Learning Monad Concepts and Async Programming Transition with Scala Future

This article is a tutorial for understanding Monad concepts by refactoring a shopping mall order history lookup feature from Blocking I/O to Non-Blocking I/O using Scala's Future type. It first points out the blocking issues arising from procedural code using Await.result, then progresses to asynchronous code by applying function composition using the flatMap operator, improving readability via for comprehension, and finally applying the async/await pattern using the scala-async library. Through this, it demonstrates that Future is a Monadic type following the rules of unit (wrapping a value) and bind(flatMap) (extracting and transforming it). However, it notes that Scala's Future does not satisfy the associativity law, so it should be described as 'Monadic' rather than a strict Monad, and also mentions the differences with Scalaz Task (which adheres to Monad laws), such as thread handling and performance.