Support sealed classes

This implements support for JEP 409: Sealed Classes, see
https://openjdk.java.net/jeps/409.

The implementation handles the sealed and non-sealed keywords and sorts them
according to their JLS order.  This requires us to look at the actual text of
the Tok, as there’s no TokenKind for sealed and non-sealed.

The optional permits clause is handled in the same manner as the implements
clause. A new private method, classDeclarationTypeList, has been added to
facilitate this.

This fixes #603.

I implemented this in a manner that I deemed fit with the surrounding code, but if I missed something, don’t hesitate to get back to me and I’ll adjust this PR to suit.

Fixes #629

COPYBARA_INTEGRATE_REVIEW=#629 from now:I603 4825e33
PiperOrigin-RevId: 387160750

Author: now

core/src/main/java/com/google/googlejavaformat/java/JavaInputAstVisitor.java

@@ -1961,8 +1961,10 @@ public void visitClassDeclaration(ClassTree node) {
             node.getModifiers(),
             Direction.VERTICAL,
             /* declarationAnnotationBreak= */ Optional.empty());
+    List<? extends Tree> permitsTypes = getPermitsClause(node);
     boolean hasSuperclassType = node.getExtendsClause() != null;
     boolean hasSuperInterfaceTypes = !node.getImplementsClause().isEmpty();
+    boolean hasPermitsTypes = !permitsTypes.isEmpty();
     builder.addAll(breaks);
     token(node.getKind() == Tree.Kind.INTERFACE ? "interface" : "class");
     builder.space();
@@ -1975,30 +1977,18 @@ public void visitClassDeclaration(ClassTree node) {
       if (!node.getTypeParameters().isEmpty()) {
         typeParametersRest(
             node.getTypeParameters(),
-            hasSuperclassType || hasSuperInterfaceTypes ? plusFour : ZERO);
+            hasSuperclassType || hasSuperInterfaceTypes || hasPermitsTypes ? plusFour : ZERO);
       }
       if (hasSuperclassType) {
         builder.breakToFill(" ");
         token("extends");
         builder.space();
         scan(node.getExtendsClause(), null);
       }
-      if (hasSuperInterfaceTypes) {
-        builder.breakToFill(" ");
-        builder.open(node.getImplementsClause().size() > 1 ? plusFour : ZERO);
-        token(node.getKind() == Tree.Kind.INTERFACE ? "extends" : "implements");
-        builder.space();
-        boolean first = true;
-        for (Tree superInterfaceType : node.getImplementsClause()) {
-          if (!first) {
-            token(",");
-            builder.breakOp(" ");
-          }
-          scan(superInterfaceType, null);
-          first = false;
-        }
-        builder.close();
-      }
+      classDeclarationTypeList(
+          node.getKind() == Tree.Kind.INTERFACE ? "extends" : "implements",
+          node.getImplementsClause());
+      classDeclarationTypeList("permits", permitsTypes);
     }
     builder.close();
     if (node.getMembers() == null) {
@@ -2277,6 +2267,8 @@ boolean nextIsModifier() {
       case "native":
       case "strictfp":
       case "default":
+      case "sealed":
+      case "non-sealed":
         return true;
       default:
         return false;
@@ -3549,6 +3541,31 @@ protected void addBodyDeclarations(
     }
   }
 
+  /** Gets the permits clause for the given node. This is only available in Java 15 and later. */
+  protected List<? extends Tree> getPermitsClause(ClassTree node) {
+    return ImmutableList.of();
+  }
+
+  private void classDeclarationTypeList(String token, List<? extends Tree> types) {
+    if (types.isEmpty()) {
+      return;
+    }
+    builder.breakToFill(" ");
+    builder.open(types.size() > 1 ? plusFour : ZERO);
+    token(token);
+    builder.space();
+    boolean first = true;
+    for (Tree type : types) {
+      if (!first) {
+        token(",");
+        builder.breakOp(" ");
+      }
+      scan(type, null);
+      first = false;
+    }
+    builder.close();
+  }
+
   /**
    * The parser expands multi-variable declarations into separate single-variable declarations. All
    * of the fragments in the original declaration have the same start position, so we use that as a

core/src/main/java/com/google/googlejavaformat/java/ModifierOrderer.java

@@ -36,44 +36,6 @@
 /** Fixes sequences of modifiers to be in JLS order. */
 final class ModifierOrderer {
 
-  /**
-   * Returns the {@link javax.lang.model.element.Modifier} for the given token kind, or {@code
-   * null}.
-   */
-  private static Modifier getModifier(TokenKind kind) {
-    if (kind == null) {
-      return null;
-    }
-    switch (kind) {
-      case PUBLIC:
-        return Modifier.PUBLIC;
-      case PROTECTED:
-        return Modifier.PROTECTED;
-      case PRIVATE:
-        return Modifier.PRIVATE;
-      case ABSTRACT:
-        return Modifier.ABSTRACT;
-      case STATIC:
-        return Modifier.STATIC;
-      case DEFAULT:
-        return Modifier.DEFAULT;
-      case FINAL:
-        return Modifier.FINAL;
-      case TRANSIENT:
-        return Modifier.TRANSIENT;
-      case VOLATILE:
-        return Modifier.VOLATILE;
-      case SYNCHRONIZED:
-        return Modifier.SYNCHRONIZED;
-      case NATIVE:
-        return Modifier.NATIVE;
-      case STRICTFP:
-        return Modifier.STRICTFP;
-      default:
-        return null;
-    }
-  }
-
   /** Reorders all modifiers in the given text to be in JLS order. */
   static JavaInput reorderModifiers(String text) throws FormatterException {
     return reorderModifiers(
@@ -152,7 +114,44 @@ private static void addTrivia(StringBuilder replacement, ImmutableList<? extends
    * is not a modifier.
    */
   private static Modifier asModifier(Token token) {
-    return getModifier(((JavaInput.Tok) token.getTok()).kind());
+    TokenKind kind = ((JavaInput.Tok) token.getTok()).kind();
+    if (kind != null) {
+      switch (kind) {
+        case PUBLIC:
+          return Modifier.PUBLIC;
+        case PROTECTED:
+          return Modifier.PROTECTED;
+        case PRIVATE:
+          return Modifier.PRIVATE;
+        case ABSTRACT:
+          return Modifier.ABSTRACT;
+        case STATIC:
+          return Modifier.STATIC;
+        case DEFAULT:
+          return Modifier.DEFAULT;
+        case FINAL:
+          return Modifier.FINAL;
+        case TRANSIENT:
+          return Modifier.TRANSIENT;
+        case VOLATILE:
+          return Modifier.VOLATILE;
+        case SYNCHRONIZED:
+          return Modifier.SYNCHRONIZED;
+        case NATIVE:
+          return Modifier.NATIVE;
+        case STRICTFP:
+          return Modifier.STRICTFP;
+        default: // fall out
+      }
+    }
+    switch (token.getTok().getText()) {
+      case "non-sealed":
+        return Modifier.valueOf("NON_SEALED");
+      case "sealed":
+        return Modifier.valueOf("SEALED");
+      default:
+        return null;
+    }
   }
 
   /** Applies replacements to the given string. */

core/src/main/java/com/google/googlejavaformat/java/java14/Java14InputAstVisitor.java

@@ -71,6 +71,16 @@ protected void handleModule(boolean first, CompilationUnitTree node) {
     }
   }
 
+  @Override
+  protected List<? extends Tree> getPermitsClause(ClassTree node) {
+    try {
+      return (List<? extends Tree>) ClassTree.class.getMethod("getPermitsClause").invoke(node);
+    } catch (ReflectiveOperationException e) {
+      // Java < 15
+      return super.getPermitsClause(node);
+    }
+  }
+
   @Override
   public Void visitBindingPattern(BindingPatternTree node, Void unused) {
     sync(node);

core/src/test/java/com/google/googlejavaformat/java/FormatterIntegrationTest.java

@@ -50,6 +50,8 @@ public class FormatterIntegrationTest {
   private static final ImmutableSet<String> JAVA14_TESTS =
       ImmutableSet.of("I477", "Records", "RSLs", "Var", "ExpressionSwitch", "I574", "I594");
 
+  private static final ImmutableSet<String> JAVA15_TESTS = ImmutableSet.of("I603");
+
   private static final ImmutableSet<String> JAVA16_TESTS = ImmutableSet.of("I588");
 
   @Parameters(name = "{index}: {0}")
@@ -92,6 +94,9 @@ public static Iterable<Object[]> data() throws IOException {
       if (JAVA14_TESTS.contains(fileName) && getMajor() < 14) {
         continue;
       }
+      if (JAVA15_TESTS.contains(fileName) && getMajor() < 15) {
+        continue;
+      }
       if (JAVA16_TESTS.contains(fileName) && getMajor() < 16) {
         continue;
       }

core/src/test/resources/com/google/googlejavaformat/java/testdata/I603.input

@@ -0,0 +1,16 @@
+class I603 {
+  sealed abstract class T1 {}
+
+  sealed class T2 extends X implements Y permits Z {}
+
+  sealed class T3
+      permits
+          Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx {}
+
+  sealed class T4
+      implements
+          Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+      permits
+          Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx,
+          Yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy {}
+}

core/src/test/resources/com/google/googlejavaformat/java/testdata/I603.output

@@ -0,0 +1,13 @@
+class I603 {
+  abstract sealed class T1 {}
+
+  sealed class T2 extends X implements Y permits Z {}
+
+  sealed class T3
+      permits Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx {}
+
+  sealed class T4
+      implements Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+      permits Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx,
+          Yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy {}
+}