Pattern Matching in Java 17 and Beyond

Pattern Matching is finding its way into Java, one step at a time, along three paths: patterns, switch improvements, sealed classes. This session will explore the recent history, current state, and future evolution of pattern matching in Java.

⎯⎯⎯⎯⎯⎯ Chapters ⎯⎯⎯⎯⎯⎯
00:00 Introduction
00:58 The Back Story
07:49 Type Patterns
10:22 Pattern Matching in Switch
13:18 Deconstruction Patterns
15:11 Guarded Patterns
17:52 Sealed Classes
20:16 Timeline
20:53 Plot Holes
21:26 Happy End
22:49 When should you use this?
25:47 Conclusion

⎯⎯⎯⎯⎯⎯ Resources ⎯⎯⎯⎯⎯⎯

Categories: #Java #Java17 #Development

In my view, this is an excellent and pedagogic presentation on the subject at hand. Thank you.

[JeremyChone]

Very well done and informative. Glad Java got its super switch. Been using similar patterns in Rust, and it does streamline the code pretty well (not to be abused obviously).

[bnayagrawal]

Should have used a different font like Consolas for code snippets, sometimes it was confusing whether it is a '(' open parenthesis or a '<' open angle bracket. Great video!

[MORETHANOVERGROWN]

The problem at @17:22 can be partially removed if Java adopts "as-patterns" in future versions. Search "Understanding the Haskell as-pattern" for more info. Essentially the as pattern lets you give a name to a variable while also matching its structure. Nice video and good to see what's coming :)

[wwhill]

Great explanation, a little twisted, but it worked. Thanks

[berndeckenfels]

BTW if sealed class is added in partial recompile the switch might not be exhaustive, so a „default: throw new is implied

[webtel]

Both new future and this video are excellent. I just wonder why you did not use term "exhaustive[ness]" when describing eliminating of default case for the switch with sealed classes/interfaces . Also does such switch need to have null case to be exhaustive?

[derrickheng]

Droolz @ deconstruction pattern <wishing hard>

[Redoranish]

I remember that in recent video Brian Goetz was talking about using pattern matching for Map::get to handle null values. Any example how it would work?

[quintesse]

6:37 "Math::evaluate"? Is that a typo or am I missing something here?

[Sackthing]

I know this is a coding video, but I just realized Duke looks like an Among Us character.

[berndeckenfels]

Let’s make that ugly with local assigns :) case Absolute(var n) && (v = eval(n)) < 0 -> v; (BTW in a pure functional Language it’s easy to cache the double eval, so it’s a more used method)

[billyean]

Copy from Scala. Please give credit to Scala

[HoDx]

ah, java is trying to copy scala now :)