RFR: 8091429: ObservableList<E>#replaceRange(int from, int to, Collection<? extends E> col) [v2]

[Kevin Rushforth]

On Mon, 20 Oct 2025 05:06:20 GMT, John Hendrikx <jhendrikx at openjdk.org> wrote:

>> This PR implements a new default method on `ObservableList` to be able to replace elements within a specified range.
>> 
>> Justification for this change is to allow an `ObservableList` to be bulk modified resulting in a single `ListChangeListener` call back.  In this way the callbacks don't observe the list changing its size from S to S-X back to S again(*). Currently the only way to bulk replace a range of items is to remove X items then add X items, resulting in two listener callbacks in between which the size of the list can be observed to change.
>> 
>> The other alternative is to call `set` individually for each item, which results in many change notifications.
>> 
>> With the addition of this PR, and the changes in `ModifiableObservableListBase`, replacing a range of items becomes a single change callback.
>> 
>> (*) The list may indeed change size still as plain `List` does not have `setAll` operations; size listeners may observe this, but it will no longer be observable from a `ListChangeListener` due to multiple separate callbacks.
>
> John Hendrikx has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Fix test
>  - Rename setAll to replaceRange and removed superfluous method

Looks good. I left a question as to whether a couple additional tests might be useful.

modules/javafx.base/src/test/java/test/javafx/collections/ModifiableObservableListBaseTest.java line 94:

> 92:         @Test
> 93:         void shouldReplaceElementsAtGivenRange() {
> 94:             assertTrue(list.replaceRange(1, 3, List.of("B", "C", "D")));

Would additional tests be useful?

* Replace a sub-range in the middle (so both beginning and end are kept)
* Replace a sub-range with fewer elements than are removed (the existing test checks the case of more elements added than removed)

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Marked as reviewed by kcr (Lead).

PR Review: https://git.openjdk.org/jfx/pull/1937#pullrequestreview-3418762471
PR Review Comment: https://git.openjdk.org/jfx/pull/1937#discussion_r2492152669