Paul King created GROOVY-12218:
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Summary: Complete fat-free (functional-interface) twins for the
array (`T[]`) forms of the GROOVY-12054 DGM methods
Key: GROOVY-12218
URL: https://issues.apache.org/jira/browse/GROOVY-12218
Project: Groovy
Issue Type: Sub-task
Reporter: Paul King
h3. Summary
GROOVY-12054 added {{java.util.function}} twins beside the Closure overloads of
the core higher-order DGM methods, but only in {{DefaultGroovyMethods}} — the
array-receiver forms in {{ArrayGroovyMethods}} were left with only their
{{Closure}} overloads. This completes the object-array ({{T[]}}) twins so array
receivers reach parity with the collection receivers. Each twin simply
delegates to the corresponding DGM {{Iterable}}/{{Iterator}} twin (already
shipped in GROOVY-12054) via {{ArrayIterable}}/{{ArrayIterator}}, following the
array pattern established in GROOVY-12215 / GROOVY-12216.
Already covered (not in scope): {{each}} on primitive arrays already has
{{Consumer}}/{{IntConsumer}}/etc. twins; {{collectEntries}} already has the
two-{{Function}} {{(keyTransform, valueTransform)}} forms; and the array forms
of
{{groupBy}}/{{collectMany}}/{{countBy}}/{{split}}/{{takeWhile}}/{{dropWhile}}
(GROOVY-12215) and {{inject}}/{{injectAll}} (GROOVY-12216) are done.
h3. Object-array twins to add
||Method (array form)||Count||Functional type||
|{{each(T[])}}|1|{{Consumer<? super T>}}|
|{{eachWithIndex(T[])}}|1|{{ObjIntConsumer<? super T>}}|
|{{collect(T[])}}, {{collect(T[], Collection collector)}}|2|{{Function<? super
E, ? extends T>}}|
|{{collectEntries(T[])}}, {{collectEntries(T[], Map collector)}}|2|{{Function<?
super E, ? extends Map.Entry<K, V>>}}|
|{{any(T[])}}|1|{{Predicate<? super T>}}|
|{{every(T[])}}|1|{{Predicate<? super T>}}|
|{{find(T[])}}|1|{{Predicate<? super T>}}|
|{{findAll(T[])}}|1|{{Predicate<? super T>}}|
|{{count(T[])}}|1|{{Predicate<? super T>}}|
Total: 11 object-array twins.
h3. Primitive-array predicates (decision needed)
{{any}}/{{every}}/{{count}} on primitive arrays currently take only a
{{Closure}}. The JDK provides
{{IntPredicate}}/{{LongPredicate}}/{{DoublePredicate}} but no
{{Byte}}/{{Char}}/{{Short}}/{{Float}} predicate, so only
{{int[]}}/{{long[]}}/{{double[]}} can be covered cleanly (3 receivers x 3
methods = 9 twins); the other four primitive types would be inconsistent
(widening to {{IntPredicate}} is ugly). *Options:* (a) add the 9 well-supported
primitive twins; (b) skip primitives for predicates and cover only {{T[]}}.
Recommendation: match how {{each}}'s primitive twins already exist only where a
JDK SAM fits — i.e. option (a) if primitive predicate ergonomics are wanted,
else (b).
h3. Exclusions
* {{eachWithIndex}} on primitive arrays — no JDK {{(primitive, int)}} SAM, so
only the {{T[]}} form ({{ObjIntConsumer}}) is clean.
* The {{@Incubating}} right-curry {{(BiXxx, param)}} array forms — GROOVY-12054
added these for {{Iterable}}/{{Iterator}} but not arrays; deferred as a
separate item.
h3. Conventions (per GROOVY-12054)
PECS wildcards; {{@since 6.0.0}}; javadoc {{<pre class="language-groovy
groovyTestCase">}} example cross-linking the {{Closure}} counterpart via
{{@link}}; plain SAM overloads (not {{@Incubating}}); bodies delegate to the
existing DGM twins.
h3. Compatibility
Existing closure/lambda call sites are unaffected; method references and typed
functional values select the new twins under {{@CompileStatic}} (GROOVY-12214).
The only check is an existing {{@CompileStatic}} call passing a literal
{{null}} to a currently-single-overload array method — rare and grep-checkable,
resolved with a cast if found.
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