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Merged
ktoso merged 2 commits into from
Apr 17, 2026
Merged

jextract/jni: Move enum case classes inside the Case interface #709

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bd224aa
Move case classes into `Case` interface block.
sidepelican Apr 17, 2026
0453939
Fix compile error in JNI benchmark code
sidepelican Apr 17, 2026
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10 changes: 10 additions & 0 deletions Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/Enums.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -21,3 +21,13 @@ public enum EnumWithBacktick {
case `let`
case `default`
}

public enum EnumWithCaseNameValue {
case success(Success)
public struct Success {
public init(message: String) {
self.message = message
}
public var message: String
}
}
6 changes: 3 additions & 3 deletions Samples/SwiftJavaExtractJNISampleApp/src/jmh/java/com/example/swift/EnumBenchmark.java
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Expand Up @@ -51,10 +51,10 @@ public void afterAll() {
}

@Benchmark
public Vehicle.Motorbike getAssociatedValues(BenchmarkState state, Blackhole bh) {
Vehicle.Motorbike motorbike = state.vehicle.getAsMotorbike().orElseThrow();
public Vehicle.Case.Motorbike getAssociatedValues(BenchmarkState state, Blackhole bh) {
Vehicle.Case.Motorbike motorbike = state.vehicle.getAsMotorbike().orElseThrow();
bh.consume(motorbike.arg0());
bh.consume(motorbike.horsePower());
return motorbike;
}
}
}
15 changes: 14 additions & 1 deletion Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/EnumTest.java
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Expand Up @@ -24,7 +24,7 @@ public class EnumTest {
void enumWithValueCases() {
try (var arena = SwiftArena.ofConfined()) {
EnumWithValueCases e = EnumWithValueCases.firstCase(48, arena);
EnumWithValueCases.FirstCase c = (EnumWithValueCases.FirstCase) e.getCase();
EnumWithValueCases.Case.FirstCase c = (EnumWithValueCases.Case.FirstCase) e.getCase();
assertNotNull(c);
}
}
Expand All @@ -36,4 +36,17 @@ void enumWithBacktick() {
assertTrue(e.getAsDefault().isPresent());
}
}

@Test
void enumWithCaseNameValue() {
try (var arena = SwiftArena.ofConfined()) {
var success = EnumWithCaseNameValue.Success.init("ok", arena);
EnumWithCaseNameValue e = EnumWithCaseNameValue.success(success, arena);

switch (e.getCase(arena)) {
case EnumWithCaseNameValue.Case.Success(var s):
assertEquals("ok", s.getMessage());
}
}
}
}
4 changes: 2 additions & 2 deletions Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/GenericTypeTest.java
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Expand Up @@ -65,8 +65,8 @@ void genericEnum() {
try (var arena = SwiftArena.ofConfined()) {
GenericEnum<Long> value = MySwiftLibrary.makeIntGenericEnum(arena);
switch (value.getCase()) {
case GenericEnum.Foo _ -> assertTrue(value.getAsFoo().isPresent());
case GenericEnum.Bar _ -> assertTrue(value.getAsBar().isPresent());
case GenericEnum.Case.Foo _ -> assertTrue(value.getAsFoo().isPresent());
case GenericEnum.Case.Bar _ -> assertTrue(value.getAsBar().isPresent());
}
}
}
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28 changes: 14 additions & 14 deletions Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/VehicleEnumTest.java
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Expand Up @@ -92,7 +92,7 @@ void upgrade() {
void getAsBicycle() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.bicycle(arena);
Vehicle.Bicycle bicycle = vehicle.getAsBicycle().orElseThrow();
Vehicle.Case.Bicycle bicycle = vehicle.getAsBicycle().orElseThrow();
assertNotNull(bicycle);
}
}
Expand All @@ -101,7 +101,7 @@ void getAsBicycle() {
void getAsCar() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.car("BMW", Optional.empty(), arena);
Vehicle.Car car = vehicle.getAsCar().orElseThrow();
Vehicle.Case.Car car = vehicle.getAsCar().orElseThrow();
assertEquals("BMW", car.arg0());

vehicle = Vehicle.car("BMW", Optional.of("Long trailer"), arena);
Expand All @@ -114,7 +114,7 @@ void getAsCar() {
void getAsMotorbike() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.motorbike("Yamaha", 750, OptionalInt.empty(), arena);
Vehicle.Motorbike motorbike = vehicle.getAsMotorbike().orElseThrow();
Vehicle.Case.Motorbike motorbike = vehicle.getAsMotorbike().orElseThrow();
assertEquals("Yamaha", motorbike.arg0());
assertEquals(750, motorbike.horsePower());
assertEquals(OptionalInt.empty(), motorbike.helmets());
Expand All @@ -129,7 +129,7 @@ void getAsMotorbike() {
void getAsTransformer() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.transformer(Vehicle.bicycle(arena), Vehicle.car("BMW", Optional.empty(), arena), arena);
Vehicle.Transformer transformer = vehicle.getAsTransformer(arena).orElseThrow();
Vehicle.Case.Transformer transformer = vehicle.getAsTransformer(arena).orElseThrow();
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@ktoso ktoso Apr 17, 2026

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The alternative would be to Vehicle.TransformerCase or Vehicle.$Transformer hm... The $ in the name is not ideal perhaps, we usually tell folks that things with $ in the name are "not for them" but the Case sufficient could work without the additional nesting...

WDYT, any opinions @madsodgaard ?

assertTrue(transformer.front().getAsBicycle().isPresent());
assertEquals("BMW", transformer.back().getAsCar().orElseThrow().arg0());
}
Expand All @@ -139,7 +139,7 @@ void getAsTransformer() {
void getAsBoat() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.boat(OptionalInt.of(10), Optional.of((short) 1), arena);
Vehicle.Boat boat = vehicle.getAsBoat().orElseThrow();
Vehicle.Case.Boat boat = vehicle.getAsBoat().orElseThrow();
assertEquals(OptionalInt.of(10), boat.passengers());
assertEquals(Optional.of((short) 1), boat.length());
}
Expand All @@ -149,10 +149,10 @@ void getAsBoat() {
void associatedValuesAreCopied() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.car("BMW", Optional.empty(), arena);
Vehicle.Car car = vehicle.getAsCar().orElseThrow();
Vehicle.Case.Car car = vehicle.getAsCar().orElseThrow();
assertEquals("BMW", car.arg0());
vehicle.upgrade();
Vehicle.Motorbike motorbike = vehicle.getAsMotorbike().orElseThrow();
Vehicle.Case.Motorbike motorbike = vehicle.getAsMotorbike().orElseThrow();
assertNotNull(motorbike);
// Motorbike should still remain
assertEquals("BMW", car.arg0());
Expand All @@ -174,7 +174,7 @@ void getCase() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.bicycle(arena);
Vehicle.Case caseElement = vehicle.getCase(arena);
assertInstanceOf(Vehicle.Bicycle.class, caseElement);
assertInstanceOf(Vehicle.Case.Bicycle.class, caseElement);
}
}

Expand All @@ -183,23 +183,23 @@ void switchGetCase() {
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.car("BMW", Optional.empty(), arena);
switch (vehicle.getCase(arena)) {
case Vehicle.Bicycle b:
case Vehicle.Case.Bicycle b:
fail("Was bicycle");
break;
case Vehicle.Car car:
case Vehicle.Case.Car car:
assertEquals("BMW", car.arg0());
break;
case Vehicle.Motorbike motorbike:
case Vehicle.Case.Motorbike motorbike:
fail("Was motorbike");
break;
case Vehicle.Transformer transformer:
case Vehicle.Case.Transformer transformer:
fail("Was transformer");
break;
case Vehicle.Boat b:
case Vehicle.Case.Boat b:
fail("Was boat");
break;
}
}
}

}
}
43 changes: 24 additions & 19 deletions Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaBindingsPrinting.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -497,7 +497,30 @@ extension JNISwift2JavaGenerator {
return
}

printer.print("public sealed interface Case {}")
printer.printBraceBlock("public sealed interface Case") { printer in
for enumCase in decl.cases {
guard let translatedCase = self.translatedEnumCase(for: enumCase) else {
continue
}

let members = translatedCase.translatedValues.map {
$0.parameter.renderParameter()
}
let caseName = enumCase.name.firstCharacterUppercased

// Print record
printer.printBraceBlock("record \(caseName)(\(members.joined(separator: ", "))) implements Case") {
printer in
let nativeParameters = zip(translatedCase.translatedValues, translatedCase.parameterConversions).map {
value,
conversion in
"\(conversion.native.javaType) \(value.parameter.name)"
}

printer.print("record _NativeParameters(\(nativeParameters.joined(separator: ", "))) {}")
}
}
}
printer.println()

let requiresSwiftArena = decl.cases.compactMap {
Expand Down Expand Up @@ -539,24 +562,6 @@ extension JNISwift2JavaGenerator {
return
}

let members = translatedCase.translatedValues.map {
$0.parameter.renderParameter()
}

let caseName = enumCase.name.firstCharacterUppercased

// Print record
printer.printBraceBlock("public record \(caseName)(\(members.joined(separator: ", "))) implements Case") {
printer in
let nativeParameters = zip(translatedCase.translatedValues, translatedCase.parameterConversions).map {
value,
conversion in
"\(conversion.native.javaType) \(value.parameter.name)"
}

printer.print("record _NativeParameters(\(nativeParameters.joined(separator: ", "))) {}")
}

self.printJavaBindingWrapperMethod(&printer, translatedCase.getAsCaseFunction, skipMethodBody: false)
printer.println()
}
Expand Down
7 changes: 4 additions & 3 deletions Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaTranslation.swift
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Expand Up @@ -129,7 +129,8 @@ extension JNISwift2JavaGenerator {

let caseName = enumCase.name.firstCharacterUppercased
let enumName = enumCase.enumType.nominalTypeDecl.name
let nativeParametersType = JavaType.class(package: nil, name: "\(caseName)._NativeParameters")
let caseType = JavaType.class(package: nil, name: "Case.\(caseName)")
let nativeParametersType = JavaType.class(package: nil, name: "Case.\(caseName)._NativeParameters")
let getAsCaseName = "getAs\(caseName)"
// If the case has no parameters, we can skip the native call.
let constructRecordConversion = JavaNativeConversionStep.method(
Expand All @@ -138,7 +139,7 @@ extension JNISwift2JavaGenerator {
arguments: [
.constructJavaClass(
.commaSeparated(conversions.map(\.translated.conversion)),
.class(package: nil, name: caseName),
caseType,
)
],
)
Expand Down Expand Up @@ -179,7 +180,7 @@ extension JNISwift2JavaGenerator {
),
parameters: [],
resultType: TranslatedResult(
javaType: .class(package: nil, name: "Optional", typeParameters: [.class(package: nil, name: caseName)]),
javaType: .optional(caseType),
outParameters: conversions.flatMap(\.translated.outParameters),
conversion: enumCase.parameters.isEmpty
? constructRecordConversion
Expand Down
2 changes: 1 addition & 1 deletion Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+SwiftThunkPrinting.swift
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Expand Up @@ -409,7 +409,7 @@ extension JNISwift2JavaGenerator {
}

private func renderEnumCaseCacheInit(_ enumCase: TranslatedEnumCase) -> String {
let nativeParametersClassName = "\(enumCase.enumName)$\(enumCase.name)$_NativeParameters"
let nativeParametersClassName = "\(enumCase.enumName)$Case$\(enumCase.name)$_NativeParameters"
let methodSignature = MethodSignature(
resultType: .void,
parameterTypes: enumCase.parameterConversions.map(\.native.javaType),
Expand Down
5 changes: 5 additions & 0 deletions Sources/JExtractSwiftLib/JavaTypes/JavaType+JDK.swift
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Expand Up @@ -45,6 +45,11 @@ extension JavaType {
.class(package: "java.lang", name: "Object")
}

/// The description of the type java.util.Optional.
static func optional(_ T: JavaType) -> JavaType {
.class(package: "java.util", name: "Optional", typeParameters: [T])
}
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@ktoso ktoso Apr 17, 2026

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nice


/// The description of the type java.util.concurrent.CompletableFuture<T>
static func completableFuture(_ T: JavaType) -> JavaType {
.class(package: "java.util.concurrent", name: "CompletableFuture", typeParameters: [T.boxedType])
Expand Down
24 changes: 12 additions & 12 deletions Sources/SwiftJavaDocumentation/Documentation.docc/SupportedFeatures.md
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Expand Up @@ -208,7 +208,7 @@ You can then instantiate a case of `Vehicle` by using one of the static methods:
```java
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.car("BMW", arena);
Optional<Vehicle.Car> car = vehicle.getAsCar();
Optional<Vehicle.Case.Car> car = vehicle.getAsCar();
assertEquals("BMW", car.orElseThrow().arg0());
}
```
Expand All @@ -217,10 +217,10 @@ As you can see above, to access the associated values of a case you can call one
```java
try (var arena = SwiftArena.ofConfined()) {
Vehicle vehicle = Vehicle.bycicle("My Brand", arena);
Optional<Vehicle.Car> car = vehicle.getAsCar();
Optional<Vehicle.Case.Car> car = vehicle.getAsCar();
assertFalse(car.isPresent());

Optional<Vehicle.Bicycle> bicycle = vehicle.getAsBicycle();
Optional<Vehicle.Case.Bicycle> bicycle = vehicle.getAsBicycle();
assertEquals("My Brand", bicycle.orElseThrow().maker());
}
```
Expand All @@ -246,10 +246,10 @@ If you are running Java 21+ you can use [pattern matching for switch](https://op
```java
Vehicle vehicle = ...;
switch (vehicle.getCase()) {
case Vehicle.Bicycle b:
case Vehicle.Case.Bicycle b:
System.out.println("Bicycle maker: " + b.maker());
break;
case Vehicle.Car c:
case Vehicle.Case.Car c:
System.out.println("Car: " + c.arg0());
break;
}
Expand All @@ -258,7 +258,7 @@ or even, destructuring the records in the switch statement's pattern match direc
```java
Vehicle vehicle = ...;
switch (vehicle.getCase()) {
case Vehicle.Car(var name, var unused):
case Vehicle.Case.Car(var name, var unused):
System.out.println("Car: " + name);
break;
default:
Expand All @@ -270,21 +270,21 @@ For Java 16+ you can use [pattern matching for instanceof](https://openjdk.org/j
```java
Vehicle vehicle = ...;
Vehicle.Case case = vehicle.getCase();
if (case instanceof Vehicle.Bicycle b) {
if (case instanceof Vehicle.Case.Bicycle b) {
System.out.println("Bicycle maker: " + b.maker());
} else if(case instanceof Vehicle.Car c) {
} else if(case instanceof Vehicle.Case.Car c) {
System.out.println("Car: " + c.arg0());
}
```
For any previous Java versions you can resort to casting the `Case` to the expected type:
```java
Vehicle vehicle = ...;
Vehicle.Case case = vehicle.getCase();
if (case instanceof Vehicle.Bicycle) {
Vehicle.Bicycle b = (Vehicle.Bicycle) case;
if (case instanceof Vehicle.Case.Bicycle) {
Vehicle.Bicycle b = (Vehicle.Case.Bicycle) case;
System.out.println("Bicycle maker: " + b.maker());
} else if(case instanceof Vehicle.Car) {
Vehicle.Car c = (Vehicle.Car) case;
} else if(case instanceof Vehicle.Case.Car) {
Vehicle.Car c = (Vehicle.Case.Car) case;
System.out.println("Car: " + c.arg0());
}
```
Expand Down
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