On Sat, 5 Sep 2026 12:19:38 GMT, Michael Strauß <[email protected]> wrote:

>> Implementation of [enhanced property 
>> metadata](https://gist.github.com/mstr2/2fec0303fc440b8eaeb126befc76eb5c).
>> 
>> ### New API
>> This PR includes the following API additions:
>> 
>> 1. `ReadOnlyProperty.getDeclaringClass()` and its default implementation.
>> 2. The `javafx.beans.property.AttachedProperty` interface.
>> 3. New constructors for all `Simple<*>Property` and `ReadOnly<*>Wrapper` 
>> classes, accepting the declaring class of the property.
>> 
>> The declaring class is stored in a new field in the `Simple<*>Property` 
>> classes. If a legacy constructor is used that doesn't specify the declaring 
>> class, the `ReadOnlyProperty.getDeclaringClass()` default implementation is 
>> called the first time the `Simple<*>Property.getDeclaringClass()` method is 
>> called, and its result is stored for future retrieval.
>> 
>> ### Testing
>> For testing, this PR also includes the 
>> `test.util.property.PropertyMetadataVerifier` tool. It systematically tests 
>> all public and protected properties of a class, and ensures conformance to 
>> the following rules:
>> * `ReadOnlyProperty.getBean()` returns the object instance of the enclosing 
>> class, or the target object instance if the property is an attached property.
>> *  `ReadOnlyProperty.getName()` returns the name of the property, which must 
>> correspond to the name of the property getter (excluding the word 
>> "Property").
>> * `ReadOnlyProperty.getDeclaringClass()` returns the enclosing class of the 
>> property getter.
>> * The declaring class of a `Simple<*>Property` or `ReadOnly<*>Wrapper` must 
>> be specified in the constructor, not resolved at runtime.
>> * `getBean()`, `getName()`, and `getDeclaringClass()` must not be overridden 
>> in subclasses of `Simple<*>Property` or `ReadOnly<*>Wrapper`.
>> * An instance property does not implement `AttachedProperty`.
>> * An instance property has a parameterless property getter.
>> * An attached property implements `AttachedProperty`.
>> * An attached property has a static single-argument property getter that 
>> accepts the target object.
>> * `AttachedProperty.getTargetClass()` returns the class of the single 
>> parameter of the static property getter.
>> * A property getter does not return an instance of `ReadOnly<*>Wrapper`, it 
>> returns the result of calling `ReadOnly<*>Wrapper.getReadOnlyProperty()`.
>> 
>> Many properties in existing JavaFX classes violate the 
>> `PropertyMetadataVerifier` rules in some way or shape. This PR won't address 
>> these issues, this will be done in a future cleanup PR.
>> 
>> ---------
>> - [x] I confirm...
>
> Michael Strauß has updated the pull request with a new target base due to a 
> merge or a rebase. The pull request now contains 12 commits:
> 
>  - add ctor overloads to SimpleStyleable* properties
>  - Merge branch 'master' into feature/property-metadata
>  - revert
>  - remove test
>  - Update javadocs
>  - Merge branch 'master' into feature/property-metadata
>    
>    # Conflicts:
>    #  modules/javafx.graphics/src/main/java/javafx/scene/layout/HeaderBar.java
>  - Merge branch 'master' into feature/property-metadata
>    
>    # Conflicts:
>    #  modules/javafx.graphics/src/test/addExports
>  - Merge branch 'master' into feature/property-metadata
>  - review changes
>  - ReadOnlyProperty.getDeclaringClass() tests
>  - ... and 2 more: https://git.openjdk.org/jfx/compare/6670f897...78a38fa8

beside one thing where I'm curious about other opinions, I think this a good 
way forward.

modules/javafx.base/src/main/java/javafx/beans/property/ReadOnlyProperty.java 
line 102:

> 100:                         && 
> ReadOnlyProperty.class.isAssignableFrom(method.getReturnType())) {
> 101:                     return beanClass;
> 102:                 }

I was still wondering if it might make sense to log a `warning` or just an 
`info` that this is really is a fallback implementation and developers should 
rather override this / set the declaring `Class` instead.

All opinions welcome.

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

PR Review: https://git.openjdk.org/jfx/pull/2015#pullrequestreview-5121388170
PR Review Comment: https://git.openjdk.org/jfx/pull/2015#discussion_r3940739013

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