feature: allow blank lines in enumConstant lists

packages/prettier-plugin-java/src/printers/classes.js

@@ -2,6 +2,7 @@
 const _ = require("lodash");
 const { line, softline, hardline } = require("prettier").doc.builders;
 const {
+  getBlankLinesSeparator,
   hasLeadingLineComments,
   reject,
   rejectAndConcat,
@@ -685,8 +686,10 @@ class ClassesPrettierVisitor {
 
   enumConstantList(ctx) {
     const enumConstants = this.mapVisit(ctx.enumConstant);
+
+    const blankLineSeparators = getBlankLinesSeparator(ctx.enumConstant);
     const commas = ctx.Comma
-      ? ctx.Comma.map(elt => concat([elt, hardline]))
+      ? ctx.Comma.map((elt, index) => concat([elt, blankLineSeparators[index]]))
       : [];
 
     return group(rejectAndJoinSeps(commas, enumConstants));

packages/prettier-plugin-java/test/unit-test/enum/_input.java

@@ -97,3 +97,21 @@ public static enum VALID_THINGS {
   }
 
 }
+
+public enum OtherEnum {
+  ONE, TWO,
+
+  THREE,
+
+
+
+  FOUR,
+  /* Five */
+  FIVE,
+
+  /* Six */
+  SIX
+
+
+}
+

packages/prettier-plugin-java/test/unit-test/enum/_output.java

@@ -115,3 +115,17 @@ public static enum VALID_THINGS {
     SECOND
   }
 }
+
+public enum OtherEnum {
+  ONE,
+  TWO,
+
+  THREE,
+
+  FOUR,
+  /* Five */
+  FIVE,
+
+  /* Six */
+  SIX
+}