Rationale: Putting this comma in makes is easier to change the order of the elements or add + * new elements at the end of the list. This is similar to + * ArrayTrailingComma. + * + *
The following is a normal enum type declaration: + *
+ * enum Type {
+ * ALPHA,
+ * BETA,
+ * GAMMA
+ * }
+ *
+ *
+ * However, if you want to append something to the list, you would need to change the line + * containing the last enum constant: + * + *
+ * enum Type {
+ * ALPHA,
+ * BETA,
+ * GAMMA, // changed due to the ','
+ * DELTA // new line
+ * }
+ *
+ *
+ * This check makes sure that also the last enum constant has a trailing comma, which is + * valid according to the Java Spec (see Enum Constants) + * + *
+ * enum Type {
+ * ALPHA,
+ * BETA,
+ * GAMMA,
+ * DELTA, // removing this comma will result in a violation with the check activated
+ * }
+ *
+ *
+ * However, you could also add a semicolon behind that comma on the same line, which would raise + * a violation + * + *
+ * enum Type {
+ * ALPHA,
+ * BETA,
+ * GAMMA,
+ * DELTA,; // violation
+ * }
+ *
+ * In this case the semicolon should be removed. However, if there is more in the enum body, the
+ * semicolon should be placed on a line by itself.
+ *
+ * An example of how to configure the check is: + *
+ * <module name="EnumTrailingComma"/> + *+ * + *
Please note that using this check together with {@code NoWhitespaceBefore} or
+ * {@code SeparatorWrap} may create conflicts with enums that contain a body:
+ * {@code EnumTrailingComma} enforces the semicolon on a separate line while
+ * {@code NoWhiteSpaceBefore} does not allow the semicolon to be preceded with whitespace and
+ * {@code SeparatorWrap} expects the semicolon to be on the same line as the last enum constant.
+ *
+ * @author Kariem Hussein
+ */
+public class EnumTrailingCommaCheck extends AbstractCheck {
+
+ /** Key for warning message text in "messages.properties" file. */
+ public static final String MSG_KEY = "enum.trailing.comma";
+
+ @Override
+ public int[] getDefaultTokens() {
+ return getAcceptableTokens();
+ }
+
+ @Override
+ public int[] getAcceptableTokens() {
+ return new int[] {TokenTypes.ENUM_DEF};
+ }
+
+ @Override
+ public int[] getRequiredTokens() {
+ return getAcceptableTokens();
+ }
+
+ @Override
+ public void visitToken(DetailAST enumDef) {
+ final DetailAST enumConstBlock = enumDef.findFirstToken(TokenTypes.OBJBLOCK);
+
+ final DetailAST enumConstLeft = enumConstBlock.findFirstToken(TokenTypes.LCURLY);
+ final DetailAST enumConstRight = enumConstBlock.findFirstToken(TokenTypes.RCURLY);
+
+ // Only check, if block is multi-line and there are more than one enum constants
+ if (enumConstLeft.getLineNo() != enumConstRight.getLineNo()
+ && enumConstBlock.getChildCount(TokenTypes.ENUM_CONSTANT_DEF) > 1) {
+ final DetailAST constant = enumConstBlock.findFirstToken(TokenTypes.ENUM_CONSTANT_DEF);
+ final DetailAST lastComma = getLastComma(constant);
+
+ final DetailAST nextAst = lastComma.getNextSibling();
+ if (isIllegalTokenAfterComma(lastComma, nextAst)) {
+ log(nextAst, MSG_KEY);
+ }
+ }
+ }
+
+ /**
+ * Check whether there is an illegal token after the last comma token.
+ *
+ * @param lastComma the AST containing the last comma
+ * @param nextAst the next AST
+ * @return {@code true} if there is an illegal token after the last comma,
+ * {@code false} otherwise
+ */
+ private boolean isIllegalTokenAfterComma(DetailAST lastComma, DetailAST nextAst) {
+ final int nextAstType = nextAst.getType();
+
+ // semi on the same line as last comma, or followed by enum constant
+ return (nextAstType == TokenTypes.SEMI && nextAst.getLineNo() == lastComma.getLineNo())
+ || nextAstType == TokenTypes.ENUM_CONSTANT_DEF;
+ }
+
+ /**
+ * Get the last comma in a series of siblings.
+ *
+ * @param start the first sibling
+ * @return the AST containing the last comma
+ */
+ private static DetailAST getLastComma(DetailAST start) {
+ DetailAST comma = null;
+ for (DetailAST ast = start; ast != null; ast = ast.getNextSibling()) {
+ if (ast.getType() == TokenTypes.COMMA) {
+ comma = ast;
+ }
+ }
+ return comma;
+ }
+}
diff --git a/sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/NumericLiteralNeedsUnderscoreCheck.java b/sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/NumericLiteralNeedsUnderscoreCheck.java
index be23a6fdf3..a3821a152e 100644
--- a/sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/NumericLiteralNeedsUnderscoreCheck.java
+++ b/sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/NumericLiteralNeedsUnderscoreCheck.java
@@ -166,7 +166,7 @@ protected enum NumericType {
/**
* Denotes a binary literal. For example, 0b0011
*/
- BINARY;
+ BINARY,
}
diff --git a/sevntu-checks/src/main/resources/com/github/sevntu/checkstyle/checks/coding/messages.properties b/sevntu-checks/src/main/resources/com/github/sevntu/checkstyle/checks/coding/messages.properties
index 04ee0a0026..9427dcc5ad 100644
--- a/sevntu-checks/src/main/resources/com/github/sevntu/checkstyle/checks/coding/messages.properties
+++ b/sevntu-checks/src/main/resources/com/github/sevntu/checkstyle/checks/coding/messages.properties
@@ -12,8 +12,9 @@ custom.declaration.order.interface=Interface definition in wrong order. Expected
custom.declaration.order.enum=Enum definition in wrong order. Expected ''{0}'' then ''{1}''.
custom.declaration.order.invalid.setter=Setter ''{0}'' is in wrong order. Should be right after ''{1}''.
diamond.operator.for.variable.definition = Diamond operator expected.
-empty.public.ctor=This empty public constructor is useless.
either.log.or.throw=Either log or throw exception.
+empty.public.ctor=This empty public constructor is useless.
+enum.trailing.comma=Enum constant should be followed by only a trailing comma in the line.
finalize.implementation.missed.try.finally = finalize() method should contain try-finally block with super.finalize() call inside finally block.
finalize.implementation.public = finalize() method should have a "protected" visibility.
finalize.implementation.useless = finalize() method is useless: it does nothing except for calling super.finalize().
diff --git a/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/checks/coding/EnumTrailingCommaCheckTest.java b/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/checks/coding/EnumTrailingCommaCheckTest.java
new file mode 100644
index 0000000000..64ea45514e
--- /dev/null
+++ b/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/checks/coding/EnumTrailingCommaCheckTest.java
@@ -0,0 +1,56 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2018 the original author or authors.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+////////////////////////////////////////////////////////////////////////////////
+
+package com.github.sevntu.checkstyle.checks.coding;
+
+import static com.github.sevntu.checkstyle.checks.coding.EnumTrailingCommaCheck.MSG_KEY;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
+import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
+
+public class EnumTrailingCommaCheckTest extends AbstractModuleTestSupport {
+
+ @Override
+ protected String getPackageLocation() {
+ return "com/github/sevntu/checkstyle/checks/coding";
+ }
+
+ @Test
+ public void testDefault() throws Exception {
+ final DefaultConfiguration checkConfig =
+ createModuleConfig(EnumTrailingCommaCheck.class);
+ final String[] expected = {
+ "14:9: " + getCheckMessage(MSG_KEY),
+ "20:9: " + getCheckMessage(MSG_KEY),
+ "26:15: " + getCheckMessage(MSG_KEY),
+ };
+ verify(checkConfig, getPath("InputEnumTrailingCommaCheck.java"), expected);
+ }
+
+ @Test
+ public void testTokensNotNull() {
+ final EnumTrailingCommaCheck check = new EnumTrailingCommaCheck();
+ Assert.assertNotNull(check.getAcceptableTokens());
+ Assert.assertNotNull(check.getDefaultTokens());
+ Assert.assertNotNull(check.getRequiredTokens());
+ }
+}
diff --git a/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/internal/CheckstyleRegressionTest.java b/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/internal/CheckstyleRegressionTest.java
index f4d25eeef8..e053cdb7f1 100644
--- a/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/internal/CheckstyleRegressionTest.java
+++ b/sevntu-checks/src/test/java/com/github/sevntu/checkstyle/internal/CheckstyleRegressionTest.java
@@ -36,7 +36,12 @@ public class CheckstyleRegressionTest {
/** List of checks to suppress if we dynamically add it to the configuration. */
private static final List