Wrap multiple values in switch expression case

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

@@ -177,7 +177,7 @@ boolean isYes() {
   }
 
   /** Whether to collapse empty blocks. */
-  enum CollapseEmptyOrNot {
+  protected enum CollapseEmptyOrNot {
     YES,
     NO;
 
@@ -191,7 +191,7 @@ boolean isYes() {
   }
 
   /** Whether to allow leading blank lines in blocks. */
-  enum AllowLeadingBlankLine {
+  protected enum AllowLeadingBlankLine {
     YES,
     NO;
 
@@ -201,7 +201,7 @@ static AllowLeadingBlankLine valueOf(boolean b) {
   }
 
   /** Whether to allow trailing blank lines in blocks. */
-  enum AllowTrailingBlankLine {
+  protected enum AllowTrailingBlankLine {
     YES,
     NO;
 
@@ -2097,7 +2097,7 @@ void visitAnnotations(
   }
 
   /** Helper method for blocks. */
-  private void visitBlock(
+  protected void visitBlock(
       BlockTree node,
       CollapseEmptyOrNot collapseEmptyOrNot,
       AllowLeadingBlankLine allowLeadingBlankLine,

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

@@ -22,6 +22,7 @@
 import com.google.googlejavaformat.OpsBuilder;
 import com.google.googlejavaformat.java.JavaInputAstVisitor;
 import com.sun.source.tree.BindingPatternTree;
+import com.sun.source.tree.BlockTree;
 import com.sun.source.tree.CaseTree;
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.ExpressionTree;
@@ -214,16 +215,18 @@ public Void visitCase(CaseTree node, Void unused) {
       token("default", plusTwo);
     } else {
       token("case", plusTwo);
+      builder.open(plusFour);
       builder.space();
       boolean first = true;
       for (ExpressionTree expression : node.getExpressions()) {
         if (!first) {
           token(",");
-          builder.space();
+          builder.breakOp(" ");
         }
         scan(expression, null);
         first = false;
       }
+      builder.close();
     }
     switch (node.getCaseKind()) {
       case STATEMENT:
@@ -237,7 +240,16 @@ public Void visitCase(CaseTree node, Void unused) {
         token("-");
         token(">");
         builder.space();
-        scan(node.getBody(), null);
+        if (node.getBody().getKind() == Tree.Kind.BLOCK) {
+          // Explicit call with {@link CollapseEmptyOrNot.YES} to handle empty case blocks.
+          visitBlock(
+                (BlockTree) node.getBody(),
+                CollapseEmptyOrNot.YES,
+                AllowLeadingBlankLine.NO,
+                AllowTrailingBlankLine.NO);
+        } else {
+          scan(node.getBody(), null);
+        }
         builder.guessToken(";");
         break;
       default:

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

@@ -25,4 +25,17 @@ class ExpressionSwitch {
       default -> System.out.println("default");
     }
   }
+
+  String breakLongCaseArgs(MyEnum e) {
+    return switch (e) {
+      case SOME_RATHER_LONG_NAME_1, SOME_RATHER_LONG_NAME_2, SOME_RATHER_LONG_NAME_3, SOME_RATHER_LONG_NAME_4, SOME_RATHER_LONG_NAME_5, SOME_RATHER_LONG_NAME_6, SOME_RATHER_LONG_NAME_7 -> {}
+      case SOME_RATHER_LONG_NAME_8 -> {}
+    };
+  }
+
+  String dontBreakShortCaseArgs(MyEnum e) {
+    return switch (e) {
+      case CASE_A, CASE_B -> {}
+    };
+  }
 }

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

@@ -31,4 +31,23 @@ class ExpressionSwitch {
       default -> System.out.println("default");
     }
   }
+
+  String breakLongCaseArgs(MyEnum e) {
+    return switch (e) {
+      case SOME_RATHER_LONG_NAME_1,
+          SOME_RATHER_LONG_NAME_2,
+          SOME_RATHER_LONG_NAME_3,
+          SOME_RATHER_LONG_NAME_4,
+          SOME_RATHER_LONG_NAME_5,
+          SOME_RATHER_LONG_NAME_6,
+          SOME_RATHER_LONG_NAME_7 -> {}
+      case SOME_RATHER_LONG_NAME_8 -> {}
+    };
+  }
+
+  String dontBreakShortCaseArgs(MyEnum e) {
+    return switch (e) {
+      case CASE_A, CASE_B -> {}
+    };
+  }
 }