Maestro.Aggregate.CommandHandler behaviour (Maestro v0.5.0)

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Simple behaviour for properly implementing command handlers the way that maestro expects. Its use is not required but is encouraged.

Summary

Types

command()
root()
uncommitted_event()

Callbacks

eval(root, command)

Command handlers in maestro should implement an eval function that expects to receive the current Root object complete with sequence number and aggregate ID and the incoming command. They should return a list of events or raise an error which can be used to short circuit the command processing cycle.

Types

command()

@type command() :: Maestro.Types.Command.t()

root()

@type root() :: Maestro.Aggregate.Root.t()

uncommitted_event()

@type uncommitted_event() :: Maestro.Types.Event.uncommitted()

Callbacks

eval(root, command)

@callback eval(root(), command()) :: [uncommitted_event()]

Command handlers in maestro should implement an eval function that expects to receive the current Root object complete with sequence number and aggregate ID and the incoming command. They should return a list of events or raise an error which can be used to short circuit the command processing cycle.