Issue #2818: Add support for lambda expression in LeftCurlyCheck

src/main/java/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheck.java

@@ -40,7 +40,8 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
  * LITERAL_IF},  {@link TokenTypes#LITERAL_SWITCH LITERAL_SWITCH},  {@link
  * TokenTypes#LITERAL_SYNCHRONIZED LITERAL_SYNCHRONIZED},  {@link
  * TokenTypes#LITERAL_TRY LITERAL_TRY},  {@link TokenTypes#LITERAL_WHILE
- * LITERAL_WHILE},  {@link TokenTypes#STATIC_INIT STATIC_INIT}.
+ * LITERAL_WHILE},  {@link TokenTypes#STATIC_INIT STATIC_INIT},
+ * {@link TokenTypes#LAMBDA LAMBDA}.
  * </p>
  *
  * <p>
@@ -167,6 +168,7 @@ public class LeftCurlyCheck
             TokenTypes.LITERAL_FOR,
             TokenTypes.STATIC_INIT,
             TokenTypes.OBJBLOCK,
+            TokenTypes.LAMBDA,
         };
     }
 
@@ -208,6 +210,7 @@ public class LeftCurlyCheck
             case TokenTypes.LITERAL_DO:
             case TokenTypes.LITERAL_IF:
             case TokenTypes.STATIC_INIT:
+            case TokenTypes.LAMBDA:
                 startToken = ast;
                 brace = ast.findFirstToken(TokenTypes.SLIST);
                 break;

src/test/java/com/puppycrawl/tools/checkstyle/checks/blocks/LeftCurlyCheckTest.java

@@ -51,6 +51,12 @@ public class LeftCurlyCheckTest extends BaseCheckTestSupport {
                 + "blocks" + File.separator + filename);
     }
 
+    @Override
+    protected String getNonCompilablePath(String filename) throws IOException {
+        return super.getNonCompilablePath("checks" + File.separator
+                + "blocks" + File.separator + filename);
+    }
+
     /* Additional test for jacoco, since valueOf()
      * is generated by javac and jacoco reports that
      * valueOf() is uncovered.
@@ -280,6 +286,28 @@ public class LeftCurlyCheckTest extends BaseCheckTestSupport {
         verify(checkConfig, getPath("InputLeftCurlyEnums.java"), expectedWhileFalse);
     }
 
+    @Test
+    public void testDefaultLambda() throws Exception {
+        final String[] expected = {
+            "5:1: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 1),
+            "12:32: " + getCheckMessage(MSG_KEY_LINE_BREAK_AFTER, "{", 32),
+            "15:5: " + getCheckMessage(MSG_KEY_LINE_PREVIOUS, "{", 5),
+        };
+        verify(checkConfig, getNonCompilablePath("InputLeftCurlyNewLineOptionWithLambda.java"),
+                expected);
+    }
+
+    @Test
+    public void testNewLineOptionWithLambda() throws Exception {
+        checkConfig.addAttribute("option", LeftCurlyOption.NL.toString());
+        final String[] expected = {
+            "6:32: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 32),
+            "12:32: " + getCheckMessage(MSG_KEY_LINE_NEW, "{", 32),
+        };
+        verify(checkConfig, getNonCompilablePath("InputLeftCurlyNewLineOptionWithLambda.java"),
+                expected);
+    }
+
     @Test
     public void testGetAcceptableTokens() {
         final LeftCurlyCheck check = new LeftCurlyCheck();
@@ -303,7 +331,8 @@ public class LeftCurlyCheckTest extends BaseCheckTestSupport {
             TokenTypes.LITERAL_ELSE,
             TokenTypes.LITERAL_FOR,
             TokenTypes.STATIC_INIT,
-            TokenTypes.OBJBLOCK, };
+            TokenTypes.OBJBLOCK,
+            TokenTypes.LAMBDA, };
         assertArrayEquals(expected, actual);
     }
 

src/test/resources-noncompilable/com/puppycrawl/tools/checkstyle/checks/blocks/InputLeftCurlyNewLineOptionWithLambda.java

@@ -0,0 +1,18 @@
+//Compilable with Java8
+package com.puppycrawl.tools.checkstyle.checks.blocks;
+
+public class InputLeftCurlyNewLineOptionWithLambda
+{
+    static Runnable r1 = () -> {
+        System.out.println("Hello world one!");
+    };
+
+    static Runnable r2 = () -> System.out.println("Hello world two!");
+
+    static Runnable r3 = () -> {System.out.println("Hello world two!");};
+
+    static Runnable r4 = () ->
+    {
+        System.out.println("Hello world one!");
+    };
+}

src/xdocs/config_blocks.xml

@@ -471,7 +471,8 @@ try {
               <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_ELSE">LITERAL_ELSE</a>,
               <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_FOR">LITERAL_FOR</a>,
               <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STATIC_INIT">STATIC_INIT</a>,
-              <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#OBJBLOCK">OBJBLOCK</a>.
+              <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#OBJBLOCK">OBJBLOCK</a>,
+              <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">LAMBDA</a>.
             </td>
 
             <td>
@@ -493,7 +494,8 @@ try {
               <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_ELSE">LITERAL_ELSE</a>,
               <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_FOR">LITERAL_FOR</a>,
               <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#STATIC_INIT">STATIC_INIT</a>,
-              <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#OBJBLOCK">OBJBLOCK</a>.
+              <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#OBJBLOCK">OBJBLOCK</a>,
+              <a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">LAMBDA</a>.
             </td>
           </tr>
         </table>