[javac] Add readable test for sealed classes.

PiperOrigin-RevId: 777667014

Author: Googler

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/BUILD

@@ -0,0 +1,18 @@
+load(
+    "//transpiler/javatests/com/google/j2cl/readable:readable_example.bzl",
+    "readable_example",
+)
+
+package(
+    default_applicable_licenses = ["//:j2cl_license"],
+    licenses = ["notice"],
+)
+
+readable_example(
+    srcs = glob(["**/*.java"]),
+    experimental_java_frontend = "javac",
+    javacopts = [
+        "-source 21",
+        "-target 21",
+    ],
+)

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/SealedClasses.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2025 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sealedclasses;
+
+import sealedclasses.sealedclassinanotherpackage.SealedClassInAnotherPackage;
+
+public class SealedClasses {
+  public static final class SubClass extends SealedClassInAnotherPackage {}
+
+  public sealed interface Animal {}
+
+  public abstract static sealed class Mammal implements Animal {
+    public Mammal() {}
+
+    private Mammal(String name) {
+      this();
+    }
+
+    public String retrieveName() {
+      return "Animal";
+    }
+
+    public abstract void changeName(String updatedName);
+
+    // Subclasses can have any visibility
+    protected static final class Dolphin extends Mammal {
+      @Override
+      public void changeName(String updatedName) {}
+    }
+  }
+
+  public static final class Dog extends Mammal {
+    @Override
+    public void changeName(String updatedName) {}
+  }
+
+  static final class Cat extends Mammal {
+    @Override
+    public void changeName(String updatedName) {}
+  }
+
+  private static final class Whale extends Mammal {
+    @Override
+    public void changeName(String updatedName) {}
+  }
+
+  public static final class Deer implements Animal {
+    private Deer() {}
+  }
+
+  // Enum classes cannot extend a sealed class, but they can implement sealed interfaces.
+  enum EnumImplementsSealedInterface implements Animal {
+    V1,
+    V2
+  }
+
+  public abstract static sealed class Shape {
+    public static final class Circle extends Shape {}
+
+    public static final class Rectangle extends Shape {
+      private Rectangle() {}
+    }
+  }
+
+  // The else branch is not mandatory in when expression if when has a subject of sealed type
+  // TODO(b/286448526): Implement pattern matching switch.
+  // private static String checkShape(Shape e) {
+  //   return switch (e) {
+  //     case Shape.Circle c -> "Circle";
+  //     case Shape.Rectangle r -> "Rectangle";
+  //   };
+  // }
+
+  // Unlike Kotlin, sealed classes in Java can be concrete and subtypes can be inner classes.
+  public static sealed class SealedClassWithInnerClass {
+    public final class A extends SealedClassWithInnerClass {}
+
+    public final class B extends SealedClassWithInnerClass {}
+  }
+}

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/module-info.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright 2025 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+// Java allows subtypes of sealed classes to be defined in different packages, but they must be in
+// the same module and NOT the unnamed module.
+module sealedclasses {}

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Animal.impl.java.js.txt

@@ -0,0 +1,31 @@
+goog.module('sealedclasses.SealedClasses.Animal$impl');
+
+const $Util = goog.require('nativebootstrap.Util$impl');
+
+/**
+ * @interface
+ */
+class Animal {
+ /** @nodts */
+ static $clinit() {
+  Animal.$clinit = () =>{};
+  Animal.$loadModules();
+ }
+ 
+ static $markImplementor(/** Function */ ctor) {
+  ctor.prototype.$implements__sealedclasses_SealedClasses_Animal = true;
+ }
+ /** @nodts @return {boolean} */
+ static $isInstance(/** ? */ instance) {
+  return instance != null && !!instance.$implements__sealedclasses_SealedClasses_Animal;
+ }
+ 
+ /** @nodts */
+ static $loadModules() {}
+}
+Animal.$markImplementor(/**@type {Function}*/ (Animal));
+$Util.$setClassMetadataForInterface(/**@type {Function}*/ (Animal), 'sealedclasses.SealedClasses$Animal');
+
+exports = Animal;
+
+//# sourceMappingURL=SealedClasses$Animal.js.map

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Animal.java.js.txt

@@ -0,0 +1,6 @@
+goog.module('sealedclasses.SealedClasses.Animal');
+
+goog.require('nativebootstrap.Util');
+
+const Animal = goog.require('sealedclasses.SealedClasses.Animal$impl');
+exports = Animal;

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Cat.impl.java.js.txt

@@ -0,0 +1,45 @@
+goog.module('sealedclasses.SealedClasses.Cat$impl');
+
+const $Util = goog.require('nativebootstrap.Util$impl');
+const Mammal = goog.require('sealedclasses.SealedClasses.Mammal$impl');
+
+/**
+ * @final
+ */
+class Cat extends Mammal {
+ /** @protected @nodts */
+ constructor() {
+  super();
+ }
+ /** @nodts @return {!Cat} */
+ static $create__() {
+  Cat.$clinit();
+  let $instance = new Cat();
+  $instance.$ctor__sealedclasses_SealedClasses_Cat__void();
+  return $instance;
+ }
+ /** @nodts */
+ $ctor__sealedclasses_SealedClasses_Cat__void() {
+  this.$ctor__sealedclasses_SealedClasses_Mammal__void();
+ }
+ /** @override @nodts */
+ m_changeName__java_lang_String__void(/** ?string */ updatedName) {}
+ /** @nodts */
+ static $clinit() {
+  Cat.$clinit = () =>{};
+  Cat.$loadModules();
+  Mammal.$clinit();
+ }
+ /** @nodts @return {boolean} */
+ static $isInstance(/** ? */ instance) {
+  return instance instanceof Cat;
+ }
+ 
+ /** @nodts */
+ static $loadModules() {}
+}
+$Util.$setClassMetadata(Cat, 'sealedclasses.SealedClasses$Cat');
+
+exports = Cat;
+
+//# sourceMappingURL=SealedClasses$Cat.js.map

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Cat.java.js.txt

@@ -0,0 +1,7 @@
+goog.module('sealedclasses.SealedClasses.Cat');
+
+goog.require('nativebootstrap.Util');
+goog.require('sealedclasses.SealedClasses.Mammal');
+
+const Cat = goog.require('sealedclasses.SealedClasses.Cat$impl');
+exports = Cat;

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Deer.impl.java.js.txt

@@ -0,0 +1,45 @@
+goog.module('sealedclasses.SealedClasses.Deer$impl');
+
+const j_l_Object = goog.require('java.lang.Object$impl');
+const $Util = goog.require('nativebootstrap.Util$impl');
+const Animal = goog.require('sealedclasses.SealedClasses.Animal$impl');
+
+/**
+ * @final
+ * @implements {Animal}
+ */
+class Deer extends j_l_Object {
+ /** @protected @nodts */
+ constructor() {
+  super();
+ }
+ /** @nodts @return {!Deer} */
+ static $create__() {
+  let $instance = new Deer();
+  $instance.$ctor__sealedclasses_SealedClasses_Deer__void();
+  return $instance;
+ }
+ /** @nodts */
+ $ctor__sealedclasses_SealedClasses_Deer__void() {
+  this.$ctor__java_lang_Object__void();
+ }
+ /** @nodts */
+ static $clinit() {
+  Deer.$clinit = () =>{};
+  Deer.$loadModules();
+  j_l_Object.$clinit();
+ }
+ /** @nodts @return {boolean} */
+ static $isInstance(/** ? */ instance) {
+  return instance instanceof Deer;
+ }
+ 
+ /** @nodts */
+ static $loadModules() {}
+}
+Animal.$markImplementor(Deer);
+$Util.$setClassMetadata(Deer, 'sealedclasses.SealedClasses$Deer');
+
+exports = Deer;
+
+//# sourceMappingURL=SealedClasses$Deer.js.map

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Deer.java.js.txt

@@ -0,0 +1,8 @@
+goog.module('sealedclasses.SealedClasses.Deer');
+
+goog.require('java.lang.Object');
+goog.require('nativebootstrap.Util');
+goog.require('sealedclasses.SealedClasses.Animal');
+
+const Deer = goog.require('sealedclasses.SealedClasses.Deer$impl');
+exports = Deer;

transpiler/javatests/com/google/j2cl/readable/java/sealedclasses/output_closure/SealedClasses$Dog.impl.java.js.txt

@@ -0,0 +1,45 @@
+goog.module('sealedclasses.SealedClasses.Dog$impl');
+
+const $Util = goog.require('nativebootstrap.Util$impl');
+const Mammal = goog.require('sealedclasses.SealedClasses.Mammal$impl');
+
+/**
+ * @final
+ */
+class Dog extends Mammal {
+ /** @protected @nodts */
+ constructor() {
+  super();
+ }
+ /** @nodts @return {!Dog} */
+ static $create__() {
+  Dog.$clinit();
+  let $instance = new Dog();
+  $instance.$ctor__sealedclasses_SealedClasses_Dog__void();
+  return $instance;
+ }
+ /** @nodts */
+ $ctor__sealedclasses_SealedClasses_Dog__void() {
+  this.$ctor__sealedclasses_SealedClasses_Mammal__void();
+ }
+ /** @override @nodts */
+ m_changeName__java_lang_String__void(/** ?string */ updatedName) {}
+ /** @nodts */
+ static $clinit() {
+  Dog.$clinit = () =>{};
+  Dog.$loadModules();
+  Mammal.$clinit();
+ }
+ /** @nodts @return {boolean} */
+ static $isInstance(/** ? */ instance) {
+  return instance instanceof Dog;
+ }
+ 
+ /** @nodts */
+ static $loadModules() {}
+}
+$Util.$setClassMetadata(Dog, 'sealedclasses.SealedClasses$Dog');
+
+exports = Dog;
+
+//# sourceMappingURL=SealedClasses$Dog.js.map