> Introduction
> 
> There is a number of places where various listeners (strong as well as weak) 
> are added, to be later disconnected in one go. For example, Skin 
> implementations use dispose() method to clean up the listeners installed in 
> the corresponding Control (sometimes using 
> LambdaMultiplePropertyChangeListenerHandler class).
> 
> This pattern is also used by app developers, but there is no public utility 
> class to do that, so every one must invent their own, see for instance
> https://github.com/andy-goryachev/FxTextEditor/blob/master/src/goryachev/fx/FxDisconnector.java
> 
> Proposal
> 
> It might be beneficial to create a class (ListenerHelper, feel free to 
> suggest a better name) which:
> 
> - provides convenient methods like addChangeListener, 
> addInvalidationListener, addWeakChangeListener, etc.
> - keeps track of the listeners and the corresponding ObservableValues
> - provides a single disconnect() method to remove all the listeners in one go.
> - optionally, it should be possible to add a lambda (Runnable) to a group of 
> properties
> - optionally, there should be a boolean flag to fire the lambda immediately
> - strongly suggest implementing an IDisconnectable functional interface with 
> a single disconnect() method
> 
> Make it Public Later
> 
> Initially, I think we could place the new class in package 
> com.sun.javafx.scene.control; to be made publicly accessible later.
> 
> Where It Will Be Useful
> 
> [JDK-8294589](https://bugs.openjdk.org/browse/JDK-8294589) "MenuBarSkin: 
> memory leak when changing skin"
> and other skins, as a replacement for 
> LambdaMultiplePropertyChangeListenerHandler.
> 
> https://github.com/openjdk/jfx/pull/908#:~:text=19%20hours%20ago-,8295175%3A%20SplitPaneSkinSkin%3A%20memory%20leak%20when%20changing%20skin%20%23911,-Draft
> 
> https://github.com/openjdk/jfx/pull/914

Andy Goryachev has updated the pull request incrementally with one additional 
commit since the last revision:

  Revert "8294809: removed weak listeners support"
  
  This reverts commit 2df4a85db638d76cacaf6c54ba669cdb3dd91a18.

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/908/files
  - new: https://git.openjdk.org/jfx/pull/908/files/2df4a85d..c518cbf9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=908&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=908&range=01-02

  Stats: 644 lines in 2 files changed: 643 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/908.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/908/head:pull/908

PR: https://git.openjdk.org/jfx/pull/908

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