Lightning Process Builder and Invocable Methods

Overview

The new Lightning Process Builder (which I’ve take to calling workflow on steroids) goes GA with the Spring 15 release, introducing a greater number of declarative actions that can be taken when a record matches specified criteria:

• Create a record (not just tasks!)
• Update any related record (not just immediate parent)
• Launch a headless flow
• Quick action
• Send an email
• Post to chatter
• Submit record for approval

If the above actions don’t cater for your particular requirements, you have the final and killer action:

• Execute Apex method

This allows you to execute custom Apex code, and once you are in Apex-land you can do pretty much anything you need to.

@InvocableMethod Annotation

In order to allow an Apex method to be executed as a Process Builder action, you need to use the @InvocableMethod annotation. 

Example

Here’s an example of using an invocable annotation that I built for the BrightGen Spring 15 Salesforce Release Webinar around account validation. There are a couple of processes involved.

Process 1 - Create Validation Tasks

When an account is created that is unvalidated, send emails to key users asking them to validate the account:

Process 2 - Clean up Validation Tasks

Once the account is changed to validated, delete the task records - this involves invoking an Apex method as there is no action to delete a record (although hopefully this is something that will be introduced in a  future release):

Defining an apex action is straightforward - simply choose the Action Type of ‘Apex’, give the action a name and then choose from the available classes that contain methods annotated with @InvocableMethod:

Apex Method

The TaskUtils task contains a single method that is passed the id(s) of the accounts whose validation tasks are to be deleted, locates the validation tasks based on their name and deletes them:

public class TasksUtils
{
    @InvocableMethod
    public static void AccountValidated(List<Id> accountIds)
    {
        List<Task> tasks=[select id from Task
                          where whatId in :accountIds
                          and Subject = 'Validate Account'];

        delete tasks;
    }
}

Creating an account that is unvalidated automatically adds 2 tasks:

and updating the record to validated automatically deletes these tasks:

Comparison With Trigger

Looking again at the Apex method, there no code aside from that to locate the tasks and delete them:

public static void AccountValidated(List<Id> accountIds)
{
    List<Task> tasks=[select id from Task
                      where whatId in :accountIds
                      and Subject = 'Validate Account'];

    delete tasks;
}

To achieve the same thing with a trigger, I’d need to embed the business logic that determines whether the Validated field for the trigger accounts has been changed to true, then continue on with the code to locate the tasks and delete them.

This is less than ideal, as :

• business logic encapsulated in triggers is resistant to change. To alter the logic I need to update the trigger code in a sandbox and then deploy to production. 
• to allow an administrator to disable the trigger on demand I’d need to use something like a custom setting and add code to retrieve and check the value of the setting before continuing with the trigger code.
• Its a little less testable, as to test the trigger I have to insert a record, and there may be other trigger logic in place that affects the record, leading to more of an integration than unit test. With well-written triggers that delegate to helper classes this isn’t much of a downside, but testing the simple invocable method fits the definition of unit testing perfectly.

So would there be any reason to continue to use triggers once Spring 15 is live?  The answer is yes, for much the same reason that you might have used triggers to in place of workflow in the past - order of execution.  It’s still not possible (as far as I’ve been able to find out anyway!) to define the order in which processes for the same object will execute, whereas in triggers its straightforward to define the order that processing will take place as long as you adhere to the one trigger per object and action pattern.

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