libgdx (Ashley Framework ECS) - What is the proper way of talking system to another system?

Question

System to System

Currently I'm developing CharacterSystem, GunSystem, BulletSystem using ashley framework. My problem is I dont know if this is the proper way of talking system to other system.

My CharacterSystem method onProcessEntity when the character attack is triggered I used getEngine().getSystem(GunSystem.class).trigger(true) and inside the GunSystem I have a method the Generate entity of a Bullet. While the BulletSystem handles the freeing of bodies, when outside the camera.

sub-question What is the proper way of creating Bullet class with ECS framework?

Answer 1

I never used Ashley as ECS but usually Systems should not communicate with each other.

Reason: When Systems would communicate they would not be independent of each other. Independent Systems allow you to freely add and remove them without having to worry the code breaks. The game logic probably breaks of course when a important Systems are missing.

Have a Factory (class) which does create the bullet entity. Then use the Factory in each System which can built new bullet entity.