Search

Chapter 29. The Simple Language

download PDF

Abstract

The simple language is a language that was developed in Apache Camel specifically for the purpose of accessing and manipulating the various parts of an exchange object. The language is not quite as simple as when it was originally created and it now features a comprehensive set of logical operators and conjunctions.

29.1. Java DSL

Simple expressions in Java DSL

In the Java DSL, there are two styles for using the simple() command in a route. You can either pass the simple() command as an argument to a processor, as follows:
from("seda:order")
  .filter(simple("${in.header.foo}"))
  .to("mock:fooOrders");
Or you can call the simple() command as a sub-clause on the processor, for example:
from("seda:order")
  .filter()
  .simple("${in.header.foo}")
  .to("mock:fooOrders");

Embedding in a string

If you are embedding a simple expression inside a plain text string, you must use the placeholder syntax, ${Expression}. For example, to embed the in.header.name expression in a string:
simple("Hello ${in.header.name}, how are you?")

Customizing the start and end tokens

From Java, you can customize the start and end tokens ({ and }, by default) by calling the changeFunctionStartToken static method and the changeFunctionEndToken static method on the SimpleLanguage object.
For example, you can change the start and end tokens to [ and ] in Java, as follows:
// Java
import org.apache.camel.language.simple.SimpleLanguage;
...
SimpleLanguage.changeFunctionStartToken("[");
SimpleLanguage.changeFunctionEndToken("]");
Note
Customizing the start and end tokens affects all Apache Camel applications that share the same camel-core library on their classpath. For example, in an OSGi server this might affect many applications; whereas in a Web application (WAR file) it would affect only the Web application itself.
Red Hat logoGithubRedditYoutubeTwitter

Learn

Try, buy, & sell

Communities

About Red Hat Documentation

We help Red Hat users innovate and achieve their goals with our products and services with content they can trust.

Making open source more inclusive

Red Hat is committed to replacing problematic language in our code, documentation, and web properties. For more details, see the Red Hat Blog.

About Red Hat

We deliver hardened solutions that make it easier for enterprises to work across platforms and environments, from the core datacenter to the network edge.

© 2024 Red Hat, Inc.