JNI: Java enum constants keep the Swift case names

Samples/SwiftJavaExtractJNIKotlinSampleApp/src/test/kotlin/com/example/kotlin/JavaEnumsTest.kt

@@ -24,36 +24,36 @@ import kotlin.test.assertTrue
 class JavaEnumsTest {
     @Test
     fun exhaustiveWhen() {
-        val label = when (Orders.fill(OrderStatus.PENDING)) {
-            OrderStatus.PENDING -> "pending"
-            OrderStatus.FILLED -> "filled"
-            OrderStatus.CANCELLED -> "cancelled"
+        val label = when (Orders.fill(OrderStatus.pending)) {
+            OrderStatus.pending -> "pending"
+            OrderStatus.filled -> "filled"
+            OrderStatus.cancelled -> "cancelled"
         }
         assertEquals("filled", label)
     }
 
     @Test
     fun constantsAreTheValuesSwiftReturns() {
-        assertSame(OrderStatus.FILLED, Orders.fill(OrderStatus.PENDING))
+        assertSame(OrderStatus.filled, Orders.fill(OrderStatus.pending))
         assertEquals(OrderStatus.entries, Orders.all().toList())
-        assertEquals("cancelled", OrderStatus.CANCELLED.rawValue)
-        assertTrue(OrderStatus.CANCELLED.isFinal)
+        assertEquals("cancelled", OrderStatus.cancelled.rawValue)
+        assertTrue(OrderStatus.cancelled.isFinal)
     }
 
     @Test
     fun everywhereAValueCrosses() = runBlocking {
-        assertSame(OrderStatus.PENDING, Orders.status("a"))
-        assertSame(OrderStatus.FILLED, Orders.byID()["a"])
-        assertSame(OrderStatus.CANCELLED, Order.init("a", OrderStatus.CANCELLED).status)
-        assertSame(OrderStatus.FILLED, (Orders.event(OrderStatus.FILLED).case as OrderEvent.Case.Changed).arg0)
+        assertSame(OrderStatus.pending, Orders.status("a"))
+        assertSame(OrderStatus.filled, Orders.byID()["a"])
+        assertSame(OrderStatus.cancelled, Order.init("a", OrderStatus.cancelled).status)
+        assertSame(OrderStatus.filled, (Orders.event(OrderStatus.filled).case as OrderEvent.Case.Changed).arg0)
         var seen: OrderStatus? = null
         Orders.watch { seen = it }
-        assertSame(OrderStatus.CANCELLED, seen)
-        assertSame(OrderStatus.FILLED, Orders.settle().await())
+        assertSame(OrderStatus.cancelled, seen)
+        assertSame(OrderStatus.filled, Orders.settle().await())
     }
 
     @Test
     fun manyRoundTrips() {
-        repeat(10_000) { assertSame(OrderStatus.FILLED, Orders.fill(OrderStatus.FILLED)) }
+        repeat(10_000) { assertSame(OrderStatus.filled, Orders.fill(OrderStatus.filled)) }
     }
 }

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaBindingsPrinting.swift

@@ -313,7 +313,7 @@ extension JNISwift2JavaGenerator {
   private func printConcreteType(_ printer: inout JavaPrinter, _ decl: ExtractedNominalType) {
     printNominal(&printer, decl) { printer in
       if self.isJavaEnum(decl) {
-        printer.print(decl.cases.map { $0.name.uppercased() }.joined(separator: ", ") + ";")
+        printer.print(decl.cases.map { Self.javaEnumConstantName($0) }.joined(separator: ", ") + ";")
         printer.println()
       }
       printer.print(
@@ -679,6 +679,12 @@ extension JNISwift2JavaGenerator {
 
   /// Whether `decl` is printed as a Java `enum` (`payloadlessEnumsAsJavaEnums`): a non-generic,
   /// non-error Swift enum whose cases have no associated values.
+  /// The Swift case name, as Swift and Kotlin code spell the case; a Java keyword gets a trailing `_`.
+  static func javaEnumConstantName(_ enumCase: ExtractedEnumCase) -> String {
+    let name = enumCase.name.trimmingCharacters(in: CharacterSet(charactersIn: "`"))
+    return JavaIdentifierFactory.javaKeywords.contains(name) ? name + "_" : name
+  }
+
   func isJavaEnum(_ decl: ExtractedNominalType) -> Bool {
     config.effectivePayloadlessEnumsAsJavaEnums && decl.swiftNominal.kind == .enum && !decl.swiftNominal.isGeneric
       && !decl.cases.isEmpty && decl.cases.allSatisfy(\.parameters.isEmpty) && !self.isSwiftErrorType(decl)

Sources/SwiftJavaConfigurationShared/Configuration.swift

@@ -189,7 +189,7 @@ public struct Configuration: Codable {
   }
 
   /// If true, Swift enums whose cases have no associated values are generated as Java `enum`s,
-  /// with one constant per case, instead of classes wrapping a Swift value. Only supported in
+  /// with one constant per case named like the case, instead of classes wrapping a Swift value. Only supported in
   /// `jni` mode.
   public var payloadlessEnumsAsJavaEnums: Bool?
   public var effectivePayloadlessEnumsAsJavaEnums: Bool {

Sources/SwiftJavaDocumentation/Documentation.docc/SwiftJavaConfigFile.md

@@ -262,7 +262,7 @@ extract or translate, and lists each one. Skipped declarations are always report
 - **Default:** `false`
 
 If true, Swift enums whose cases have no associated values are generated as Java `enum`s,
-with one constant per case, instead of classes wrapping a Swift value. Only supported in
+with one constant per case named like the case, instead of classes wrapping a Swift value. Only supported in
 `jni` mode.
 
 ---

Tests/JExtractSwiftTests/JNI/JNIJavaEnumTests.swift

@@ -32,6 +32,23 @@ struct JNIJavaEnumTests {
     }
     """
 
+  @Test
+  func javaKeywordCaseIsEscaped() throws {
+    try assertOutput(
+      input: """
+        public enum Policy {
+          case `default`
+          case strict
+        }
+        """,
+      config: config,
+      .jni,
+      .java,
+      detectChunkByInitialLines: 1,
+      expectedChunks: ["default_, strict;"]
+    )
+  }
+
   @Test
   func casesBecomeConstants() throws {
     try assertOutput(
@@ -42,7 +59,8 @@ struct JNIJavaEnumTests {
       detectChunkByInitialLines: 1,
       expectedChunks: [
         "public enum Phase implements JNISwiftInstance {",
-        "IDLE, LOADING;",
+        // Swift case names, as Swift and Kotlin code spell them.
+        "idle, loading;",
         "static final long[] ADDRESSES = { Phase.$idle(), Phase.$loading() };",
         """
         public static Phase wrapMemoryAddressUnsafe(long selfPointer) {