http://midpoint.evolveum.com/xml/ns/public/expression/language#ECMAScript
JavaScript Expressions
JavaScript scripting expression feature
This page is an introduction to JavaScript scripting expression midPoint feature.
Please see the feature page for more details.
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ECMAScript (JavaScript) is a supported expression language in midPoint. Its language URL is:
ECMAScript support is provided by Nashorn engine. This engine fully supports ECMAScript 5.1 and many features from version 6. It was shipped with JDK 11, but it is not available in JDK 15 and later. If you want to run JDK 17, read on for instructions how to enable it. |
Activation for version 4.4 and JDK 17
Normally, to enable Nashorn we would need to download the nashorn-core.jar
with the dependencies it relies on.
There are options how to download the whole package, but the provided versions of ASM dependency are older than the one used in midPoint.
But midPoint doesn’t contain all the ASM JARs necessary for Nashorn, so some ASM JARs are still needed.
To avoid version confusion we provided a convenient download for you in the table below.
Just download the archive and extract it into $MIDPOINT_HOME/lib
directory.
midPoint version | Nashorn convenience package |
---|---|
4.4 |
If the download for a newer midPoint version is missing just try the last available download.
To be sure that ECMAScript support is enabled you can check the midpoint.log
during the startup for a line like this:
2021-10-15 23:10:16,136 [] [main] INFO (com.evolveum.midpoint.model.common.expression.script.jsr223.Jsr223ScriptEvaluator): Script engine for 'JavaScript' initialized in 393 ms.
If the engine is not initialized, following warning is emitted - this does not prevent midPoint from starting:
2021-10-15 23:12:00,042 [] [main] WARN (com.evolveum.midpoint.model.common.expression.script.jsr223.Jsr223ScriptEvaluator): The JSR-223 scripting engine for 'JavaScript' was not found
3rd party library licensing:
-
Nashorn is distributed under GPL v2 with the Classpath exception.
-
ASM is distributed under BSD-3-Clause.
Examples
User name
Following code returns a name
property of a user.
It is using ternary operator (?
and :
) to make sure this code works as expected even if user is null
. User can be null
is some situations, such as when evaluating outbound expression for a deleted user.
Therefore, the use of similar safe constructs is advised in almost all situations.
user == null ? null : user.getName();
Create fullName
user.getGivenName() + ' ' + user.getFamilyName();