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Get to know Camel’s Simple expression language in CPI


Simple is a, well, simple expression language, that ships with the Apache Camel integration framework. The language is also available in SAP Cloud Platform Integration (which I will refer to as CPI for the remainder of this post).

In CPI, Simple is mainly used to access the contents of the message being processed and its exchange, and to construct condition expressions in the Router step. The language does, however, have a few more tricks up its sleeve.

In this blog post, I will give you an overview of Simple and its features.

The basics

The most basic Simple expression is the ${ } placeholder containing a built-in variable. This example expression evaluates to the payload of the input message:


There is an alternative form, $simple{ }, which is partly supported in CPI. It does not work in Router conditions, however, so I will stick to the shorter ${ } form in this post.

In CPI, the ${ } placeholder can be inserted in e.g. the payload in a Content Modifier step or applied in the Query Editor, adding dynamic values to an OData resource path.

The ${ } placeholder can also be combined with Simple’s operators to produce boolean expressions, which you can then use as conditions in your Router steps.

Built-in variables

Simple’s built-in variables provide you with access to information such as the message payload and header fields. The list below is not exhaustive. For a list of all built-in variables, please refer to the Simple language documentation. However, keep in mind that some of them might not be supported in CPI.

Variable Description
id The ID of the message
exchangeId The ID of the exchange
body The payload of the input message The contents of the named header The contents of the named exchange property
date:now:pattern The formatted current date and time (more details below)
random(max) / random(min,max) Generates random integers (more details below)
messageHistory The history of how this exchange was processed
messageHistory(false) Similar to messageHistory, but without the contents of the exchange
camelContext Provides access to the Apache Camel runtime
exception.message The text of the current exception (or null if there’s no exception)

For more information about the camelContext variable, please see this blog post.

According to the Simple language documentation, is actually deprecated. However, the non-deprecated form,, will cause an error in CPI if used in a Router condition. This might be fixed in a future update, but for now you should stick to the deprecated form.

Date and time

The current date and time is available to you in Simple, using the date:now:pattern variable. The required pattern is a java.text.SimpleDateFormat date and time pattern string, which you might already be familiar with, if you are a Java developer. Here’s an example:

${date:now:dd-MM-yyyy HH:mm}

At the time of writing, this evaluates to 23-11-2016 06:14. The time is, however, 7:14. What gives? Let’s add the pattern letter z, in order to see the time zone:

${date:now:dd-MM-yyyy HH:mm z}

This evaluates to 23-11-2016 06:19 UTC. In other words, the time zone is Coordinated Universal Time (UTC).

To learn more about the SimpleDateFormat pattern strings, please see the class’s API documentation.

Random numbers

Should you need a random number, Simple has you covered by way of the random variable. There are two ways to employ it:

  • random(max)
  • random(min, max)

The first form generates a random integer between 0 (included) and max (excluded), while the second form generates a random integer between min (included) and max (excluded). To generate a random integer between 1 and 10, you would therefore use the following expression:

${random(1, 11)}


When adding non-XML condition routes to a Router step in your integration flow, you need to construct boolean expressions, i.e. expressions that evaluate to either true or false. The Simple language supports a range of operators, that you can use for this purpose. In the following, I will briefly describe each available operator. For a list of Simple operators supported in CPI at a given time, please refer to SAP’s documentation of the Router step.

When writing your expressions, please be aware that all literal values must be enclosed in single quotes, regardless of data type. Omitting them will cause an error. If required, the data type of the right-hand value will be converted into the data type of the left-hand value. In other words, this is a valid, numeric comparison, even though it looks like a string comparison at first glance:

${property.MyNumericProperty} > '0'

Comparison operators

The Simple language offers you the familiar comparison operators: =, !=, >, >=, < and <=. For some reason, the equality operator in CPI’s version of Simple is a single equals sign, even though it’s a double equals sign in Camel’s Simple language documentation.

Please note that string comparison is case sensitive. There’s actually a case insensitive equals operator in the Simple language (=~), but at the moment, it is not supported in CPI. In order to compare strings without considering case, you can do this instead:

${property.MyStringProperty.toLowerCase()} = 'lower case value'

For more information about calling methods, see Calling methods below.

Logical operators

The two available logical operators are and and or. According to the Simple language documentation, the and and or forms are actually deprecated, but at the time of writing, the alternative forms (&& and ||) are not supported in CPI. Keep in mind, though, that this might very well change with future CPI updates.

You can combine multiple and and or operators in the same expression, but you cannot use parentheses for grouping. Consequently, if your boolean expression is long and complex, you are probably better off moving the logic to a Script step instead, for the sake of readability and maintainability.

contains/not contains

The contains operator tests whether a string contains another string, and not contains tests whether it doesn’t contain the other string. Here’s an example:

${property.MyStringProperty} contains 'test'

As was the case with string comparison, this operator is case sensitive. To disregard case, convert to upper or lower case by calling toUpperCase() or toLowerCase(), respectively.

regex/not regex

Regular expressions are supported in the Simple language via the operators regex and not regex. The former tests whether a value matches the provided regular expression, and the latter tests whether it doesn’t match. Here’s an example that tests whether a product code is formatted as five lower-case letters followed by three digits:

${property.ProductCode} regex '^[a-z]{5}\d{3}$'

in/not in

The in operator tests whether a given value occurs in a list of values, and the not in operator tests whether it doesn’t occur in the list. Here’s an example:

${property.MyNumericProperty} in '1,2,3,4,5'

Note how the entire list in enclosed in single quotes, and how the elements are separated by commas with no whitespace around them. The data type of the list elements will automatically be converted into the data type of the left-hand side value.

When evaluating strings, keep in mind that the comparison is case sensitive. To disregard case, convert the left-hand side to upper or lower case first:

${property.MyStringProperty.toLowerCase()} in 'abc,def'

Calling methods

As we saw in the above with the toLowerCase() method of Java class String, you can call methods on objects in your expressions using the familiar dot notation.

Simple provides this functionality by supporting a subset of another Apache language called OGNL. Here’s an example:

${property.MyStringProperty.substring(0,4)} = 'test'

Here, the substring method of class String is called, and two integer parameters are passed to the method.

For straightforward method calls with scalar parameters, this works well. However, if your method invocation is more complicated, e.g. if it requires creating and passing objects to the method, moving it to a Script step is the way to go.

Also, there is a special case you need to be aware of: Examples will show method calls without parentheses, and if you are calling a method that doesn’t take any parameters, you don’t need them, unless the method is overloaded. When calling an overloaded method that takes no parameters, you need to append a pair of empty parentheses. Otherwise the call will be ambiguous, and you will end up with a runtime error.

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  • Hi Morten,

    I checked this below Date now function and its working.

    ${date:now:dd-MM-yyyy HH:mm z}

    But by default I am getting time in UTC format. My requirement is to have it in EET or IST.

    Can we achieve this timezone conversion here itself by specifying EET or need to go for scripts.?

    Kindly help me on this case.




  • Hi Morten,

    thanks for the tips about Camel’s Simple expressions. I found it really usefull, fast and efficient.

    Especially it make sense while making simple conversion of Exchange Properties like this one  ${property.ExchangeRateDate.replace(“-“,”/”)




  • Thanks a lot Morten,

    I had been looking for syntax to specify current date and the one mentioned in this blog worked perfectly. Thanks again.



      • Hi Morten,

        I need help again on the date front. My requirement is to get records from successfactors that were created yesterday. I am not sure how do I specify yesterday’s date. Could you please help?

        Also, do we have any documentation from SAP where I get all the syntax?



        • Hi Netrey

          I don’t believe that’s possible without scripting.

          Please post any follow-up questions in the Q&A section, where other community members will see and possibly respond to them.



        • Hi

          It is now possible to perform time additions on the date objects.

          You can use ${date:property.CamelCreatedTimestamp+1h}  or ${date:property.CamelCreatedTimestamp+1h}. 

          It does require you are on CF where then Camel has been updated.

          I wrote about it here.

  • Morten-

    Hope all is well. I am using following expression in my iflow to retrive data for current date.


    My understanding is that above expression will provide current date irrespective of the time zone. Using which I can schedule my iflow to run for a specific timezone. What am seeing is that data load stops after 4PM PST which is next day in UTC time zone. Is above expression in UTC, if yes please let me know if there is any expression to get the date in PST.





    • Hi Hari

      I believe the timestamp is returned in UTC. To change this, you need scripting.

      Please post any follow-up questions in the Q&A section, where other community members will see and possibly respond to them.




  • Is there any way you can obtain the user ID that executed the message? If I were to use the integration platform authenticating with IAS or SFSF, is there a way I can get the current user as an input parameter for further API calls?

  • Hi Moten,


    Hope you are doing good.


    I have a requirement to read the directory details  dynamically and pass into mapping as a input for one of the filed in CPI.

    could you please guide me the camel expression to fetch the folder details dynamically from the source SFTP.


    Thanks in advance!





  • Hi Morten,

    Thanks for sharing the very useful blog.

    I am sure that I’ll re-visit this post for many times.

    Is there anyway expression to convert UNIX date format to normal date format? Or any other way to achieve it?