io.simplesource.saga.action.async

Interface AsyncSpec.UndoFunction<A,D,O>

Enclosing class:

AsyncSpec<A,D,K,O,R>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public static interface AsyncSpec.UndoFunction<A,D,O>

The UndoFunction is a mechanism to take the result of the async invocation and turn it into an undo action command. This action command is passed back to the saga coordinator, and if the saga fails, this updated undo function will be invoked.

For example, if the async function calls an endpoint to book a hotel, the return value may include a booking reference. This booking reference is then used to create an undo action command that calls the corresponding cancel endpoint, passing in the booking reference.

Method Summary

Modifier and Type	Method and Description
Optional<UndoCommand<A>>	apply(D decodedInput, O output)

Method Detail

apply

Optional<UndoCommand<A>> apply(D decodedInput,
                               O output)

Parameters:

decodedInput - the decoded input type

output - the result of the async invocation

Returns:

an undo command, or Optional.empty() if no undo function is to be generated