[java] IDEA-296138 Join lines: join case 1:/case 2: into case 1,2:

GitOrigin-RevId: 0503a15ffcbaa37fb4c12aa769d709b8522f5020

java/java-impl/src/META-INF/JavaPlugin.xml

@@ -1189,6 +1189,7 @@
     <completion.ml.model implementation="com.intellij.codeInsight.completion.ml.JavaMLRankingProvider"/>
     <joinLinesHandler implementation="com.intellij.codeInsight.editorActions.NestedIfJoinLinesHandler"/>
     <joinLinesHandler implementation="com.intellij.codeInsight.editorActions.BlockJoinLinesHandler"/>
+    <joinLinesHandler implementation="com.intellij.codeInsight.editorActions.CaseJoinLinesHandler"/>
     <joinLinesHandler implementation="com.intellij.codeInsight.editorActions.ChainCallJoinLinesHandler"/>
     <joinLinesHandler implementation="com.intellij.codeInsight.editorActions.AssignmentSequenceJoinLinesHandler"/>
     <joinLinesHandler implementation="com.intellij.codeInsight.editorActions.DeclarationJoinLinesHandler"/>

java/java-impl/src/com/intellij/codeInsight/editorActions/CaseJoinLinesHandler.java

@@ -0,0 +1,37 @@
+// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.codeInsight.editorActions;
+
+import com.intellij.application.options.CodeStyle;
+import com.intellij.codeInsight.daemon.impl.analysis.HighlightingFeature;
+import com.intellij.lang.java.JavaLanguage;
+import com.intellij.openapi.editor.Document;
+import com.intellij.psi.*;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.psi.util.PsiUtil;
+import org.jetbrains.annotations.NotNull;
+
+public class CaseJoinLinesHandler implements JoinLinesHandlerDelegate {
+  @Override
+  public int tryJoinLines(@NotNull final Document document, @NotNull final PsiFile psiFile, final int start, final int end) {
+    if (!HighlightingFeature.ENHANCED_SWITCH.isAvailable(psiFile)) return -1;
+    PsiElement elementAtStartLineEnd = psiFile.findElementAt(start);
+    PsiElement elementAtNextLineStart = psiFile.findElementAt(end);
+    if (elementAtStartLineEnd == null || elementAtNextLineStart == null) return -1;
+    if (!PsiUtil.isJavaToken(elementAtStartLineEnd, JavaTokenType.COLON)) return -1;
+    if (!(elementAtNextLineStart instanceof PsiKeyword) ||
+        ((PsiKeyword)elementAtNextLineStart).getTokenType() != JavaTokenType.CASE_KEYWORD) {
+      return -1;
+    }
+    PsiSwitchLabelStatement firstLabel = PsiTreeUtil.getParentOfType(elementAtStartLineEnd, PsiSwitchLabelStatement.class);
+    if (firstLabel == null) return -1;
+    PsiSwitchLabelStatement secondLabel = PsiTreeUtil.getParentOfType(elementAtNextLineStart, PsiSwitchLabelStatement.class);
+    if (secondLabel == null || secondLabel == firstLabel) return -1;
+    PsiElement nextToken = PsiTreeUtil.skipWhitespacesForward(elementAtNextLineStart);
+    if (nextToken == null) return -1;
+    int replaceStart = elementAtStartLineEnd.getTextRange().getStartOffset();
+    int replaceEnd = nextToken.getTextRange().getStartOffset();
+    boolean spaceAfterComma = CodeStyle.getSettings(psiFile).getCommonSettings(JavaLanguage.INSTANCE).SPACE_AFTER_COMMA;
+    document.replaceString(replaceStart, replaceEnd, "," + (spaceAfterComma ? " " : ""));
+    return replaceStart;
+  }
+}

java/java-tests/testData/codeInsight/joinLines/CaseLabels.java

@@ -0,0 +1,12 @@
+class A {
+  void test(int x) {
+    switch (x) {
+      <selection>case 0:
+      case 1:
+      case 2:</selection>
+      case 3:
+        System.out.println("hello");
+      default:
+    }
+  }
+}

java/java-tests/testData/codeInsight/joinLines/CaseLabels2.java

@@ -0,0 +1,10 @@
+class A {
+  void test(int x) {
+    switch (x) {
+      <caret>case 0:
+      case /*hello*/ 1,2,3:
+        System.out.println("hello");
+      default:
+    }
+  }
+}

java/java-tests/testData/codeInsight/joinLines/CaseLabels2_after.java

@@ -0,0 +1,9 @@
+class A {
+  void test(int x) {
+    switch (x) {
+      case 0,/*hello*/ 1,2,3:
+        System.out.println("hello");
+      default:
+    }
+  }
+}

java/java-tests/testData/codeInsight/joinLines/CaseLabels_after.java

@@ -0,0 +1,10 @@
+class A {
+  void test(int x) {
+    switch (x) {
+      case 0, 1, 2:
+      case 3:
+        System.out.println("hello");
+      default:
+    }
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/JoinLinesTest.java

@@ -290,6 +290,13 @@ public class JoinLinesTest extends LightJavaCodeInsightTestCase {
   public void testJoinFields2() {doTest(3);}
   public void testJoinFields3() {doTest();}
 
+  public void testCaseLabels() {doTest();}
+  public void testCaseLabels2() {
+    CommonCodeStyleSettings settings = getJavaSettings();
+    settings.SPACE_AFTER_COMMA = false;
+    doTest();
+  }
+
   private void doTest() {
     doTest(".java");
   }