prefix boolean variables with is to match Java conventions

Author: madsodgaard

Sources/JExtractSwiftLib/Convenience/String+Extensions.swift

@@ -22,4 +22,32 @@ extension String {
 
     return "\(f.uppercased())\(String(dropFirst()))"
   }
-}
+
+  /// Returns whether the string is of the format `isX`
+  private var hasJavaBooleanNamingConvention: Bool {
+    guard self.hasPrefix("is"), self.count > 2 else {
+      return false
+    }
+
+    let thirdCharacterIndex = self.index(self.startIndex, offsetBy: 2)
+    return self[thirdCharacterIndex].isUppercase
+  }
+
+  func javaGetterName(isBoolean: Bool) -> String {
+    if !isBoolean {
+      return "get\(self.toCamelCase)"
+    } else if !hasJavaBooleanNamingConvention {
+      return "is\(self.toCamelCase)"
+    } else {
+      return self.toCamelCase
+    }
+  }
+
+  func javaSetterName(isBoolean: Bool) -> String {
+    if !isBoolean || !hasJavaBooleanNamingConvention {
+      return "set\(self.toCamelCase)"
+    } else {
+      return "setIs\(self.toCamelCase)"
+    }
+  }
+}

Sources/JExtractSwiftLib/FFM/FFMSwift2JavaGenerator+JavaTranslation.swift

@@ -126,9 +126,10 @@ extension FFMSwift2JavaGenerator {
       let loweredSignature = try lowering.lowerFunctionSignature(decl.functionSignature)
 
       // Name.
+      let returnsBoolean = decl.functionSignature.result.type.asNominalTypeDeclaration?.knownTypeKind == .bool
       let javaName = switch decl.apiKind {
-      case .getter: "get\(decl.name.toCamelCase)"
-      case .setter: "set\(decl.name.toCamelCase)"
+      case .getter: decl.name.javaGetterName(isBoolean: returnsBoolean)
+      case .setter: decl.name.javaSetterName(isBoolean: returnsBoolean)
       case .function, .initializer: decl.name
       }
 

Sources/JExtractSwiftLib/ImportedDecls.swift

@@ -91,7 +91,7 @@ public final class ImportedFunc: ImportedDecl, CustomStringConvertible {
     }
     return false
   }
-  
+
   /// If this function/method is member of a class/struct/protocol,
   /// this will contain that declaration's imported name.
   ///

Sources/JExtractSwiftLib/JNI/JNISwift2JavaGenerator+JavaTranslation.swift

@@ -38,9 +38,10 @@ extension JNISwift2JavaGenerator {
       let parentName = decl.parentType?.asNominalType?.nominalTypeDecl.qualifiedName ?? swiftModuleName
 
       // Name.
+      let returnsBoolean = translatedFunctionSignature.resultType == .boolean
       let javaName = switch decl.apiKind {
-      case .getter: "get\(decl.name.toCamelCase)"
-      case .setter: "set\(decl.name.toCamelCase)"
+      case .getter: decl.name.javaGetterName(isBoolean: returnsBoolean)
+      case .setter: decl.name.javaSetterName(isBoolean: returnsBoolean)
       case .function, .initializer: decl.name
       }