fix: improve throws formatting

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

@@ -15,6 +15,7 @@ import {
 import {
  concat,
  group,
+ ifBreak,
  indent,
  join,
  indentIfBreak
@@ -515,18 +516,23 @@ export class ClassesPrettierVisitor extends BaseCstPrettierPrinter {
 
  methodDeclaration(ctx: MethodDeclarationCtx) {
  const modifiers = sortModifiers(ctx.methodModifier);
+ const throwsGroupId = Symbol("throws");
  const firstAnnotations = this.mapVisit(modifiers[0]);
  const otherModifiers = this.mapVisit(modifiers[1]);
 
- const header = this.visit(ctx.methodHeader);
+ const header = this.visit(ctx.methodHeader, { throwsGroupId });
  const body = this.visit(ctx.methodBody);
 
- const headerBodySeparator = isStatementEmptyStatement(body) ? "" : " ";
+ const headerBodySeparator = isStatementEmptyStatement(body)
+ ? ""
+ : ctx.methodHeader[0].children.throws
+ ? ifBreak(hardline, " ", { groupId: throwsGroupId })
+ : " ";
 
  return rejectAndJoin(hardline, [
- rejectAndJoin(hardline, firstAnnotations),
+ ...firstAnnotations,
  rejectAndJoin(" ", [
- rejectAndJoin(" ", otherModifiers),
+ ...otherModifiers,
  rejectAndJoin(headerBodySeparator, [header, body])
  ])
  ]);
@@ -540,12 +546,12 @@ export class ClassesPrettierVisitor extends BaseCstPrettierPrinter {
  return printTokenWithComments(this.getSingle(ctx) as IToken);
  }
 
- methodHeader(ctx: MethodHeaderCtx) {
+ methodHeader(ctx: MethodHeaderCtx, opts: { throwsGroupId: symbol }) {
  const typeParameters = this.visit(ctx.typeParameters);
  const annotations = this.mapVisit(ctx.annotation);
  const result = this.visit(ctx.result);
  const declarator = this.visit(ctx.methodDeclarator);
- const throws = this.visit(ctx.throws);
+ const throws = this.visit(ctx.throws, opts);
 
  return group(
  concat([
@@ -652,15 +658,16 @@ export class ClassesPrettierVisitor extends BaseCstPrettierPrinter {
  return printTokenWithComments(this.getSingle(ctx) as IToken);
  }
 
- throws(ctx: ThrowsCtx) {
+ throws(ctx: ThrowsCtx, opts: { throwsGroupId: symbol }) {
  const exceptionTypeList = this.visit(ctx.exceptionTypeList);
- const throwsDeclaration = join(" ", [ctx.Throws[0], exceptionTypeList]);
- return group(indent(rejectAndConcat([softline, throwsDeclaration])));
+ return group(indent(join(line, [ctx.Throws[0], exceptionTypeList])), {
+ id: opts.throwsGroupId
+ });
  }
 
  exceptionTypeList(ctx: ExceptionTypeListCtx) {
  const exceptionTypes = this.mapVisit(ctx.exceptionType);
- const commas = ctx.Comma ? ctx.Comma.map(elt => concat([elt, " "])) : [];
+ const commas = ctx.Comma?.map(comma => concat([comma, line]));
  return rejectAndJoinSeps(commas, exceptionTypes);
  }
 
@@ -687,25 +694,26 @@ export class ClassesPrettierVisitor extends BaseCstPrettierPrinter {
  }
 
  constructorDeclaration(ctx: ConstructorDeclarationCtx) {
+ const throwsGroupId = Symbol("throws");
  const modifiers = sortModifiers(ctx.constructorModifier);
  const firstAnnotations = this.mapVisit(modifiers[0]);
  const otherModifiers = this.mapVisit(modifiers[1]);
-
  const constructorDeclarator = this.visit(ctx.constructorDeclarator);
- const throws = this.visit(ctx.throws);
+ const throws = this.visit(ctx.throws, { throwsGroupId });
  const constructorBody = this.visit(ctx.constructorBody);
 
- return rejectAndJoin(" ", [
+ return concat([
  group(
  rejectAndJoin(hardline, [
  rejectAndJoin(hardline, firstAnnotations),
  rejectAndJoin(" ", [
- join(" ", otherModifiers),
+ rejectAndJoin(" ", otherModifiers),
  constructorDeclarator,
  throws
  ])
  ])
  ),
+ ctx.throws ? ifBreak(hardline, " ", { groupId: throwsGroupId }) : " ",
  constructorBody
  ]);
  }

packages/prettier-plugin-java/src/printers/interfaces.ts

@@ -1,4 +1,4 @@
-import { concat, group, indent } from "./prettier-builder.js";
+import { concat, group, ifBreak, indent } from "./prettier-builder.js";
 import { printTokenWithComments } from "./comments/format-comments.js";
 import {
  displaySemicolon,
@@ -175,12 +175,17 @@ export class InterfacesPrettierVisitor extends BaseCstPrettierPrinter {
 
  interfaceMethodDeclaration(ctx: InterfaceMethodDeclarationCtx) {
  const modifiers = sortModifiers(ctx.interfaceMethodModifier);
+ const throwsGroupId = Symbol("throws");
  const firstAnnotations = this.mapVisit(modifiers[0]);
  const otherModifiers = this.mapVisit(modifiers[1]);
 
- const methodHeader = this.visit(ctx.methodHeader);
+ const methodHeader = this.visit(ctx.methodHeader, { throwsGroupId });
  const methodBody = this.visit(ctx.methodBody);
- const separator = isStatementEmptyStatement(methodBody) ? "" : " ";
+ const separator = isStatementEmptyStatement(methodBody)
+ ? ""
+ : ctx.methodHeader[0].children.throws
+ ? ifBreak(hardline, " ", { groupId: throwsGroupId })
+ : " ";
 
  return rejectAndJoin(hardline, [
  rejectAndJoin(hardline, firstAnnotations),

packages/prettier-plugin-java/src/printers/prettier-builder.ts

@@ -53,11 +53,13 @@ export function dedent(doc: Doc | IToken) {
 
 export function ifBreak(
  breakContents: Doc | IToken,
- flatContents: Doc | IToken
+ flatContents: Doc | IToken,
+ options?: { groupId?: symbol | undefined }
 ) {
  return builders.ifBreak(
  processComments(breakContents),
- processComments(flatContents)
+ processComments(flatContents),
+ options
  );
 }
 

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

@@ -87,3 +87,55 @@ public Throws(String string1, String string2, String string3, String string4, St
  System.out.println("Constructor with throws that should wrap");
  }
 }
+
+interface Example {
+ void example1(String arg1, String arg2)
+ throws RuntimeException, RuntimeException, RuntimeException, RuntimeException;
+
+ void example2(
+ String arg1,
+ String arg2,
+ String arg3,
+ String arg4,
+ String arg5,
+ String arg6
+ ) throws RuntimeException, RuntimeException, RuntimeException;
+
+ void example3(
+ String arg1,
+ String arg2,
+ String arg3,
+ String arg4,
+ String arg5,
+ String arg6
+ )
+ throws RuntimeException, RuntimeException, RuntimeException, RuntimeException;
+
+ default void example1(String arg1, String arg2)
+ throws RuntimeException, RuntimeException, RuntimeException, RuntimeException {
+ throw new RuntimeException();
+ }
+
+ default void example2(
+ String arg1,
+ String arg2,
+ String arg3,
+ String arg4,
+ String arg5,
+ String arg6
+ ) throws RuntimeException, RuntimeException, RuntimeException {
+ throw new RuntimeException();
+ }
+
+ default void example3(
+ String arg1,
+ String arg2,
+ String arg3,
+ String arg4,
+ String arg5,
+ String arg6
+ )
+ throws RuntimeException, RuntimeException, RuntimeException, RuntimeException {
+ throw new RuntimeException();
+ }
+}