Creating a Scripted State Change Processor

In this tutorial we are going to create a scripted state change processor which automatically creates an e-mail address for instances of the User entity. The e-mail address will be created by appending the values of the name and lastName parameters and the @braintribe.com domain. When you create a new instance of User, you must provide the mandatory name parameter. As our e-mail will also use the value of the lastName parameter, you will need to provide it for the processor to work.

When the value of the lastName attribute changes, the value of the e-mail attribute will be changed. This means that the lastName attribute is the watched property.

For more information on scripting in general, see Scripting.

Creating a New Scripted State Change Processor

To create a new scripted state change processor:

1. In Control Center, navigate to the State Change Processors entry point, and click New.
2. In the new window that opened, select ScriptedStateChangeProcessor and click OK.
3. Provide the externalId and name properties, click Apply and Commit. Your empty state change processor is saved

Creating and Configuring a New Script Instance

Every scripted state change processor works based on the logic provided in the Script object. You can use any of the available scripting languages: Groovy, JavaScript, or Beanshell.

To create and configure a new Script object:

1. In your newly created processor, select the script property and click Assign.
2. Select a scripting language, click Finish, and provide the logic using the scripting language you selected. In this tutorial, we are using Groovy to react to changes to the lastName property by changing the e-mail property:

def name = $context.entity.name;
def lastName =  $context.entity.lastName;
$context.entity.setEmail(name + "." + lastName + "@braintribe.com" );

When you're done writing the script, click OK and Commit. The functionality available to your script is provided by the Java API StateChangeContext. You are not limited to using Groovy - you're free to use any of the supported scripting languages.

3. Right-click your processor, and click Deploy. Your processor is now deployed.

Configuring the OnChange Metadata

A state change processor cannot function on its own. How would it know what change to react to? You must assign the OnChange metadata to the element you want to watch and trigger the logic on. In our case, it is the lastName property of the User entity type.

To configure the metadata:

1. In Control Center, navigate to Base Models and search for User Model.
2. Expand the UserModel and navigate to the properties of the User type.
3. Expand the User type, navigate to its properties, expand the lastName property, right-click the metaData property and click Add. A search window opens.
4. In the new window, search for OnChange and click Add and Finish. A new window opens.
5. In the metadata configuration window, in the processor row, click the Assign link, select your scripted state change processor, click Apply, and then Commit.

Testing Your Processor

To test your new scripted state change processor:

1. In Control Center, navigate to Custom Accesses, create a new SMOOD access, and assign the UserModel as its metamodel.
2. Switch to your new access, create a new instance of User, and commit your changes.
3. Change the value of the lastName property and click Commit. Notice that the value of the e-mail attribute changes every time you change and commit the lastName property.