On Sat, 12 Mar 2022 04:57:37 GMT, Michael Strauß <[email protected]> wrote:
> `Observable{List/Set/Map}Wrapper.retainAll/removeAll` can be optimized for
> some edge cases.
>
> 1. `removeAll(c)`:
> This is a no-op if 'c' is empty.
> For `ObservableListWrapper`, returning early skips an object allocation. For
> `ObservableSetWrapper` and `ObservableMapWrapper`, returning early prevents
> an enumeration of the entire collection.
>
> 2. `retainAll(c)`:
> This is a no-op if the backing collection is empty, or equivalent to
> `clear()` if `c` is empty.
>
> I've added some tests to verify the optimized behavior for each of the three
> classes.
Changes requested by jhendrikx (Committer).
modules/javafx.base/src/main/java/com/sun/javafx/collections/ObservableListWrapper.java
line 172:
> 170: @Override
> 171: public boolean removeAll(Collection<?> c) {
> 172: if (backingList.isEmpty() || c.isEmpty()) {
I think you should do an explicit `null` check here on `c` or swap the order of
these arguments so it always throws an NPE here if `c` is `null` as per
collection contract. If you don't, it will do this implicit `null` check just
after `beginChange`, and as I don't see a `try/finally` there to call
`endChange`, it would mean the wrapper / changeListBuilder gets in a bad state.
modules/javafx.base/src/main/java/com/sun/javafx/collections/ObservableListWrapper.java
line 195:
> 193: @Override
> 194: public boolean retainAll(Collection<?> c) {
> 195: if (backingList.isEmpty()) {
I think we need to check `c` for `null` here first to conform to the collection
contract.
modules/javafx.base/src/main/java/com/sun/javafx/collections/ObservableMapWrapper.java
line 328:
> 326:
> 327: private boolean removeRetain(Collection<?> c, boolean remove) {
> 328: if (c.isEmpty()) {
There is an implicit `null` check here, but it makes `removeAll` and
`retainAll` conform to the collection contract at least.
If you want to make this explicit (or document it), then this comment should be
applied to all the `removeRetain` methods.
-------------
PR Review: https://git.openjdk.org/jfx/pull/751#pullrequestreview-1365073384
PR Review Comment: https://git.openjdk.org/jfx/pull/751#discussion_r1153233153
PR Review Comment: https://git.openjdk.org/jfx/pull/751#discussion_r1153235221
PR Review Comment: https://git.openjdk.org/jfx/pull/751#discussion_r1153239642
