Chapter 126. Groovy Language

The Groovy language supports 1 options which are listed below.

Sometimes you may need to use custom GroovyShell instance in your Groovy expressions. To provide custom GroovyShell, add implementation of the org.apache.camel.language.groovy.GroovyShellFactory SPI interface to your Camel registry. For example after adding the following bean to your Spring context…​

public class CustomGroovyShellFactory implements GroovyShellFactory {
 
  public GroovyShell createGroovyShell(Exchange exchange) {
    ImportCustomizer importCustomizer = new ImportCustomizer();
    importCustomizer.addStaticStars("com.example.Utils");
    CompilerConfiguration configuration = new CompilerConfiguration();
    configuration.addCompilationCustomizers(importCustomizer);
    return new GroovyShell(configuration);
  }

}

…​Camel will use your custom GroovyShell instance (containing your custom static imports), instead of the default one.

// lets route if a line item is over $100
from("queue:foo").filter(groovy("request.lineItems.any { i -> i.value > 100 }")).to("queue:bar")

And the Spring DSL:

        <route>
            <from uri="queue:foo"/>
            <filter>
                <groovy>request.lineItems.any { i -> i.value > 100 }</groovy>
                <to uri="queue:bar"/>
            </filter>
        </route>

The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all set at ENGINE_SCOPE:

See Scripting Languages for the list of languages with explicit DSL support.

Available as of Camel 2.8

You can provide additional arguments to the ScriptingEngine using a header on the Camel message with the key CamelScriptArguments.
See this example:

Available as of Camel 2.9

If you need to use the Properties component from a script to lookup property placeholders, then its a bit cumbersome to do so. For example to set a header name myHeader with a value from a property placeholder, which key is provided in a header named "foo".

.setHeader("myHeader").groovy(""context.resolvePropertyPlaceholders( + '{{' + request.headers.get('foo') + '}}' + ")")

From Camel 2.9 onwards you can now use the properties function and the same example is simpler:

.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")

Available as of Camel 2.11

You can externalize the script and have Camel load it from a resource such as "classpath:", "file:", or "http:".
This is done using the following syntax: "resource:scheme:location", eg to refer to a file on the classpath you can do:

.setHeader("myHeader").groovy("resource:classpath:mygroovy.groovy")

Available as of Camel 2.14

As the scripteengine evale method just return a Null if it runs a multiple statments script. Camel now look up the value of script result by using the key of "result" from the value set. If you have multiple statements script, you need to make sure you set the value of result variable as the script return value.

bar = "baz";
# some other statements ...
# camel take the result value as the script evaluation result
result = body * 2 + 1

To use scripting languages in your camel routes you need to add a dependency on camel-groovy.

If you use Maven you could just add the following to your pom.xml, substituting the version number for the latest & greatest release (see the download page for the latest versions).

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-groovy</artifactId>
  <version>x.x.x</version>
</dependency>