J2K converter: automatic generation of 'open' modifier for classes and methods

j2k/src/org/jetbrains/jet/j2k/ClassBodyConverter.kt

@@ -47,7 +47,8 @@ enum class AccessorKind {
 }
 
 class ClassBodyConverter(private val psiClass: PsiClass,
-                         private val converter: Converter) {
+                         private val converter: Converter,
+                         private val isOpenClass: Boolean) {
     private val membersToRemove = HashSet<PsiMember>()
     private val fieldCorrections = HashMap<PsiField, FieldCorrectionInfo>()
 
@@ -110,7 +111,7 @@ class ClassBodyConverter(private val psiClass: PsiClass,
                                         membersToRemove: MutableSet<PsiMember>,
                                         constructorConverter: ConstructorConverter?): Member? {
         return when (member) {
-            is PsiMethod -> convertMethod(member, membersToRemove, constructorConverter)
+            is PsiMethod -> convertMethod(member, membersToRemove, constructorConverter, isOpenClass)
             is PsiField -> convertField(member, fieldCorrections[member])
             is PsiClass -> convertClass(member)
             is PsiClassInitializer -> convertInitializer(member)

j2k/src/org/jetbrains/jet/j2k/CodeConverter.kt

@@ -148,7 +148,7 @@ class CodeConverter(public val converter: Converter,
     }
 
     public fun convertAnonymousClassBody(anonymousClass: PsiAnonymousClass): AnonymousClassBody {
-        return AnonymousClassBody(ClassBodyConverter(anonymousClass, converter).convertBody(),
+        return AnonymousClassBody(ClassBodyConverter(anonymousClass, converter, false).convertBody(),
                                   anonymousClass.getBaseClassType().resolve()?.isInterface() ?: false).assignPrototype(anonymousClass)
     }
 

j2k/src/org/jetbrains/jet/j2k/Converter.kt

@@ -95,7 +95,7 @@ class Converter private(private val elementToConvert: PsiElement,
     private fun convertTopElement(element: PsiElement): Element? = when (element) {
         is PsiJavaFile -> convertFile(element)
         is PsiClass -> convertClass(element)
-        is PsiMethod -> convertMethod(element, null, null)
+        is PsiMethod -> convertMethod(element, null, null, false)
         is PsiField -> convertField(element, null)
         is PsiStatement -> createDefaultCodeConverter().convertStatement(element)
         is PsiExpression -> createDefaultCodeConverter().convertExpression(element)
@@ -179,15 +179,19 @@ class Converter private(private val elementToConvert: PsiElement,
         val extendsTypes = convertToNotNullableTypes(psiClass.getExtendsListTypes())
         val name = psiClass.declarationIdentifier()
 
-        var classBody = ClassBodyConverter(psiClass, this).convertBody()
-
         return when {
-            psiClass.isInterface() -> Trait(name, annotations, modifiers, typeParameters, extendsTypes, listOf(), implementsTypes, classBody)
+            psiClass.isInterface() -> {
+                var classBody = ClassBodyConverter(psiClass, this, false).convertBody()
+                Trait(name, annotations, modifiers, typeParameters, extendsTypes, listOf(), implementsTypes, classBody)
+            }
 
-            psiClass.isEnum() -> Enum(name, annotations, modifiers, typeParameters, listOf(), listOf(), implementsTypes, classBody)
+            psiClass.isEnum() -> {
+                var classBody = ClassBodyConverter(psiClass, this, false).convertBody()
+                Enum(name, annotations, modifiers, typeParameters, listOf(), listOf(), implementsTypes, classBody)
+            }
 
             else -> {
-                if (settings.openByDefault && !psiClass.hasModifierProperty(PsiModifier.FINAL)) {
+                if (needOpenModifier(psiClass)) {
                     modifiers = modifiers.with(Modifier.OPEN)
                 }
 
@@ -195,11 +199,20 @@ class Converter private(private val elementToConvert: PsiElement,
                     modifiers = modifiers.with(Modifier.INNER)
                 }
 
+                var classBody = ClassBodyConverter(psiClass, this, modifiers.contains(Modifier.OPEN)).convertBody()
+
                 Class(name, annotations, modifiers, typeParameters, extendsTypes, classBody.baseClassParams, implementsTypes, classBody)
             }
         }.assignPrototype(psiClass)
     }
 
+    private fun needOpenModifier(psiClass: PsiClass): Boolean {
+        return if (settings.openByDefault)
+            !psiClass.hasModifierProperty(PsiModifier.FINAL) && !psiClass.hasModifierProperty(PsiModifier.ABSTRACT)
+        else
+            referenceSearcher.hasInheritors(psiClass)
+    }
+
     private fun convertAnnotationType(psiClass: PsiClass): Class {
         val paramModifiers = Modifiers(listOf(Modifier.PUBLIC)).assignNoPrototype()
         val noBlankLinesInheritance = CommentsAndSpacesInheritance(blankLinesBefore = false)
@@ -224,7 +237,7 @@ class Converter private(private val elementToConvert: PsiElement,
         val constructorSignature = PrimaryConstructorSignature(Annotations.Empty(), Modifiers.Empty(), parameterList).assignNoPrototype()
 
         // to convert fields and nested types - they are not allowed in Kotlin but we convert them and let user refactor code
-        var classBody = ClassBodyConverter(psiClass, this).convertBody()
+        var classBody = ClassBodyConverter(psiClass, this, false).convertBody()
         classBody = ClassBody(constructorSignature, classBody.baseClassParams, classBody.members, classBody.classObjectMembers, listOf(), classBody.lBrace, classBody.rBrace)
 
         val annotationAnnotation = Annotation(Identifier("annotation").assignNoPrototype(), listOf(), false, false).assignNoPrototype()
@@ -299,11 +312,18 @@ class Converter private(private val elementToConvert: PsiElement,
         return if (convertedType == initializerType) null else convertedType
     }
 
-    public fun convertMethod(method: PsiMethod, membersToRemove: MutableSet<PsiMember>?, constructorConverter: ConstructorConverter?): Member? {
+    public fun convertMethod(method: PsiMethod,
+                             membersToRemove: MutableSet<PsiMember>?,
+                             constructorConverter: ConstructorConverter?,
+                             isInOpenClass: Boolean): Member? {
         val returnType = typeConverter.convertMethodReturnType(method)
 
         val annotations = (convertAnnotations(method) + convertThrows(method)).assignNoPrototype()
+
         var modifiers = convertModifiers(method)
+        if (needOpenModifier(method, isInOpenClass, modifiers)) {
+            modifiers = modifiers.with(Modifier.OPEN)
+        }
 
         val statementsToInsert = ArrayList<Statement>()
         for (parameter in method.getParameterList().getParameters()) {
@@ -392,6 +412,19 @@ class Converter private(private val elementToConvert: PsiElement,
         return false
     }
 
+    private fun needOpenModifier(method: PsiMethod, isInOpenClass: Boolean, modifiers: Modifiers): Boolean {
+        if (!isInOpenClass) return false
+        if (modifiers.contains(Modifier.OVERRIDE) || modifiers.contains(Modifier.ABSTRACT)) return false
+        if (settings.openByDefault) {
+           return !method.hasModifierProperty(PsiModifier.FINAL)
+                  && !method.hasModifierProperty(PsiModifier.PRIVATE)
+                  && !method.hasModifierProperty(PsiModifier.STATIC)
+        }
+        else {
+            return referenceSearcher.hasOverrides(method)
+        }
+    }
+
     public fun convertCodeReferenceElement(element: PsiJavaCodeReferenceElement, hasExternalQualifier: Boolean, typeArgsConverted: List<Element>? = null): ReferenceElement {
         val typeArgs = typeArgsConverted ?: typeConverter.convertTypes(element.getTypeParameters())
 

j2k/src/org/jetbrains/jet/j2k/ReferenceSearcher.kt

@@ -23,16 +23,22 @@ import com.intellij.psi.search.searches.ReferencesSearch
 import com.intellij.psi.search.LocalSearchScope
 import com.intellij.psi.PsiMethod
 import com.intellij.psi.PsiMethodCallExpression
-import java.util.Collections
+import com.intellij.psi.PsiClass
+import com.intellij.psi.search.searches.ClassInheritorsSearch
+import com.intellij.psi.search.searches.OverridingMethodsSearch
 
 public trait ReferenceSearcher {
     fun findVariableUsages(variable: PsiVariable, scope: PsiElement): Collection<PsiReferenceExpression>
     fun findMethodCalls(method: PsiMethod, scope: PsiElement): Collection<PsiMethodCallExpression>
+    fun hasInheritors(`class`: PsiClass): Boolean
+    fun hasOverrides(method: PsiMethod): Boolean
 }
 
 public object EmptyReferenceSearcher: ReferenceSearcher {
     override fun findVariableUsages(variable: PsiVariable, scope: PsiElement) = listOf<PsiReferenceExpression>()
     override fun findMethodCalls(method: PsiMethod, scope: PsiElement) = listOf<PsiMethodCallExpression>()
+    override fun hasInheritors(`class`: PsiClass) = false
+    override fun hasOverrides(method: PsiMethod) = false
 }
 
 public object IdeaReferenceSearcher : ReferenceSearcher {
@@ -51,4 +57,8 @@ public object IdeaReferenceSearcher : ReferenceSearcher {
             }
         }.filterNotNull()
     }
+
+    override fun hasInheritors(`class`: PsiClass) = ClassInheritorsSearch.search(`class`, false).any()
+
+    override fun hasOverrides(method: PsiMethod) = OverridingMethodsSearch.search(method, false).any()
 }

j2k/tests/test/org/jetbrains/jet/j2k/test/JavaToKotlinConverterForWebDemoTestGenerated.java

@@ -2162,6 +2162,12 @@ public class JavaToKotlinConverterForWebDemoTestGenerated extends AbstractJavaTo
             String fileName = JetTestUtils.navigationMetadata("j2k/tests/testData/fileOrElement/inheritance/classOneExtendsBaseWithZeroParamsNonEmptyConstructor.java");
             doTest(fileName);
         }
+
+        @TestMetadata("openModifier.java")
+        public void testOpenModifier() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/tests/testData/fileOrElement/inheritance/openModifier.java");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("j2k/tests/testData/fileOrElement/isOperator")

j2k/tests/test/org/jetbrains/jet/j2k/test/JavaToKotlinConverterSingleFileTestGenerated.java

@@ -2162,6 +2162,12 @@ public class JavaToKotlinConverterSingleFileTestGenerated extends AbstractJavaTo
             String fileName = JetTestUtils.navigationMetadata("j2k/tests/testData/fileOrElement/inheritance/classOneExtendsBaseWithZeroParamsNonEmptyConstructor.java");
             doTest(fileName);
         }
+
+        @TestMetadata("openModifier.java")
+        public void testOpenModifier() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/tests/testData/fileOrElement/inheritance/openModifier.java");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("j2k/tests/testData/fileOrElement/isOperator")

j2k/tests/testData/fileOrElement/constructors/fieldsInitializedFromParams8.kt

@@ -1,4 +1,3 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base(o: Any, l: Int)
-class Base(o: Any, l: Int)
 
 class C(private val string: String) : Base(string, string.length())

j2k/tests/testData/fileOrElement/constructors/nestedClassNameInSuperParameters.kt

@@ -1,5 +1,4 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base(nested: Base.Nested) {
-class Base(nested: Base.Nested) {
 
     class Nested(p: Int) {
         class object {

j2k/tests/testData/fileOrElement/dropAccessors/DifferentFieldNameAndSuperClass.kt

@@ -1,5 +1,4 @@
-// ERROR: This type is final, so it cannot be inherited from
+public open class Base(x: Int) {
-public class Base(x: Int) {
     public var x: Int = 42
         protected set
 

j2k/tests/testData/fileOrElement/dropAccessors/DifferentProtectedFieldName.kt

@@ -1,5 +1,4 @@
-// ERROR: This type is final, so it cannot be inherited from
+public open class AAA {
-public class AAA {
     public var x: Int = 42
         protected set
 

j2k/tests/testData/fileOrElement/field/classChildExtendsBase.kt

@@ -1,5 +1,4 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base {
-class Base {
     private val myFirst: String? = null
 }
 

j2k/tests/testData/fileOrElement/function/extendsBaseWhichExtendsObject.kt

@@ -1,6 +1,3 @@
-// ERROR: 'clone' in 'Base' is final and cannot be overridden
-// ERROR: 'finalize' in 'Base' is final and cannot be overridden
-// ERROR: This type is final, so it cannot be inherited from
 // ERROR: Unresolved reference: clone
 // ERROR: Unresolved reference: finalize
 package test
@@ -29,7 +26,7 @@ class Test : Base() {
     }
 }
 
-class Base {
+open class Base {
     override fun hashCode(): Int {
         return super.hashCode()
     }
@@ -39,7 +36,7 @@ class Base {
     }
 
     throws(javaClass<CloneNotSupportedException>())
-    protected fun clone(): Any {
+    protected open fun clone(): Any {
         return super.clone()
     }
 
@@ -48,7 +45,7 @@ class Base {
     }
 
     throws(javaClass<Throwable>())
-    protected fun finalize() {
+    protected open fun finalize() {
         super.finalize()
     }
 }

j2k/tests/testData/fileOrElement/function/override.kt

@@ -1,7 +1,5 @@
-// ERROR: 'a' in 'A' is final and cannot be overridden
+open class A {
-// ERROR: This type is final, so it cannot be inherited from
+    open fun a() {
-class A {
-    fun a() {
     }
 }
 

j2k/tests/testData/fileOrElement/function/overrideAndOpen.kt

@@ -1,12 +1,9 @@
-// ERROR: 'foo' in 'A' is final and cannot be overridden
+open class A {
-// ERROR: This type is final, so it cannot be inherited from
+    open fun foo() {
-// ERROR: This type is final, so it cannot be inherited from
-class A {
-    fun foo() {
     }
 }
 
-class B : A() {
+open class B : A() {
     override fun foo() {
     }
 }

j2k/tests/testData/fileOrElement/function/overrideObject2.kt

@@ -1,6 +1,5 @@
-// ERROR: This type is final, so it cannot be inherited from
 // ERROR: Unresolved reference: clone
-class Base
+open class Base
 
 class X : Base() {
     override fun hashCode(): Int {

j2k/tests/testData/fileOrElement/function/overrideObject3.kt

@@ -1,5 +1,4 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base {
-class Base {
     override fun equals(o: Any?): Boolean {
         return super.equals(o)
     }

j2k/tests/testData/fileOrElement/identifier/finalFieldReference.kt

@@ -1,7 +1,6 @@
-// ERROR: This type is final, so it cannot be inherited from
 class `$$$$$`
 
-class `$`
+open class `$`
 
 class `$$`(val `$$$`: `$$$$$`) : `$`() {
 

j2k/tests/testData/fileOrElement/inheritance/classOneExtendsBaseGeneric.kt

@@ -1,4 +1,3 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base<T>(name: T)
-class Base<T>(name: T)
 
 class One<T, K>(name: T, private val mySecond: K) : Base<T>(name)

j2k/tests/testData/fileOrElement/inheritance/classOneExtendsBaseWithOneParam.kt

@@ -1,4 +1,3 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base(name: String)
-class Base(name: String)
 
 class One(name: String, second: String) : Base(name)

j2k/tests/testData/fileOrElement/inheritance/classOneExtendsBaseWithZeroParams.kt

@@ -1,4 +1,3 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base
-class Base
 
 class One : Base()

j2k/tests/testData/fileOrElement/inheritance/classOneExtendsBaseWithZeroParamsNonEmptyConstructor.kt

@@ -1,4 +1,3 @@
-// ERROR: This type is final, so it cannot be inherited from
+open class Base(name: String)
-class Base(name: String)
 
 class One(name: String, private val mySecond: String) : Base(name)

j2k/tests/testData/fileOrElement/inheritance/openModifier.java

@@ -0,0 +1,48 @@
+import java.lang.Override;
+import java.lang.Void;
+
+class A {
+    public void f1(){}
+    public void f2(){}
+    private void f3(){}
+}
+
+class B extends A {
+    @Override
+    public void f1() {
+        super.f1();
+    }
+}
+
+class C extends B {
+    @Override
+    public void f1() {
+        super.f1();
+    }
+}
+
+interface I {
+    void f();
+}
+
+class D implements I {
+    @Override
+    public void f() { }
+}
+
+abstract class E {
+    abstract void f1();
+    void f2(){}
+    void f3(){}
+}
+
+class F extends E {
+    @Override
+    void f1() {
+    }
+
+    @Override
+    void f2() {
+        super.f2();
+    }
+}

j2k/tests/testData/fileOrElement/inheritance/openModifier.kt

@@ -0,0 +1,51 @@
+import java.lang.Void
+
+open class A {
+    public open fun f1() {
+    }
+
+    public fun f2() {
+    }
+
+    private fun f3() {
+    }
+}
+
+open class B : A() {
+    override fun f1() {
+        super.f1()
+    }
+}
+
+class C : B() {
+    override fun f1() {
+        super.f1()
+    }
+}
+
+trait I {
+    public fun f()
+}
+
+class D : I {
+    override fun f() {
+    }
+}
+
+abstract class E {
+    abstract fun f1()
+    open fun f2() {
+    }
+
+    fun f3() {
+    }
+}
+
+class F : E() {
+    override fun f1() {
+    }
+
+    override fun f2() {
+        super.f2()
+    }
+}

j2k/tests/testData/fileOrElement/issues/kt-5400.kt

@@ -1,6 +1,5 @@
-// ERROR: This type is final, so it cannot be inherited from
 // ERROR: Property must be initialized or be abstract
-class Base {
+open class Base {
     inner class Nested
 }
 

j2k/tests/testData/fileOrElement/issues/kt-696.kt

@@ -1,7 +1,6 @@
-// ERROR: This type is final, so it cannot be inherited from
 package test
 
-class Base {
+open class Base {
     override fun hashCode(): Int {
         return super.hashCode()
     }

j2k/tests/testData/fileOrElement/issues/kt-836.kt

@@ -1,5 +1,3 @@
-// ERROR: 'test' in 'Base' is final and cannot be overridden
-// ERROR: This type is final, so it cannot be inherited from
 package com.voltvoodoo.saplo4j.model
 
 import java.io.Serializable
@@ -12,8 +10,8 @@ public class Language(protected var code: String) : Serializable {
 }
 
 
-class Base {
+open class Base {
-    fun test() {
+    open fun test() {
     }
 
     override fun toString(): String {

j2k/tests/testData/fileOrElement/nullability/OverrideWithInheritanceLoop.kt

@@ -1,13 +1,11 @@
 // ERROR: There's a cycle in the inheritance hierarchy for this type
 // ERROR: There's a cycle in the inheritance hierarchy for this type
-// ERROR: This type is final, so it cannot be inherited from
+open class A : B() {
-// ERROR: This type is final, so it cannot be inherited from
+    public open fun foo(s: String) {
-class A : B() {
-    public fun foo(s: String) {
     }
 }
 
-class B : A() {
+open class B : A() {
-    public fun foo(s: String) {
+    public open fun foo(s: String) {
     }
 }

j2k/tests/testData/fileOrElement/nullability/Overrides.kt

@@ -1,16 +1,13 @@
-// ERROR: 'foo' in 'Base' is final and cannot be overridden
+open class Base {
-// ERROR: 'bar' in 'Base' is final and cannot be overridden
+    public open fun foo(s: String?): String? {
-// ERROR: This type is final, so it cannot be inherited from
-class Base {
-    public fun foo(s: String?): String? {
         return ""
     }
 
-    public fun bar(s: String?): String? {
+    public open fun bar(s: String?): String? {
         return if (s != null) s + 1 else null
     }
 
-    public fun zoo(o: Any): String {
+    public open fun zoo(o: Any): String {
         return ""
     }
 }

j2k/tests/testData/fileOrElement/objectLiteral/MyFrame.kt

@@ -1,18 +1,15 @@
-// ERROR: This type is final, so it cannot be inherited from
-// ERROR: This type is final, so it cannot be inherited from
-// ERROR: This type is final, so it cannot be inherited from
 package demo
 
 trait WindowListener {
     public fun windowClosing()
 }
 
-class WindowAdapter : WindowListener {
+open class WindowAdapter : WindowListener {
     override fun windowClosing() {
     }
 }
 
-class Frame {
+open class Frame {
     public fun addWindowListener(listener: WindowListener) {
     }
 }

j2k/tests/testData/fileOrElement/settings/openByDefault.kt

@@ -1,7 +1,7 @@
 // !openByDefault: true
 
 open class A {
-    open fun foo1() {
+    open open fun foo1() {
     }
 
     private fun foo2() {

j2k/tests/testData/fileOrElement/superExpression/classAdotSuperFoo.kt

@@ -1,7 +1,6 @@
-// ERROR: This type is final, so it cannot be inherited from
 package a.b
 
-class Base {
+open class Base {
     fun foo() {
     }
 }

j2k/tests/testData/fileOrElement/superExpression/classAextendsB.java

@@ -1,4 +1,3 @@
-//class
 class B {
   B(int i) {}
   int call() {return 1;}

j2k/tests/testData/fileOrElement/superExpression/classAextendsB.kt

@@ -1,5 +1,5 @@
-class B(i: Int) {
+open class B(i: Int) {
-    fun call(): Int {
+    open fun call(): Int {
         return 1
     }
 }

j2k/tests/testData/fileOrElement/thisExpression/classAdotThisFoo.kt

@@ -1,7 +1,6 @@
-// ERROR: This type is final, so it cannot be inherited from
 package a.b
 
-class Base {
+open class Base {
     fun foo() {
     }
 }