php-ddd / domain-driven-design Goto Github PK

We need to define an AbstractAggregateRoot in order to have some basic facilities:

• get the list of events triggered
• define some rules to apply Event

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One of the advantage of the event system is to give the ability to log every events that occurs in an application.

This should be built-in.
Furthermore, this will also give us a great example on how a bounded context looks like.

When it comes to change the state of an aggregate whether it's an addition, a deletion or a modification, it's probably a better idea not to have the same flow as when we read it.

The CQRS (command query responsibility segregation) design pattern is a way to fix that issue by defining a clear separation between the read and the write model.

We need to have this kind of feature inside our solution.

What should be included:

• an abstract Command object will give a draft of how to create a command,
• define what a CommandHandler should look like (class responsible of handling a command)
• create a CommandDispatcher (looks like an EventDispatcher but for command)

In Domain Driven Design, an event system allows to do some actions when something happened in an Aggregate.

Our event system should be able to:

• define a base Event named AbstractEvent
• define an EventDispatcher
  • centralize every listeners to have more control
• have some listeners
  • subscribe to as many events as needed
  • subscribe to an Interface of a parent class (allows to act on multiple event the same way)

Now we have a command system and an event system. They are separate but can definitely work together.

We need to provide a link between the two systems: a CommandEventDispatcher.
This will be able to start from a Command, handle it and then publish all the events that the command triggered.
We may also only want to publish an Event from this dispatcher.

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