Observer Design Pattern
Understand how the Observer design pattern works in Kotlin by managing publishers and subscribers using higher-order functions. Learn to implement dynamic runtime subscription and unsubscription along with effective state communication through data classes. This lesson equips you with practical skills to apply Observer pattern principles in Kotlin, enhancing your ability to build flexible, reactive software components.
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So, what is the Observer design pattern all about? We have one publisher, which may also be called a subject, that may have many subscribers, also known as observers. Each time something interesting happens with the publisher, all of its subscribers should be updated.
This may look a lot like the Mediator design pattern, but there’s a twist. Subscribers should be able to register or unregister themselves at runtime.
In the classical implementation, all subscribers (or observers) need to implement a particular interface for the publisher to update them. But since Kotlin has higher-order functions, we can omit this part. The publisher will still have to provide a means for observers to be able to subscribe and unsubscribe.
This may ...