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Variable	Type	Description
camelId	String	Camel 2.10: the CamelContext name
camelContext.OGNL	Object	Camel 2.11: the CamelContext invoked using a Camel OGNL expression.
exchangeId	String	Camel 2.3: the exchange id
id	String	the input message id
body	Object	the input body
in.body	Object	the input body
body.OGNL	Object	Camel 2.3: the input body invoked using a Camel OGNL expression.
in.body.OGNL	Object	Camel 2.3: the input body invoked using a Camel OGNL expression.
bodyAs(type)	Type	Camel 2.3: Converts the body to the given type determined by its classname. The converted body can be null.
mandatoryBodyAs(type)	Type	Camel 2.5: Converts the body to the given type determined by its classname, and expects the body to be not null.
out.body	Object	the output body
header.foo	Object	refer to the input foo header
header[foo]	Object	Camel 2.9.2: refer to the input foo header
headers.foo	Object	refer to the input foo header
headers[foo]	Object	Camel 2.9.2: refer to the input foo header
in.header.foo	Object	refer to the input foo header
in.header[foo]	Object	Camel 2.9.2: refer to the input foo header
in.headers.foo	Object	refer to the input foo header
in.headers[foo]	Object	Camel 2.9.2: refer to the input foo header
header.foo[bar]	Object	Camel 2.3: regard input foo header as a map and perform lookup on the map with bar as key
in.header.foo[bar]	Object	Camel 2.3: regard input foo header as a map and perform lookup on the map with bar as key
in.headers.foo[bar]	Object	Camel 2.3: regard input foo header as a map and perform lookup on the map with bar as key
header.foo.OGNL	Object	Camel 2.3: refer to the input foo header and invoke its value using a Camel OGNL expression.
in.header.foo.OGNL	Object	Camel 2.3: refer to the input foo header and invoke its value using a Camel OGNL expression.
in.headers.foo.OGNL	Object	Camel 2.3: refer to the input foo header and invoke its value using a Camel OGNL expression.
out.header.foo	Object	refer to the out header foo
out.header[foo]	Object	Camel 2.9.2: refer to the out header foo
out.headers.foo	Object	refer to the out header foo
out.headers[foo]	Object	Camel 2.9.2: refer to the out header foo
headerAs(key,type)	Type	Camel 2.5: Converts the header to the given type determined by its classname
headers	Map	Camel 2.9: refer to the input headers
in.headers	Map	Camel 2.9: refer to the input headers
property.foo	Object	refer to the foo property on the exchange
property[foo]	Object	Camel 2.9.2: refer to the foo property on the exchange
property.foo.OGNL	Object	Camel 2.8: refer to the foo property on the exchange and invoke its value using a Camel OGNL expression.
sys.foo	String	refer to the system property
sysenv.foo	String	Camel 2.3: refer to the system environment
exception	Object	Camel 2.4: Refer to the exception object on the exchange, is null if no exception set on exchange. Will fallback and grab caught exceptions (`Exchange.EXCEPTION_CAUGHT`) if the Exchange has any.
exception.OGNL	Object	Camel 2.4: Refer to the exchange exception invoked using a Camel OGNL expression object
exception.message	String	Refer to the exception.message on the exchange, is null if no exception set on exchange. Will fallback and grab caught exceptions (`Exchange.EXCEPTION_CAUGHT`) if the Exchange has any.
exception.stacktrace	String	Camel 2.6. Refer to the exception.stracktrace on the exchange, is null if no exception set on exchange. Will fallback and grab caught exceptions (`Exchange.EXCEPTION_CAUGHT`) if the Exchange has any.
date:command:pattern	String	Date formatting using the `java.text.SimpleDataFormat` patterns. Supported commands are: now for current timestamp, in.header.xxx or header.xxx to use the Date object in the IN header with the key xxx. out.header.xxx to use the Date object in the OUT header with the key xxx.
bean:bean expression	Object	Invoking a bean expression using the Bean language. Specifying a method name you must use dot as separator. We also support the ?method=methodname syntax that is used by the Bean component.
properties:locations:key	String	Deprecated (use properties-location instead) Camel 2.3: Lookup a property with the given key. The `locations` option is optional. See more at Using PropertyPlaceholder.
properties-location:locations:key	String	Camel 2.3: Lookup a property with the given key. The `locations` option is optional. See more at Using PropertyPlaceholder.
properties:key:default	String	Camel 2.14.1: Lookup a property with the given key. If the key does not exists or has no value, then an optional default value can be specified.
routeId	String	Camel 2.11: Returns the id of the current route the Exchange is being routed.
threadName	String	Camel 2.3: Returns the name of the current thread. Can be used for logging purpose.
ref:xxx	Object	Camel 2.6: To lookup a bean from the Registry with the given id.
type:name.field	Object	Camel 2.11: To refer to a type or field by its FQN name. To refer to a field you can append .FIELD_NAME. For example you can refer to the constant field from Exchange as: `org.apache.camel.Exchange.FILE_NAME`	.
null		Camel 2.12.3: represents a null

...

Then you can use Camel OGNL notation to access the address object:

Code Block
simple("${body.address}") simple("${body.address.street}") simple("${body.address.zip}")

Camel understands the shorthand names for getters, but you can invoke any method or use the real name such as:

Code Block
simple("${body.address}") simple("${body.getAddress.getStreet}") simple("${body.address.getZip}") simple("${body.doSomething}")

You can also use the null safe operator (?.) to avoid NPE if for example the body does NOT have an address

Code Block
simple("${body?.address?.street}")

Its also possible to index in Map or List types, so you can do:

Code Block
simple("${body[foo].name}")

...

Info

	key with spaces
	key with spaces

If the key has space, then you must enclose the key with quotes, for example 'foo bar':

Code Block
simple("${body['foo bar'].name}")

You can access the Map or List objects directly using their key name (with or without dots) :

Code Block
simple("${body[foo]}") simple("${body[this.is.foo]}")

Suppose there was no value with the key foo then you can use the null safe operator to avoid the NPE as shown:

Code Block
simple("${body[foo]?.name}")

You can also access List types, for example to get lines from the address you can do:

Code Block
simple("${body.address.lines[0]}") simple("${body.address.lines[1]}") simple("${body.address.lines[2]}")

There is a special last keyword which can be used to get the last value from a list.

Code Block
simple("${body.address.lines[last]}")

And to get the 2nd last you can subtract a number, so we can use last-1 to indicate this:

Code Block
simple("${body.address.lines[last-1]}")

And the 3rd last is of course:

Code Block
simple("${body.address.lines[last-2]}")

And you can call the size method on the list with

Code Block
simple("${body.address.lines.size}")

From Camel 2.11.1 onwards we added support for the length field for Java arrays as well, eg:

Code Block
String[] lines = new String[]{"foo", "bar", "cat"}; exchange.getIn().setBody(lines); simple("There are ${body.length} lines")

And yes you can combine this with the operator support as shown below:

Code Block
simple("${body.address.zip} > 1000")

...

To enable it the left value must be enclosed in ${ }. The syntax is:

Code Block
${leftValue} OP rightValue

...

The syntax for AND is:

Code Block
${leftValue} OP rightValue and ${leftValue} OP rightValue

And the syntax for OR is:

Code Block
${leftValue} OP rightValue or ${leftValue} OP rightValue

Some examples:

Code Block


simple("${in.header.foo} == 'foo'")

// here Camel will type convert '100' into the type of in.header.bar and if its an Integer '100' will also be converter to an Integer
simple("${in.header.bar} == '100'")

simple("${in.header.bar} == 100")

// 100 will be converter to the type of in.header.bar so we can do > comparison
simple("${in.header.bar} > 100")

Info

title	Comparing with different types

When you compare with different types such as String and int, then you have to take a bit care. Camel will use the type from the left hand side as 1st priority. And fallback to the right hand side type if both values couldn't be compared based on that type.
This means you can flip the values to enforce a specific type. Suppose the bar value above is a String. Then you can flip the equation:

Code Block
simple("100 < ${in.header.bar}")

which then ensures the int type is used as 1st priority.

This may change in the future if the Camel team improves the binary comparison operations to prefer numeric types over String based. It's most often the String type which causes problem when comparing with numbers.

Code Block
// testing for null simple("${in.header.baz} == null") // testing for not null simple("${in.header.baz} != null")

And a bit more advanced example where the right value is another expression

Code Block
simple("${in.header.date} == ${date:now:yyyyMMdd}") simple("${in.header.type} == ${bean:orderService?method=getOrderType}")

And an example with contains, testing if the title contains the word Camel

Code Block
simple("${in.header.title} contains 'Camel'")

And an example with regex, testing if the number header is a 4 digit value:

Code Block
simple("${in.header.number} regex '\\d{4}'")

And finally an example if the header equals any of the values in the list. Each element must be separated by comma, and no space around.
This also works for numbers etc, as Camel will convert each element into the type of the left hand side.

Code Block
simple("${in.header.type} in 'gold,silver'")

And for all the last 3 we also support the negate test using not:

Code Block
simple("${in.header.type} not in 'gold,silver'")

And you can test if the type is a certain instance, eg for instance a String

Code Block
simple("${in.header.type} is 'java.lang.String'")

We have added a shorthand for all java.lang types so you can write it as:

Code Block
simple("${in.header.type} is 'String'")

Ranges are also supported. The range interval requires numbers and both from and end are inclusive. For instance to test whether a value is between 100 and 199:

Code Block
simple("${in.header.number} range 100..199")

...

From Camel 2.9 onwards the range value must be in single quotes

Code Block
simple("${in.header.number} range '100..199'")

Tip

title	Can be used in Spring XML

As the Spring XML does not have all the power as the Java DSL with all its various builder methods, you have to resort to use some other languages
for testing with simple operators. Now you can do this with the simple language. In the sample below we want to test if the header is a widget order:

Code Block

	xml
	xml


    <from uri="seda:orders">
       <filter>
           <simple>${in.header.type} == 'widget'</simple>
           <to uri="bean:orderService?method=handleWidget"/>
       </filter>
    </from>

...

Tip

title	Camel 2.9 onwards

Use && or || from Camel 2.9 onwards.

For instance:

Code Block
simple("${in.header.title} contains 'Camel' and ${in.header.type'} == 'gold'")

And of course the or is also supported. The sample would be:

Code Block
simple("${in.header.title} contains 'Camel' or ${in.header.type'} == 'gold'")

Notice: Currently and or or can only be used once in a simple language expression. This might change in the future.
So you cannot do:

Code Block
simple("${in.header.title} contains 'Camel' and ${in.header.type'} == 'gold' and ${in.header.number} range 100..200")

...

In the Spring XML sample below we filter based on a header value:

Code Block

	xml
	xml


    <from uri="seda:orders">
       <filter>
           <simple>${in.header.foo}</simple>
           <to uri="mock:fooOrders"/>
       </filter>
    </from>

...

The same example in Java DSL:

Code Block

	java
	java


    from("seda:orders")
        .filter().simple("${in.header.foo}").to("seda:fooOrders");

You can also use the simple language for simple text concatenations such as:

Code Block

	java
	java


   from("direct:hello").transform().simple("Hello ${in.header.user} how are you?").to("mock:reply");

...

And this sample uses the date command to output current date.

Code Block

	java
	java


   from("direct:hello").transform().simple("The today is ${date:now:yyyyMMdd} and its a great day.").to("mock:reply");

And in the sample below we invoke the bean language to invoke a method on a bean to be included in the returned string:

Code Block

	java
	java


   from("direct:order").transform().simple("OrderId: ${bean:orderIdGenerator}").to("mock:reply");

...

If we want to declare which method to invoke on the order id generator bean we must prepend .method name such as below where we invoke the generateId method.

Code Block

	java
	java


   from("direct:order").transform().simple("OrderId: ${bean:orderIdGenerator.generateId}").to("mock:reply");

We can use the ?method=methodname option that we are familiar with the Bean component itself:

Code Block

	java
	java


   from("direct:order").transform().simple("OrderId: ${bean:orderIdGenerator?method=generateId}").to("mock:reply");

And from Camel 2.3 onwards you can also convert the body to a given type, for example to ensure its a String you can do:

Code Block

	xml
	xml


  <transform>
    <simple>Hello ${bodyAs(String)} how are you?</simple>
  </transform>

...

Its also possible to lookup a value from a header Map in Camel 2.3 onwards:

Code Block

	xml
	xml


  <transform>
    <simple>The gold value is ${header.type[gold]}</simple>
  </transform>

...

From Camel 2.9 onwards you can nest functions, such as shown below:

Code Block

	xml
	xml


<setHeader headerName="myHeader">
  <simple>${properties:${header.someKey}}</simple>
</setHeader>

...

From Camel 2.9.3 onwards its easier to specify new lines or tabs in XML DSLs as you can escape the value now

Code Block

	xml
	xml


<transform>
  <simple>The following text\nis on a new line</simple>
</transform>

...

For example to set a header as a boolean type you can do:

Code Block
.setHeader("cool", simple("true", Boolean.class))

And in XML DSL

Code Block

	xml
	xml


      <setHeader headerName="cool">
        <!-- use resultType to indicate that the type should be a java.lang.Boolean -->
        <simple resultType="java.lang.Boolean">true</simple>
      </setHeader>

...

You can configure the function start and end tokens - ${ } using the setters changeFunctionStartToken and changeFunctionEndToken on SimpleLanguage, using Java code. From Spring XML you can define a <bean> tag with the new changed tokens in the properties as shown below:

Code Block

	xml
	xml


    <!-- configure Simple to use custom prefix/suffix tokens -->
    <bean id="simple" class="org.apache.camel.language.simple.SimpleLanguage">
      <property name="functionStartToken" value="["/>
      <property name="functionEndToken" value="]"/>
    </bean>

...

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:

Code Block
.setHeader("myHeader").simple("resource:classpath:mysimple.txt")

...

You can set a spring bean into an exchange property as shown below:

Code Block

	xml
	xml


<bean id="myBeanId" class="my.package.MyCustomClass" />
...
<route>
  ...
  <setProperty propertyName="monitoring.message">
    <simple>ref:myBeanId</simple>
  </setProperty>
  ...
</route>

...

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