Designing functional and fluent API: example of the Visitor Pattern
summary
Live coding shows an implementation of the Visitor pattern in Java that avoids mutating state or changing the object model by using lambdas, a Map<Class,Function> registry, and type-safe generics with a few explicit casts. It builds a fluent API (builder/initializer, chained for(type).execute(fn) calls) and a visitable factory that maps functions over an object graph, then reduces results with Collector + Stream reduction to produce joined strings or lists. The example compiles and runs, producing expected concatenated strings and lists.
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chapters (8)
- 0:00Start
- 1:29Why the Visitor Pattern
- 17:17Composition over Inheritance
- 21:58Visitor Builder
- 22:57Create a Default Method on the Visitor Builder
- 26:00Create an Init Method
- 47:52Make Visible Default Method
- 49:46Accept Method
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