The Observer pattern lets any object that implements the subscriber interface subscribe for event notifications in publisher objects. You can add the subscription mechanism to your buttons, letting the clients hook up their custom code via custom subscriber classes.

Observer pattern in C++. Full code example in C++ with detailed comments and explanation. Observer is a behavioral design pattern that allows some objects to notify other objects about changes in their state.

Observer pattern in Python. Full code example in Python with detailed comments and explanation. Observer is a behavioral design pattern that allows some objects to notify other objects about changes in their state.

Observer pattern in Java. Full code example in Java with detailed comments and explanation. Observer is a behavioral design pattern that allows some objects to notify other objects about changes in their state.

22 design patterns and 8 principles explained in depth. 409 well-structured, easy to read, jargon-free pages. 225 clear and helpful illustrations and diagrams. An archive with code examples in 11 languages. All devices supported: PDF/EPUB/MOBI/KFX formats. Learn more…

Mediator is a behavioral design pattern that lets you reduce chaotic dependencies between objects. The pattern restricts direct communications between the objects and forces them to collaborate only via a mediator object.

Chain of Responsibility is behavioral design pattern that allows passing request along the chain of potential handlers until one of them handles request. The pattern allows multiple objects to handle the request without coupling sender class to the concrete classes of the receivers.

22 design patterns and 8 principles explained in depth. 409 well-structured, easy to read, jargon-free pages. 225 clear and helpful illustrations and diagrams. An archive with code examples in 11 languages. All devices supported: PDF/EPUB/MOBI/KFX formats. Learn more…

Observer pattern in C#. Full code example in C# with detailed comments and explanation. Observer is a behavioral design pattern that allows some objects to notify other objects about changes in their state.

22 design patterns and 8 principles explained in depth. 409 well-structured, easy to read, jargon-free pages. 225 clear and helpful illustrations and diagrams. An archive with code examples in 11 languages. All devices supported: PDF/EPUB/MOBI/KFX formats. Learn more…