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");

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?")

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.