Engine Documentation

An Engine is an interface where the primary responsibility is running an Application. It is also required to provide an Emitter that is used to emit events pertaining to the Engine as well as keep track of what state it is in (idle, running, or crashed). In most use cases you would rarely, if ever, interact with the Engine directly outside of passing your Application instance to Engine::run so the rest of this documentation touches briefly on the process the default Engine implementation goes through and should be used as a baseline for your own Engine implementation if you choose to create your own.

Engine Running Process

1. Make sure the Engine is idle. Trying to start an Engine that is running or has crashed should result in an Exception.
2. Set an error handler on the Loop to ensure any exceptions that bubble up will be logged and passed to the Application's exception handler. Steps should be taken to ensure the Engine::SHUT_DOWN_EVENT still fires if possible.
3. Emit an Engine::START_UP_EVENT and ensure Application::loadPlugins is executed.
4. Execute the Application
5. Emit an Engine::SHUT_DOWN_EVENT

If you are implementing your own Engine instance it is highly recommended that you review the AmpEngine source for more detailed guidance.

{% include next_previous_article_nav.md previous_article_name="Applications" %}