Observer
Design Pattern UML Examples - Software Ideas Modeler
https://gyazo.com/8f2a69d59b9c0a2744ce3fcbb9a38df6
https://gyazo.com/3ee6e55aec760240bb859619274f6f3c
凡例:
class の依存関係の種類
https://gyazo.com/4c41cc9ef95562bb48b1cec61aa79a49