3 ms·

final RingBuffer<String> ringBuffer = new RingBuffer<>(String.class, capacity); Why does the constructor need the Class<?> parameter?

o11c 2y ago
That's about the least-bad thing about the code here - it's a workaround for the fact that Java lacks runtime support for generics. Other than its indirect use in `copy` (which in Java normally takes the parameter itself), it's probably not actually necessary here since you could just use `Object[]`? But I don't spend enough time in Java (thankfully) so I'm not sure if there are intricacies involving the runtime overhead of casting.
jcrites 2y ago
Looking at the source, I don't think there's an actual need for the constructor to take a `Class<T>` type. It's used internally to initialize an array [1]: this.entries = (T[]) Array.newInstance(type, capacity); However, I think this alternative would work equally well, and would not require a `Class<T>` parameter: this.entries = (T[]) new Object[capacity]; There are some other choices in the library that I don't understand, such as the choice to have a static constructor with this signature: public static RingBuffer<Object> create(final int capacity) { return create(capacity, false); } This returns the type `RingBuffer<Object>`, which isn't as useful as it could be; with appropriate idiomatic use of generics it could return a `RingBuffer<T>`: public static <T> RingBuffer<T> create(final int capacity, final boolean orderedReads) { return new RingBuffer<>(capacity, orderedReads); } It's possible that this code was written by someone who is still learning idiomatic Java style, or effective use of generics. I'm also curious about the choice to have `get()` return `null`. I think I'd rather have seen this modeled with `Optional`. My preferred style when writing Java code is to employ non-nullable references wherever possible (though the return from `get()` is marked `@Nullable` at least). [1] https://github.com/evolvedbinary/j8cu/blob/94d64cfc0ec49a34002aae136b6f080c10976748/src/main/java/com/evolvedbinary/j8cu/RingBuffer.java#L115C9-L115C64 https://github.com/evolvedbinary/j8cu/blob/94d64cfc0ec49a340...
IncreasePosts 2y ago
Line 115: this.entries = (T[]) Array.newInstance(type, capacity) You can't just say new T[capacity] in java.
- jcrites 2y ago
  True, but you can say `new Object[capacity]` and cast it to type `T[]`.

o11c 2y ago

That's about the least-bad thing about the code here - it's a workaround for the fact that Java lacks runtime support for generics. Other than its indirect use in `copy` (which in Java normally takes the parameter itself), it's probably not actually necessary here since you could just use `Object[]`? But I don't spend enough time in Java (thankfully) so I'm not sure if there are intricacies involving the runtime overhead of casting.

jcrites 2y ago

Looking at the source, I don't think there's an actual need for the constructor to take a `Class<T>` type. It's used internally to initialize an array [1]: this.entries = (T[]) Array.newInstance(type, capacity); However, I think this alternative would work equally well, and would not require a `Class<T>` parameter: this.entries = (T[]) new Object[capacity]; There are some other choices in the library that I don't understand, such as the choice to have a static constructor with this signature: public static RingBuffer<Object> create(final int capacity) { return create(capacity, false); } This returns the type `RingBuffer<Object>`, which isn't as useful as it could be; with appropriate idiomatic use of generics it could return a `RingBuffer<T>`: public static <T> RingBuffer<T> create(final int capacity, final boolean orderedReads) { return new RingBuffer<>(capacity, orderedReads); } It's possible that this code was written by someone who is still learning idiomatic Java style, or effective use of generics. I'm also curious about the choice to have `get()` return `null`. I think I'd rather have seen this modeled with `Optional`. My preferred style when writing Java code is to employ non-nullable references wherever possible (though the return from `get()` is marked `@Nullable` at least). [1] https://github.com/evolvedbinary/j8cu/blob/94d64cfc0ec49a34002aae136b6f080c10976748/src/main/java/com/evolvedbinary/j8cu/RingBuffer.java#L115C9-L115C64 https://github.com/evolvedbinary/j8cu/blob/94d64cfc0ec49a340...

IncreasePosts 2y ago

Line 115: this.entries = (T[]) Array.newInstance(type, capacity) You can't just say new T[capacity] in java.

jcrites 2y ago
True, but you can say `new Object[capacity]` and cast it to type `T[]`.