On Mon, 27 Nov 2023 18:30:27 GMT, Andy Goryachev <[email protected]> wrote:
> Provide a public utility method for use by custom and core Nodes to simplify
> boilerplate around styleable properties as well as to save some memory.
>
>
> /**
> * Utility method which combines {@code CssMetaData} items in one
> immutable list.
> * <p>
> * The intended usage is to combine the parent and the child CSS meta
> data for
> * the purposes of {@code getClassCssMetaData()} method, see for example
> {@link Node#getClassCssMetaData()}.
> * <p>
> * Example:
> * <pre>
> * private static final List<CssMetaData<? extends Styleable, ?>>
> STYLEABLES = CssMetaData.combine(
> * <Parent>.getClassCssMetaData(),
> * STYLEABLE1,
> * STYLEABLE2
> * );
> * </pre>
> * This method returns an instance of {@link java.util.RandomAccess}
> interface.
> *
> * @param list the css metadata items, usually from the parent, must not
> be null
> * @param items the additional items
> * @return the immutable list containing all of the items
> *
> * @since 22
> */
> public static List<CssMetaData<? extends Styleable, ?>> combine(
> List<CssMetaData<? extends Styleable, ?>> list,
> CssMetaData<? extends Styleable, ?>... items)
>
>
> Problem(s):
>
> - the same less-than-optimal implementation is duplicated throughout the
> javafx code base which combines the parent and child styleable properties,
> using ArrayList wrapped in a Collections.unmodifiableList()
> - the capacity of underlying ArrayList might exceed the number of items,
> wasting memory
> - a potential exists for the custom component developer to inadvertently
> create a sub-standard implementation (i.e. return a List which does not
> implement RandomAccess interface), or forget to include parent's styleables.
>
> Non-Goals:
>
> - not redesigning the lazy initialization of STYLEABLES list
> - not changing the way styleables are enumerated in Nodes and Controls
> - not adding any new methods to JDK (collections)
>
> To Be Discussed:
>
> - it is not clear whether the order of styleables returned by <N extends
> Node>.getClassCssMetaData() is of any importance
> - the current spec for Node.getCssMetaData() specifies the return value as
> "The CssMetaData associated with this node, which may include the CssMetaData
> of its superclasses.", implying that it may or may not include. It is
> unclear whether it must include the parent's styleables (well, except the
> Node whose superclass is Object and thus has no styleable properties).
This pull request has been closed without being integrated.
-------------
PR: https://git.openjdk.org/jfx/pull/1296
