On Tue, 11 Mar 2025 06:45:58 GMT, John Hendrikx <[email protected]> wrote:
>> This provides and uses a new implementation of `ExpressionHelper`, called
>> `ListenerManager` with improved semantics.
>>
>> See also #837 for a previous attempt which instead of triggering nested
>> emissions immediately (like this PR and `ExpressionHelper`) would wait until
>> the current emission finishes and then start a new (non-nested) emission.
>>
>> # Behavior
>>
>> |Listener...|ExpressionHelper|ListenerManager|
>> |---|---|---|
>> |Invocation Order|In order they were registered, invalidation listeners
>> always before change listeners|(unchanged)|
>> |Removal during Notification|All listeners present when notification started
>> are notified, but excluded for any nested changes|Listeners are removed
>> immediately regardless of nesting|
>> |Addition during Notification|Only listeners present when notification
>> started are notified, but included for any nested changes|New listeners are
>> never called during the current notification regardless of nesting|
>>
>> ## Nested notifications:
>>
>> | |ExpressionHelper|ListenerManager|
>> |---|---|---|
>> |Type|Depth first (call stack increases for each nested level)|(same)|
>> |# of Calls|Listeners * Depth (using incorrect old values)|Collapses nested
>> changes, skipping non-changes|
>> |Vetoing Possible?|No|Yes|
>> |Old Value correctness|Only for listeners called before listeners making
>> nested changes|Always|
>>
>> # Performance
>>
>> |Listener|ExpressionHelper|ListenerManager|
>> |---|---|---|
>> |Addition|Array based, append in empty slot, resize as needed|(same)|
>> |Removal|Array based, shift array, resize as needed|(same)|
>> |Addition during notification|Array is copied, removing collected
>> WeakListeners in the process|Appended when notification finishes|
>> |Removal during notification|As above|Entry is `null`ed (to avoid moving
>> elements in array that is being iterated)|
>> |Notification completion with changes|-|Null entries (and collected
>> WeakListeners) are removed|
>> |Notifying Invalidation Listeners|1 ns each|(same)|
>> |Notifying Change Listeners|1 ns each (*)|2-3 ns each|
>>
>> (*) a simple for loop is close to optimal, but unfortunately does not
>> provide correct old values
>>
>> # Memory Use
>>
>> Does not include alignment, and assumes a 32-bit VM or one that is using
>> compressed oops.
>>
>> |Listener|ExpressionHelper|ListenerManager|OldValueCaching ListenerManager|
>> |---|---|---|---|
>> |No Listeners|none|none|none|
>> |Single InvalidationListener|16 bytes overhead|none|none|
>> |Single ChangeListener|20 bytes overhead|none|16 bytes overhe...
>
> John Hendrikx has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Break up long lines of code
Finished the 2nd part of the implementation review. I didn't delve into the
logic of the listener management, but it looks sane :)
I'll review the tests as the final part.
modules/javafx.base/src/main/java/com/sun/javafx/binding/ListenerListBase.java
line 96:
> 94:
> 95: private static final ArrayManager<ListenerListBase,
> InvalidationListener> INVALIDATION_LISTENERS = new
> CompactingArrayManager<>(InvalidationListener.class) {
> 96: @Override
Empty line
modules/javafx.base/src/main/java/com/sun/javafx/binding/ListenerListBase.java
line 118:
> 116:
> 117: private static final ArrayManager<ListenerListBase, Object>
> CHANGE_LISTENERS = new CompactingArrayManager<>(Object.class) {
> 118: @Override
Empty line
modules/javafx.base/src/main/java/com/sun/javafx/binding/ListenerListBase.java
line 193:
> 191: else {
> 192: CHANGE_LISTENERS.add(this, listener1);
> 193: }
These can be
switch (listener1) {
case InvalidationListener il -> INVALIDATION_LISTENERS.add(this, il);
default -> CHANGE_LISTENERS.add(this, listener1);
}
but I don't know if it helps.
modules/javafx.base/src/main/java/com/sun/javafx/binding/ListenerListBase.java
line 422:
> 420:
> 421: private void assertInvalidationListenerIndex(int index) {
> 422: assert index < invalidationListenersCount : index + " >= " +
> invalidationListenersCount + ", results would be undefined";
Do we allow `assert` in production code? This will require to run the
application with `ea`. Or are these intended to be skipped in production and
are for tests only?
modules/javafx.base/src/main/java/javafx/beans/binding/ObjectBinding.java line
109:
> 107: public void addListener(ChangeListener<? super T> listener) {
> 108: observed = observed || listener != null;
> 109: LISTENER_MANAGER.addListener(this, (ChangeListener<Object>)
> listener);
This cast gives a warning.
modules/javafx.base/src/main/java/javafx/beans/property/ObjectPropertyBase.java
line 101:
> 99: @Override
> 100: public void addListener(ChangeListener<? super T> listener) {
> 101: LISTENER_MANAGER.addListener(this, (ChangeListener<Object>)
> listener);
This cast gives a warning.
modules/javafx.base/src/main/java/javafx/beans/property/ReadOnlyObjectPropertyBase.java
line 76:
> 74: @Override
> 75: public void addListener(ChangeListener<? super T> listener) {
> 76: LISTENER_MANAGER.addListener(this, (ChangeListener<Object>)
> listener);
Warning
modules/javafx.base/src/main/java/javafx/beans/value/ObservableValueBase.java
line 78:
> 76: @Override
> 77: public void addListener(ChangeListener<? super T> listener) {
> 78: LISTENER_MANAGER.addListener(this, (ChangeListener<Object>)
> listener);
Warning
-------------
PR Review: https://git.openjdk.org/jfx/pull/1081#pullrequestreview-2676530002
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990363868
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990363984
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990366337
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990370006
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990385681
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990385008
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990386512
PR Review Comment: https://git.openjdk.org/jfx/pull/1081#discussion_r1990387231
