QueueableProcess

STATUS: ACTIVE

This class provides a way for developers to create a process of Queueable classes. This implementation facilitates the handoff of data into the overarching process and from one process step to the next. While functionally similar to the way a 'Promise' pattern allows you chain async methods together. However, a true Promise pattern resolves itself, one way or another, within the same transaction. Therefore, this is not a true Promise pattern, but an elegant way to logically chain Salesforce Queueables together. As a Developer, you'll need to extend this class, implementing the necessary execute method. Your execute method will be invoked asynchronously as part of a Queueable. You can then chain additional Queueables together using the then method provided by this class.
As each 'step' of the chain is completed the transaction finalizer will be constructed with the remaining steps and any passthrough data you specify. Passthrough data allows you to pass data between steps.

Implemented types

Queueable , Database.AllowsCallouts

Constructors

protected QueueableProcess()

SUPPRESSWARNINGS

this is a constructor that is used by extension classes;

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Fields

public dataPassthrough → Object

private defaultHandleExceptionCalled → Boolean

TESTVISIBLE

public finalizerContextHistory → List<FinalizerContext>

public processSteps → List<QueueableProcess>

public queueableContextHistory → List<QueueableContext>

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Methods

public QueueableProcess then(QueueableProcess toAdd)

This method provides a syntactic sugar for adding a new QueueableProcess to the chain.

Parameters

Param	Description
toAdd	An instance of a class that extends this QueueableProcess class and implements the execute method.

Returns

Type	Description
QueueableProcess	Returns a Queueable Process instance that can be used to chain additional QueueableProcess instances.

public Id start()

This method starts the QueueableProcess chain. It's the entry point for the process.

Returns

Type	Description
Id	Id - Id of the Enqueued job.

public Id start(Object initialPassthrough)

This method starts the QueueableProcess chain. It's the entry point for the process.

Parameters

Param	Description
initialPassthrough	Object - this is the initial passthrough data that will be passed to the first QueueableProcess in the chain.

Returns

Type	Description
Id	Id - Id of the Enqueued job.

public void execute()

This must be implemented by extending classes. Developers - implement this method with the work you want executed asynchronously.

public void handleException(Exception incomingException)

this is a default implementation of an handleError method. It's called by the finalizer if the developer doesn't implement their own handleError method. Developers can write per-step error handling by implementing their own handleError method as public override void handleError(Exception incomingException)

Parameters

Param	Description
incomingException	Exception - the exception that was thrown during execution.

public void execute(QueueableContext context)

This is required by the Queueable interface. It's the essence of how the QueueableProcess pattern is implemented in Apex.

Parameters

Param	Description
context	QueueableContext - dependency injected by Salesforce at execution time.

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