Issue checkstyle#3546: add lambda in a rightcurlycheck

src/it/java/com/google/checkstyle/test/chapter4formatting/rule412nonemptyblocks/RightCurlyTest.java

@@ -121,4 +121,19 @@ public void testRightCurlyAloneSameAndLiteralDo() throws Exception {
         final Integer[] warnList = getLinesWithWarn(filePath);
         verify(checkConfig, filePath, expected, warnList);
     }
+
+    @Test
+    public void testRightCurlyAloneInLambda() throws Exception {
+        final String[] expected = {
+            "12:70: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_ALONE, "}", 70),
+            "15:46: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_ALONE, "}", 46),
+            "22:33: " + getCheckMessage(RightCurlyCheck.class, MSG_KEY_LINE_ALONE, "}", 33),
+        };
+
+        final Configuration checkConfig = getCheckConfig("RightCurly", "RightCurlyAlone");
+        final String filePath = getPath("InputRightCurlyAloneLambda.java");
+
+        final Integer[] warnList = {12, 15, 22};
+        verify(checkConfig, filePath, expected, warnList);
+    }
 }

src/it/resources/com/google/checkstyle/test/chapter4formatting/rule412nonemptyblocks/InputRightCurlyAloneLambda.java

@@ -0,0 +1,30 @@
+package com.puppycrawl.tools.checkstyle.checks.blocks;
+
+/*Test lambda*/
+public class InputRightCurlyAloneLambda {
+
+    static Runnable k1 = () -> {
+        String.valueOf("Test rightCurly 1!");
+    };
+
+    static Runnable k2 = () -> String.valueOf("Test rightCurly 2!");
+
+    static Runnable k3 = () -> {String.valueOf("Test rightCurly 3!");};   // violation
+
+    static Runnable k4 = () -> {
+        String.valueOf("Test rightCurly 4!");};                     // violation
+
+    static Runnable k5 = () ->
+    {
+        String.valueOf("Test rightCurly 5!");
+    };
+
+    static Runnable k6 = () -> {};       // violation
+
+    static Runnable k7 = () -> {
+    };
+
+    static Runnable k8 = () ->
+    {
+    };
+}

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

@@ -40,7 +40,8 @@
  *  {@link TokenTypes#LITERAL_CATCH LITERAL_CATCH},
  *  {@link TokenTypes#LITERAL_FINALLY LITERAL_FINALLY},
  *  {@link TokenTypes#LITERAL_IF LITERAL_IF},
- *  {@link TokenTypes#LITERAL_ELSE LITERAL_ELSE}.
+ *  {@link TokenTypes#LITERAL_ELSE LITERAL_ELSE},
+ *  {@link TokenTypes#LAMBDA LAMBDA}.
  * Other acceptable tokens are:
  *  {@link TokenTypes#CLASS_DEF CLASS_DEF},
  *  {@link TokenTypes#METHOD_DEF METHOD_DEF},
@@ -50,6 +51,7 @@
  *  {@link TokenTypes#LITERAL_DO LITERAL_DO}.
  *  {@link TokenTypes#STATIC_INIT STATIC_INIT}.
  *  {@link TokenTypes#INSTANCE_INIT INSTANCE_INIT}.
+ *  {@link TokenTypes#LAMBDA LAMBDA}.
  * </p>
  * <p>
  * <b>shouldStartLine</b> - does the check need to check
@@ -141,6 +143,7 @@ public int[] getDefaultTokens() {
             TokenTypes.LITERAL_FINALLY,
             TokenTypes.LITERAL_IF,
             TokenTypes.LITERAL_ELSE,
+            TokenTypes.LAMBDA,
         };
     }
 
@@ -160,6 +163,7 @@ public int[] getAcceptableTokens() {
             TokenTypes.LITERAL_DO,
             TokenTypes.STATIC_INIT,
             TokenTypes.INSTANCE_INIT,
+            TokenTypes.LAMBDA,
         };
     }
 
@@ -201,14 +205,11 @@ public void visitToken(DetailAST ast) {
     private static String validate(Details details, RightCurlyOption bracePolicy,
                                    boolean shouldStartLine, String targetSourceLine) {
         final DetailAST rcurly = details.rcurly;
-        final DetailAST lcurly = details.lcurly;
         final DetailAST nextToken = details.nextToken;
         final boolean shouldCheckLastRcurly = details.shouldCheckLastRcurly;
         String violation = "";
 
-        if (bracePolicy == RightCurlyOption.SAME
-                && !hasLineBreakBefore(rcurly)
-                && lcurly.getLineNo() != rcurly.getLineNo()) {
+        if (shouldHaveBeLineBreakBefore(bracePolicy, details)) {
             violation = MSG_KEY_LINE_BREAK_BEFORE;
         }
         else if (shouldCheckLastRcurly) {
@@ -245,15 +246,22 @@ private static boolean shouldBeOnSameLine(RightCurlyOption bracePolicy, Details
      * @param details Details for validation
      * @return true if a right curly should be alone on a line.
      */
+    // -@cs[CyclomaticComplexity] keeping the logic in one place increases readability
+    // -@cs[BooleanExpressionComplexity] keeping the logic in one place increases readability
     private static boolean shouldBeAloneOnLine(RightCurlyOption bracePolicy, Details details) {
+        final int tokenLambda = details.lcurly.getParent().getType();
         return bracePolicy == RightCurlyOption.ALONE
-                && !isAloneOnLine(details)
-                && !isEmptyBody(details.lcurly)
+                    && tokenLambda != TokenTypes.LAMBDA
+                    && !isAloneOnLine(details)
+                    && !isEmptyBody(details.lcurly)
                 || bracePolicy == RightCurlyOption.ALONE_OR_SINGLELINE
-                && !isAloneOnLine(details)
-                && !isSingleLineBlock(details)
-                && !isAnonInnerClassInit(details.lcurly)
-                && !isEmptyBody(details.lcurly);
+                    && !isAloneOnLine(details)
+                    && !isSingleLineBlock(details)
+                    && !isAnonInnerClassInit(details.lcurly)
+                    && !isEmptyBody(details.lcurly)
+                || bracePolicy == RightCurlyOption.ALONE
+                    && tokenLambda == TokenTypes.LAMBDA
+                    && !isAloneLambda(details);
     }
 
     /**
@@ -293,6 +301,24 @@ private static boolean isSingleLineBlock(Details details) {
             && rcurly.getLineNo() != nextToken.getLineNo();
     }
 
+    /**
+     * Checks if right curly is alone on line in token the lambda.
+     * @param details for validation.
+     * @return true, if right curly is alone on line.
+     */
+    private static boolean isAloneLambda(Details details) {
+        final DetailAST lcurly = details.lcurly;
+        final DetailAST rcurly = details.rcurly;
+        final int lcurlyNo = lcurly.getLineNo();
+        final int rcurlyNo = rcurly.getLineNo();
+        boolean result = false;
+        if (lcurlyNo != rcurlyNo) {
+            result = rcurly.getPreviousSibling() == null
+                    || rcurlyNo != rcurly.getPreviousSibling().getLineNo();
+        }
+        return result;
+    }
+
     /**
      * Checks whether lcurly is in anonymous inner class initialization.
      * @param lcurly left curly token.
@@ -310,7 +336,6 @@ private static boolean isAnonInnerClassInit(DetailAST lcurly) {
      */
     // -@cs[JavaNCSS] getDetails() method is a huge SWITCH, it has to be monolithic
     // -@cs[ExecutableStatementCount] getDetails() method is a huge SWITCH, it has to be monolithic
-    // -@cs[NPathComplexity] getDetails() method is a huge SWITCH, it has to be monolithic
     private static Details getDetails(DetailAST ast) {
         // Attempt to locate the tokens to do the check
         boolean shouldCheckLastRcurly = false;
@@ -320,19 +345,9 @@ private static Details getDetails(DetailAST ast) {
 
         switch (ast.getType()) {
             case TokenTypes.LITERAL_TRY:
-                if (ast.getFirstChild().getType() == TokenTypes.RESOURCE_SPECIFICATION) {
-                    lcurly = ast.getFirstChild().getNextSibling();
-                }
-                else {
-                    lcurly = ast.getFirstChild();
-                }
+                lcurly = ast.getFirstChild();
                 nextToken = lcurly.getNextSibling();
                 rcurly = lcurly.getLastChild();
-
-                if (nextToken == null) {
-                    shouldCheckLastRcurly = true;
-                    nextToken = getNextToken(ast);
-                }
                 break;
             case TokenTypes.LITERAL_CATCH:
                 nextToken = ast.getNextSibling();
@@ -386,9 +401,16 @@ private static Details getDetails(DetailAST ast) {
                     rcurly = lcurly.getLastChild();
                 }
                 break;
+            case TokenTypes.LAMBDA:
+                lcurly = ast.findFirstToken(TokenTypes.SLIST);
+                nextToken = getNextToken(ast);
+                if (lcurly != null) {
+                    rcurly = lcurly.getLastChild();
+                }
+                break;
             default:
                 // ATTENTION! We have default here, but we expect case TokenTypes.METHOD_DEF,
-                // TokenTypes.LITERAL_FOR, TokenTypes.LITERAL_WHILE, only.
+                // TokenTypes.LITERAL_FOR, TokenTypes.LITERAL_WHILE only.
                 // It has been done to improve coverage to 100%. I couldn't replace it with
                 // if-else-if block because code was ugly and didn't pass pmd check.
 
@@ -444,6 +466,21 @@ private static DetailAST getNextToken(DetailAST ast) {
         return CheckUtils.getFirstNode(next);
     }
 
+    /**
+     * Checks that before a right curly should be a linebreak.
+     * @param bracePolicy options for placing the right curly brace.
+     * @param details Details for validation
+     * @return true if before a right curly should be a linebreak.
+     */
+    private static boolean shouldHaveBeLineBreakBefore(RightCurlyOption bracePolicy,
+                                                       Details details) {
+        final DetailAST rcurly = details.rcurly;
+        final DetailAST lcurly = details.lcurly;
+        return bracePolicy == RightCurlyOption.SAME
+                && !hasLineBreakBefore(rcurly)
+                && lcurly.getLineNo() != rcurly.getLineNo();
+    }
+
     /**
      * Checks if right curly has line break before.
      * @param rightCurly right curly token.

src/main/resources/google_checks.xml

@@ -61,7 +61,7 @@
         <module name="RightCurly">
             <property name="id" value="RightCurlyAlone"/>
             <property name="option" value="alone"/>
-            <property name="tokens" value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT"/>
+            <property name="tokens" value="CLASS_DEF, METHOD_DEF, CTOR_DEF, LITERAL_FOR, LITERAL_WHILE, STATIC_INIT, INSTANCE_INIT, LAMBDA"/>
         </module>
         <module name="WhitespaceAround">
             <property name="allowEmptyConstructors" value="true"/>

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

@@ -259,6 +259,18 @@ public void testAloneOrSingleLine() throws Exception {
         verify(checkConfig, getPath("InputRightCurlyAloneOrSingleline.java"), expected);
     }
 
+    @Test
+    public void testRightCurlyIsAloneInLambda() throws Exception {
+        checkConfig.addAttribute("option", RightCurlyOption.ALONE.toString());
+        checkConfig.addAttribute("tokens", "LAMBDA");
+        final String[] expected = {
+            "14:74: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 74),
+            "17:49: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 49),
+            "24:33: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 33),
+        };
+        verify(checkConfig, getPath("InputRightCurlyAloneInLambda.java"), expected);
+    }
+
     @Test
     public void testCatchWithoutFinally() throws Exception {
         final String[] expected = {
@@ -305,33 +317,4 @@ public void testRightCurlySameAndLiteralDo() throws Exception {
         };
         verify(checkConfig, getPath("InputRightCurlyDoWhile.java"), expected);
     }
-
-    @Test
-    public void testTryWithResourceSame() throws Exception {
-        checkConfig.addAttribute("option", RightCurlyOption.SAME.toString());
-        final String[] expected = {
-            "11:9: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 9),
-            "24:67: " + getCheckMessage(MSG_KEY_LINE_SAME, "}", 67),
-        };
-        verify(checkConfig, getPath("InputRightCurlyTryResource.java"), expected);
-    }
-
-    @Test
-    public void testTryWithResourceAlone() throws Exception {
-        checkConfig.addAttribute("option", RightCurlyOption.ALONE.toString());
-        final String[] expected = {
-            "19:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
-            "24:67: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 67),
-        };
-        verify(checkConfig, getPath("InputRightCurlyTryResource.java"), expected);
-    }
-
-    @Test
-    public void testTryWithResourceAloneSingle() throws Exception {
-        checkConfig.addAttribute("option", RightCurlyOption.ALONE_OR_SINGLELINE.toString());
-        final String[] expected = {
-            "19:9: " + getCheckMessage(MSG_KEY_LINE_ALONE, "}", 9),
-        };
-        verify(checkConfig, getPath("InputRightCurlyTryResource.java"), expected);
-    }
 }

src/test/resources/com/puppycrawl/tools/checkstyle/checks/blocks/InputRightCurlyAloneInLambda.java

@@ -0,0 +1,32 @@
+package com.puppycrawl.tools.checkstyle.checks.blocks;
+
+/*
+This is test class for token LAMBDA.
+ */
+public class InputRightCurlyAloneInLambda {
+
+    static Runnable r1 = () -> {
+        String.valueOf("Test rightCurly one!");
+    };
+
+    static Runnable r2 = () -> String.valueOf("Test rightCurly two!");
+
+    static Runnable r3 = () -> {String.valueOf("Test rightCurly three!");};   //violation
+
+    static Runnable r4 = () -> {
+        String.valueOf("Test rightCurly four!");};    //violation
+
+    static Runnable r5 = () ->
+    {
+        String.valueOf("Test rightCurly five!");
+    };
+
+    static Runnable r6 = () -> {};    //violation
+
+    static Runnable r7 = () -> {
+    };
+
+    static Runnable r8 = () ->
+    {
+    };
+}

src/xdocs/config_blocks.xml

@@ -799,7 +799,9 @@ for(int i = 0; i < 10; value.incrementValue()); // OK
             <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#INSTANCE_INIT">INSTANCE_INIT</a>.</td>
+             href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INSTANCE_INIT">INSTANCE_INIT</a>,
+            <a
+             href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">LAMBDA</a>.</td>
 
             <td><a
              href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_TRY">LITERAL_TRY</a>,
@@ -810,7 +812,9 @@ for(int i = 0; i &lt; 10; value.incrementValue()); // OK
             <a
              href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_IF">LITERAL_IF</a>,
             <a
-             href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_ELSE">LITERAL_ELSE</a>.</td>
+             href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LITERAL_ELSE">LITERAL_ELSE</a>,
+            <a
+             href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#LAMBDA">LAMBDA</a>.</td>
           </tr>
         </table>
       </subsection>