanced)

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

The Language endpoint is configured using URI syntax:

language:languageName:resourceUri

with the following path and query parameters:

Path Parameters (2 parameters):

Name Description Default Type

languageName

Required Sets the name of the language to use

String

resourceUri

Path to the resource, or a reference to lookup a bean in the Registry to use as the resource

String

Query Parameters (8 parameters):

Name Description Default Type

binary (producer)

Whether the script is binary content or text content. By default the script is read as text content (eg java.lang.String)

false

boolean

cacheScript (producer)

Whether to cache the compiled script and reuse Notice reusing the script can cause side effects from processing one Camel org.apache.camel.Exchange to the next org.apache.camel.Exchange.

false

boolean

contentCache (producer)

Sets whether to use resource content cache or not

true

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

script (producer)

Sets the script to execute

String

transform (producer)

Whether or not the result of the script should be used as message body. This options is default true.

true

boolean

basicPropertyBinding (advanced)

Whether the endpoint should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

boolean

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

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

The component supports 4 options, which are listed below.

Name Description Default Type

camel.component.language.basic-property-binding

Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities

false

Boolean

camel.component.language.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.language.enabled

Whether to enable auto configuration of the language component. This is enabled by default.

Boolean

camel.component.language.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

Message Headers

The following message headers can be used to affect the behavior of the component

Header Description

CamelLanguageScript

The script to execute provided in the header. Takes precedence over script configured on the endpoint.

Examples

For example you can use the Simple language to Message Translator a message:

In case you want to convert the message body type you can do this as well:

You can also use the Groovy language, such as this example where the input message will by multiplied with 2:

You can also provide the script as a header as shown below. Here we use XPath language to extract the text from the <foo> tag.

Object out = producer.requestBodyAndHeader("language:xpath", "<foo>Hello World</foo>", Exchange.LANGUAGE_SCRIPT, "/foo/text()");
assertEquals("Hello World", out);

Loading scripts from resources

Since Camel 2.9

You can specify a resource uri for a script to load in either the endpoint uri, or in the Exchange.LANGUAGE_SCRIPT header.
The uri must start with one of the following schemes: file:, classpath:, or http:

For example to load a script from the classpath:

By default the script is loaded once and cached. However you can disable the contentCache option and have the script loaded on each evaluation.
For example if the file myscript.txt is changed on disk, then the updated script is used:

You can refer to the resource similar to the other Languages in Camel by prefixing with "resource:" as shown below: