Camel xtrasonnet Language¶

Since Camel 3.20

The Camel xtrasonnet component enables the use xtrasonnet transformations as Expressions or Predicates in the DSL.

Getting started¶

Add the following maven dependency

<dependency>
  <groupId>io.github.jam01</groupId>
  <artifactId>camel-xtrasonnet</artifactId>
  <version>0.6.1</version>
</dependency>

and simply create an xtrasonnet expression:

import static io.github.jam01.camel.builder.XtrasonnetBuilder.xtrasonnet;

xtrasonnet(myXtrasonnet)

Examples¶

Here is a simple example using a xtrasonnet expression as a predicate in a Message Filter, it will filter messages if any element in lineItems is over 100.

// lets route if a line item is over $100
from("direct:filter")
    .filter(xtrasonnet("xtr.arrays.any(payload.lineItems, function(item) item > 100)"))
    .to("mock:result");

And the XML DSL:

<route id="xml-filter">
    <from uri="direct:xml-filter"/>
    <filter>
        <language language="xtrasonnet">
            xtr.arrays.any(payload.lineItems, function(item) item > 100)
        </language>
        <to uri="mock:xml-result"/>
    </filter>
</route>

Here is an example of a simple xtrasonnet expression in a transformation EIP.

from("direct:transform")
    .transform(xtrasonnet("payload.lineItems", String.class)
        .bodyMediaType(MediaTypes.APPLICATION_XML)
        .outputMediaType(MediaTypes.APPLICATION_JSON))
    .to("mock:result");

And the XML DSL:

<route id="xml-transform">
    <from uri="direct:xml-transform"/>
    <setProperty name="CamelXtrasonnetBodyMediaType"><constant>application/xml</constant></setProperty>
    <setProperty name="CamelXtrasonnetOutputMediaType"><constant>application/json</constant></setProperty>
    <setProperty name="CamelXtrasonnetResultType"><constant>java.lang.String</constant></setProperty>
    <transform>
        <language language="xtrasonnet">payload.lineItems</language>
    </transform>
    <to uri="mock:xml-result"/>
</route>

Specifying result type¶

The xtrasonnet expression will return a io.github.jam01.xtrasonnet.document.Document by default. The document preserves the content type metadata along with the contents of the result of the transformation. In predicates, however, the Document will be automatically unwrapped and the boolean content will be returned. Similarly any time you want the content in a specific type, like a String, you have to instruct the xtrasonnet to do so.

In Java DSL:

xtrasonnet("payload.foo", String.class)

In XML DSL you use CamelXtrasonnetResultType as an exchange property or message header to provide a fully qualified classname:

<setProperty name="CamelXtrasonnetResultType"><constant>java.lang.String</constant></setProperty>
<language language="xtrasonnet">payload.foo</language>

If the expression results in an Array, or an Object, you can instruct the expression to return you List.class or Map.class, respectively. However, the output media type must be application/x-java-object (default).

Specifying media types¶

A few options are provided for specifying the body and output media types. The xtrasonnet expression will look for a body media type in the following order:

1. If the body is a Document, it will use the metadata in the object
2. If the bodyMediaType() builder method was used, it will use its value
3. A "CamelXtrasonnetBodyMediaType" exchange property or message header
4. A "Content-Type" message header
5. The xtrasonnet Header payload input media type directive
6. application/x-java-object

And for output media type:

1. If the outputMediaType() builder method was used, it will use its value
2. A "CamelXtrasonnetBodyMediaType" exchange property or message header
3. The xtrasonnet Header output media type directive
4. application/x-java-object

cml Library¶

The Camel xtrasonnet component adds the following xtrasonnet functions that can be used to access the exchange:

Here's an example showing some of these functions in use:

from("direct:cml")
    .setBody(xtrasonnet("'hello ' + cml.properties('toGreet')", String.class))
    .to("mock:result");

And the XML DSL:

<route id="xml-cml">
    <from uri="direct:xml-cml"/>
    <setProperty name="CamelXtrasonnetResultType"><constant>java.lang.String</constant></setProperty>
    <setBody>
        <language language="xtrasonnet">'hello ' + cml.properties('toGreet')</language>
    </setBody>
    <to uri="mock:xml-result"/>
</route>

Expression from resource¶

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", e.g.: to refer to a file on the classpath you can do:

from("direct:resource")
    .setHeader("myHeader", xtrasonnet("resource:classpath:myXtrasonnet.xtr", String.class))
    .to("mock:result")