Camel Components

Set Variables

The SetVariables EIP is used for setting multiple Exchange variables at the same time.

Options

The Set Variables eip supports the following options which are listed below.

Name Description Default Type

note

The note for this node.

String

description

The description for this node.

String

disabled

Whether to disable this EIP from the route during build time. Once an EIP has been disabled then it cannot be enabled later at runtime.

false

Boolean

variables

Required Contains the variables to be set.

List

Message Body

The message body at each side of the Set Variables EIP: EIP input is the body it needs, EIP output the body after it, and Steps the body its own steps start with.

Side Body Description

EIP output

unchanged

Sets variables: the body stays as it was.

The bodies are the ones with the default options. A side that is not listed is not known, and tooling does not guess it. The carriers are described in the Camel Catalog.

Exchange properties

The Set Variables eip has no exchange properties.

Using Set Variables

The following example shows how to set multiple variables in a Camel route using Java, XML or YAML. Note that the syntax is slightly different in each case.

  • Java

  • XML

  • YAML

from("direct:a")
    .setVariables("myVar", constant("test"), "otherVar", constant("other"))
    .to("direct:b");
<route>
    <from uri="direct:a"/>
    <setVariables>
        <setVariable name="myVar">
            <constant>test</constant>
        </setVariable>
        <setVariable name="otherVar">
            <constant>other</constant>
        </setVariable>
    </setVariables>
    <to uri="direct:b"/>
</route>
- route:
    from:
      uri: direct:a
      steps:
        - setVariables:
            variables:
              - name: myVar
                constant: test
              - name: otherVar
                constant: other
        - to:
            uri: direct:b

For example, the variables values are constants.

Any of the Camel languages can be used, such as Simple.

  • Java

  • XML

  • YAML

from("direct:a")
    .setVariables("randomNumber", simple("${random(1,100)}"), "body", simple("${body}"))
    .to("direct:b");
<route>
    <from uri="direct:a"/>
    <setVariables>
        <setVariable name="randomNumber">
            <simple>${random(1,100)}</simple>
        </setVariable>
        <setVariable name="body">
            <simple>${body}</simple>
        </setVariable>
    </setVariables>
    <to uri="direct:b"/>
</route>
- route:
    from:
      uri: direct:a
      steps:
        - setVariables:
            variables:
              - name: randomNumber
                expression:
                  simple:
                    expression: "${random(1,100)}"
              - name: body
                expression:
                  simple:
                    expression: "${body}"
        - to:
            uri: direct:b

Setting a variable from another variable

You can also set several variables where later ones depend on earlier ones.

In the example, we first set the variable foo to the body and then set bar based on comparing foo with a value.

  • Java

  • XML

  • YAML

from("direct:a")
    .setVariables("foo", simple("${body}"), "bar", simple("${variable.foo} > 10", Boolean.class))
    .to("direct:b");
<route>
    <from uri="direct:a"/>
    <setVariables>
        <setVariable name="foo">
            <simple>${body}</simple>
        </setVariable>
        <setVariable name="bar">
            <simple resultType="java.lang.Boolean">${variable.foo} > 10</simple>
        </setVariable>
    </setVariables>
    <to uri="direct:b"/>
</route>
- route:
    from:
      uri: direct:a
      steps:
        - setVariables:
            variables:
              - name: foo
                expression:
                  simple:
                    expression: "${body}"
              - name: bar
                expression:
                  simple:
                    expression: "${variable.foo} > 10"
                    resultType: "boolean"
        - to:
            uri: direct:b

Using a Map with Java DSL

It’s also possible to build a Map and pass it as the single argument to setVariables(). If the order in which the variables should be set is important, use a LinkedHashMap.

Java-only: using a LinkedHashMap to set variables in order
Map<String, Expression> variableMap = new java.util.LinkedHashMap<>();
variableMap.put("foo", ConstantLanguage.constant("ABC"));
variableMap.put("bar", ConstantLanguage.constant("XYZ"));

from("direct:startMap")
    .setVariables(variableMap)
    .to("direct:b");

If the ordering is not critical, then Map.of(name1, expr1, name2, expr2…​) can be used.

Java-only: using Map.of for unordered variables
from("direct:startMap")
    .setVariables(Map.of("foo", "ABC", "bar", "XYZ"))
    .to("direct:b");