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Merged
ktoso merged 9 commits into from
Mar 26, 2026
Merged

jextract-jni: Add type parameters to generated java types #648

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6438c71
Add generic parameter to generated java class
sidepelican Mar 25, 2026
22c3987
Add test for functions taking concrete generic type argument
sidepelican Mar 25, 2026
211160f
Add roundtrip test code
sidepelican Mar 25, 2026
01424fa
Considering generic argument value
sidepelican Mar 25, 2026
552c1b6
Add translateGenericTypeParameter
sidepelican Mar 25, 2026
013c5e6
Add Date and Date support
sidepelican Mar 26, 2026
afc146a
Update document
sidepelican Mar 26, 2026
1159b63
format
sidepelican Mar 26, 2026
7d16e29
Add explicit type
sidepelican Mar 26, 2026
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8 changes: 8 additions & 0 deletions Samples/SwiftJavaExtractJNISampleApp/Sources/MySwiftLibrary/GenericType.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,14 @@ public func makeStringID(_ value: String) -> MyID<String> {
MyID(value)
}

public func takeIntValue(from value: MyID<Int>) -> Int {
value.rawValue
}

public func takeStringValue(from value: MyID<String>) -> String {
value.rawValue
}

public struct MyEntity {
public var id: MyID<Int>
public var name: String
Expand Down
12 changes: 7 additions & 5 deletions Samples/SwiftJavaExtractJNISampleApp/src/test/java/com/example/swift/GenericTypeTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,20 +21,22 @@

public class GenericTypeTest {
@Test
void returnsGenericType() {
void genericTypeValueRoundtrip() {
try (var arena = SwiftArena.ofConfined()) {
MyID stringId = MySwiftLibrary.makeStringID("Java", arena);
MyID<String> stringId = MySwiftLibrary.makeStringID("Java", arena);
assertEquals("Java", stringId.getDescription());
assertEquals("Java", MySwiftLibrary.takeStringValue(stringId));

MyID intId = MySwiftLibrary.makeIntID(42, arena);
MyID<Long> intId = MySwiftLibrary.makeIntID(42, arena);
assertEquals("42", intId.getDescription());
assertEquals(42, MySwiftLibrary.takeIntValue(intId));
}
}

@Test
void genericTypeProperty() {
try (var arena = SwiftArena.ofConfined()) {
MyID intId = MySwiftLibrary.makeIntID(42, arena);
MyID<Long> intId = MySwiftLibrary.makeIntID(42, arena);
MyEntity entity = MyEntity.init(intId, "name", arena);
assertEquals("42", entity.getId(arena).getDescription());
}
Expand All @@ -43,7 +45,7 @@ void genericTypeProperty() {
@Test
void genericEnum() {
try (var arena = SwiftArena.ofConfined()) {
GenericEnum value = MySwiftLibrary.makeIntGenericEnum(arena);
GenericEnum<Long> value = MySwiftLibrary.makeIntGenericEnum(arena);
switch (value.getCase()) {
case GenericEnum.Foo _ -> assertTrue(value.getAsFoo().isPresent());
case GenericEnum.Bar _ -> assertTrue(value.getAsBar().isPresent());
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22 changes: 17 additions & 5 deletions Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaBindingsPrinting.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -234,6 +234,12 @@ extension JNISwift2JavaGenerator {
)
}
printer.println()
let genericClause =
if decl.swiftNominal.isGeneric {
"<\(decl.swiftNominal.genericParameters.map(\.name).joined(separator: ", "))>"
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@ktoso ktoso Mar 26, 2026

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👍

} else {
""
}
printer.print(
"""
/**
Expand All @@ -245,12 +251,12 @@ extension JNISwift2JavaGenerator {
* <li>This operation does not copy, or retain, the pointed at pointer, so its lifetime must be ensured manually to be valid when wrapping.</li>
* </ul>
*/
public static \(decl.swiftNominal.name) wrapMemoryAddressUnsafe(\(swiftPointerArg), SwiftArena swiftArena) {
return new \(decl.swiftNominal.name)(\(swiftPointerParams.joined(separator: ", ")), swiftArena);
public static\(genericClause) \(decl.swiftNominal.name)\(genericClause) wrapMemoryAddressUnsafe(\(swiftPointerArg), SwiftArena swiftArena) {
return new \(decl.swiftNominal.name)\(genericClause)(\(swiftPointerParams.joined(separator: ", ")), swiftArena);
}

public static \(decl.swiftNominal.name) wrapMemoryAddressUnsafe(\(swiftPointerArg)) {
return new \(decl.swiftNominal.name)(\(swiftPointerParams.joined(separator: ", ")), SwiftMemoryManagement.DEFAULT_SWIFT_JAVA_AUTO_ARENA);
public static\(genericClause) \(decl.swiftNominal.name)\(genericClause) wrapMemoryAddressUnsafe(\(swiftPointerArg)) {
return new \(decl.swiftNominal.name)\(genericClause)(\(swiftPointerParams.joined(separator: ", ")), SwiftMemoryManagement.DEFAULT_SWIFT_JAVA_AUTO_ARENA);
}
"""
)
Expand Down Expand Up @@ -384,8 +390,14 @@ extension JNISwift2JavaGenerator {
.filter { $0.kind == .protocol }
.map(\.name)
let implementsClause = implements.joined(separator: ", ")
let genericClause =
if decl.swiftNominal.isGeneric {
"<\(decl.swiftNominal.genericParameters.map(\.name).joined(separator: ", "))>"
} else {
""
}
printer.printBraceBlock(
"\(modifiers.joined(separator: " ")) class \(decl.swiftNominal.name) implements \(implementsClause)"
"\(modifiers.joined(separator: " ")) class \(decl.swiftNominal.name)\(genericClause) implements \(implementsClause)"
) { printer in
body(&printer)
}
Expand Down
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