RFR: 8283063: Optimize Observable{List/Set/Map}Wrapper.retainAll/removeAll

[yosbits]

On Sat, 12 Mar 2022 04:57:37 GMT, Michael Strauß <mstrauss at openjdk.org> 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.

This is an equivalent change that partially includes the fix I proposed in #305.
It is good to apply it to Map / Set.

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PR: https://git.openjdk.java.net/jfx/pull/751