I've been a fan of the "newtype" pattern for a while, especially as it applies in Rust. I'm really interested in applying this in my Java projects to avoid using generic types like `String` or `int` everywhere. I've been hesitant because I thought there would be significant runtime overhead, particularly from wrapping every ID string in our codebase. However, with the proposed value classes from the JEP 401, I wonder if I could implement this pattern without impacting performance. Will using value records like `value record FooID(String);` and `value record BarID(String);` be just as efficient as using plain strings? Should I reconsider using regular records or even traditional classes instead? I've always thought that wrapping each ID would add excessive heap allocations, but I'm not sure if that's the case. I'd love to hear your experiences and thoughts on this!
5 Answers
Definitely give it a shot! Using types like `Duration` rather than generic numbers can clarify your intent. It'll help avoid confusion over what measurement you're dealing with and keep your codebase clean. You might worry about performance, but the JVM handles inlining pretty well, even now. Don't just guess—measure if performance is really suffering!
Agreed! Too many hours wasted on conversion errors between units just because we used plain numbers. Stick to types!
Your notion of the newtype pattern mirrors the idea of avoiding "primitive obsession." Strongly typed APIs with distinct types can prevent misuse and clearly convey intent. Using value classes in your scenario is a great step towards that! Performance-wise, they're expected to behave similarly to primitives, so go for it!
Absolutely! Writing cleaner code with defined types will pay off in clarity. As we get more features with value classes, stronger typing should become the standard.
Just a heads up, if you're treating these new types like primitive types in equality checks, keep in mind that behavior can differ. Make sure you understand how Java handles these comparisons as you implement.
Great point! It's crucial to know that `==` can behave unexpectedly for object comparisons. Understanding this will help prevent bugs down the line.
Value classes are definitely what you need! They can act as lightweight wrappers around your existing types with far fewer allocations and better optimization opportunities. Going forward, this should be the way to type safety in Java!
Yes! Java needs to embrace these patterns more for safer APIs. Plus, the potential for cleaner semantics is just a bonus.
You are right to consider performance! But remember, only a few allocations can impact performance noticeably. If IDs are created and used temporarily, the impact of those wrappers might be negligible due to escape analysis optimizations in the JVM. Benchmarks are essential!
Exactly! You might find that the overhead is much less than you think. Just make sure to test it in your specific case.
Right? Using types for units really minimizes mistakes and clears up code. It’s much easier to keep track of what you're working with, which makes maintenance a lot simpler.