Issue #6774: Add UnnecessarySemicolonInTryWithResourcesCheck

.ci/jsoref-spellchecker/whitelist.words

@@ -1280,6 +1280,7 @@ Unitless
 unlzma
 unnecessaryparentheses
 unnecessarysemicoloninenumeration
+unnecessarysemicolonintrywithresources
 Unproxyable
 unregister
 unsubscribe

config/checkstyle_checks.xml

@@ -340,6 +340,7 @@
     <module name="SuperFinalize"/>
     <module name="UnnecessaryParentheses"/>
     <module name="UnnecessarySemicolonInEnumeration"/>
+    <module name="UnnecessarySemicolonInTryWithResources"/>
     <module name="VariableDeclarationUsageDistance"/>
 
     <!-- Filters-->

src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java

@@ -539,6 +539,8 @@ private static void fillChecksFromCodingPackage() {
                 BASE_PACKAGE + ".checks.coding.UnnecessaryParenthesesCheck");
         NAME_TO_FULL_MODULE_NAME.put("UnnecessarySemicolonInEnumerationCheck",
                 BASE_PACKAGE + ".checks.coding.UnnecessarySemicolonInEnumerationCheck");
+        NAME_TO_FULL_MODULE_NAME.put("UnnecessarySemicolonInTryWithResourcesCheck",
+                BASE_PACKAGE + ".checks.coding.UnnecessarySemicolonInTryWithResourcesCheck");
         NAME_TO_FULL_MODULE_NAME.put("VariableDeclarationUsageDistanceCheck",
                 BASE_PACKAGE + ".checks.coding.VariableDeclarationUsageDistanceCheck");
     }

src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInTryWithResourcesCheck.java

@@ -0,0 +1,133 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2019 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.puppycrawl.tools.checkstyle.checks.coding;
+
+import com.puppycrawl.tools.checkstyle.StatelessCheck;
+import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
+import com.puppycrawl.tools.checkstyle.api.DetailAST;
+import com.puppycrawl.tools.checkstyle.api.TokenTypes;
+
+/**
+ * <p>
+ * Checks if unnecessary semicolon is used in last resource declaration.
+ * </p>
+ * <ul>
+ * <li>
+ * Property {@code allowWhenNoBraceAfterSemicolon} -
+ * Allow unnecessary semicolon if closing paren is not on the same line.
+ * Default value is {@code true}.
+ * </li>
+ * </ul>
+ * <p>
+ * To configure the check:
+ * </p>
+ * <pre>
+ * &lt;module name=&quot;UnnecessarySemicolonInTryWithResources&quot;/&gt;
+ * </pre>
+ * <p>
+ * Example of violations
+ * </p>
+ * <pre>
+ * class A {
+ *     void method() throws IOException {
+ *         try(Reader r1 = new PipedReader();){} // violation
+ *         try(Reader r4 = new PipedReader();Reader r5 = new PipedReader()
+ *         ;){} // violation
+ *         try(Reader r6 = new PipedReader();
+ *             Reader r7
+ *                    = new PipedReader();
+ *         ){}
+ *     }
+ * }
+ * </pre>
+ * <p>
+ * To configure the check to detect unnecessary semicolon
+ * if closing paren is not on same line
+ * </p>
+ * <pre>
+ * &lt;module name="UnnecessarySemicolonInTryWithResources"&gt;
+ *   &lt;property name="allowWhenNoBraceAfterSemicolon" value="false"/&gt;
+ * &lt;/module&gt;
+ * </pre>
+ * <p>
+ * Example of exclusion
+ * </p>
+ * <pre>
+ * class A {
+ *     void method() throws IOException {
+ *         try(Reader r1 = new PipedReader();){} // violation
+ *         try(Reader r6 = new PipedReader();
+ *             Reader r7 = new PipedReader(); // violation
+ *         ){}
+ *     }
+ * }
+ * </pre>
+ *
+ * @since 8.22
+ */
+@StatelessCheck
+public final class UnnecessarySemicolonInTryWithResourcesCheck extends AbstractCheck {
+
+    /**
+     * A key is pointing to the warning message text in "messages.properties"
+     * file.
+     */
+    public static final String MSG_SEMI = "unnecessary.semicolon";
+
+    /** Allow unnecessary semicolon if closing paren is not on the same line. */
+    private boolean allowWhenNoBraceAfterSemicolon = true;
+
+    @Override
+    public int[] getDefaultTokens() {
+        return getRequiredTokens();
+    }
+
+    @Override
+    public int[] getAcceptableTokens() {
+        return getRequiredTokens();
+    }
+
+    @Override
+    public int[] getRequiredTokens() {
+        return new int[] {
+            TokenTypes.RESOURCE_SPECIFICATION,
+        };
+    }
+
+    /**
+     * Setter to allow unnecessary semicolon if closing paren is not on the same line.
+     * @param allowWhenNoBraceAfterSemicolon a value to set.
+     */
+    public void setAllowWhenNoBraceAfterSemicolon(boolean allowWhenNoBraceAfterSemicolon) {
+        this.allowWhenNoBraceAfterSemicolon = allowWhenNoBraceAfterSemicolon;
+    }
+
+    @Override
+    public void visitToken(DetailAST ast) {
+        final DetailAST closingParen = ast.getLastChild();
+        final DetailAST tokenBeforeCloseParen = closingParen.getPreviousSibling();
+        if (tokenBeforeCloseParen.getType() == TokenTypes.SEMI
+            && (!allowWhenNoBraceAfterSemicolon
+                || closingParen.getLineNo() == tokenBeforeCloseParen.getLineNo())) {
+            log(tokenBeforeCloseParen, MSG_SEMI);
+        }
+    }
+
+}

src/test/java/com/puppycrawl/tools/checkstyle/checks/coding/UnnecessarySemicolonInTryWithResourcesCheckTest.java

@@ -0,0 +1,83 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2019 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.puppycrawl.tools.checkstyle.checks.coding;
+
+import static com.puppycrawl.tools.checkstyle.checks.coding.UnnecessarySemicolonInTryWithResourcesCheck.MSG_SEMI;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
+import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
+import com.puppycrawl.tools.checkstyle.api.TokenTypes;
+
+public class UnnecessarySemicolonInTryWithResourcesCheckTest extends AbstractModuleTestSupport {
+
+    @Override
+    protected String getPackageLocation() {
+        return "com/puppycrawl/tools/checkstyle/checks/coding/"
+            + "unnecessarysemicolonintrywithresources";
+    }
+
+    @Test
+    public void testDefault() throws Exception {
+        final DefaultConfiguration checkConfig =
+            createModuleConfig(UnnecessarySemicolonInTryWithResourcesCheck.class);
+
+        final String[] expected = {
+            "13:42: " + getCheckMessage(MSG_SEMI),
+            "14:72: " + getCheckMessage(MSG_SEMI),
+        };
+
+        verify(checkConfig, getPath("InputUnnecessarySemicolonInTryWithResourcesDefault.java"),
+            expected);
+    }
+
+    @Test
+    public void testNoBraceAfterAllowed() throws Exception {
+        final DefaultConfiguration checkConfig =
+            createModuleConfig(UnnecessarySemicolonInTryWithResourcesCheck.class);
+        checkConfig.addAttribute("allowWhenNoBraceAfterSemicolon", "false");
+        final String[] expected = {
+            "13:42: " + getCheckMessage(MSG_SEMI),
+            "16:13: " + getCheckMessage(MSG_SEMI),
+            "19:36: " + getCheckMessage(MSG_SEMI),
+        };
+
+        verify(checkConfig,
+            getPath("InputUnnecessarySemicolonInTryWithResourcesNoBraceAfterAllowed.java"),
+            expected);
+    }
+
+    @Test
+    public void testTokensAreCorrect() {
+        final UnnecessarySemicolonInTryWithResourcesCheck check =
+            new UnnecessarySemicolonInTryWithResourcesCheck();
+        final int[] expected = {
+            TokenTypes.RESOURCE_SPECIFICATION,
+        };
+        Assert.assertArrayEquals("Acceptable required tokens are invalid",
+            expected, check.getAcceptableTokens());
+        Assert.assertArrayEquals("Default required tokens are invalid",
+            expected, check.getDefaultTokens());
+        Assert.assertArrayEquals("Required required tokens are invalid",
+            expected, check.getRequiredTokens());
+    }
+}

src/test/resources/com/puppycrawl/tools/checkstyle/checks/coding/unnecessarysemicolonintrywithresources/InputUnnecessarySemicolonInTryWithResourcesDefault.java

@@ -0,0 +1,25 @@
+package com.puppycrawl.tools.checkstyle.checks.coding.unnecessarysemicolonintrywithresources;
+
+import java.io.IOException;
+import java.io.PipedReader;
+import java.io.Reader;
+
+/**
+ * Default config
+ */
+public class InputUnnecessarySemicolonInTryWithResourcesDefault {
+
+    void method() throws IOException {
+        try(Reader r1 = new PipedReader();){} // violation
+        try(Reader r1 = new PipedReader();Reader r2 = new PipedReader();){} // violation
+        try(Reader r2 = new PipedReader();Reader r3 = new PipedReader()){}
+        try(Reader r4 = new PipedReader();
+            Reader r5 = new PipedReader();
+            ){}
+        try(Reader r6 = new PipedReader();
+            Reader r7
+                = new PipedReader();
+            ){}
+
+    }
+}

src/test/resources/com/puppycrawl/tools/checkstyle/checks/coding/unnecessarysemicolonintrywithresources/InputUnnecessarySemicolonInTryWithResourcesNoBraceAfterAllowed.java

@@ -0,0 +1,23 @@
+package com.puppycrawl.tools.checkstyle.checks.coding.unnecessarysemicolonintrywithresources;
+
+import java.io.IOException;
+import java.io.PipedReader;
+import java.io.Reader;
+
+/**
+ * "allowWhenNoBraceAfterSemicolon" = false
+ */
+public class InputUnnecessarySemicolonInTryWithResourcesNoBraceAfterAllowed {
+
+    void method() throws IOException {
+        try(Reader r1 = new PipedReader();){} // violation
+        try(Reader r2 = new PipedReader();Reader r3 = new PipedReader()){}
+        try(Reader r4 = new PipedReader();Reader r5 = new PipedReader()
+            ;){} // violation
+        try(Reader r6 = new PipedReader();
+            Reader r7
+                = new PipedReader(); // violation
+            ){}
+
+    }
+}

src/xdocs/checks.xml

@@ -814,6 +814,10 @@
         <td><a href="config_coding.html#UnnecessarySemicolonInEnumeration">UnnecessarySemicolonInEnumeration</a></td>
         <td>Checks if unnecessary semicolon is in enum definitions.</td>
       </tr>
+      <tr>
+        <td><a href="config_coding.html#UnnecessarySemicolonInTryWithResources">UnnecessarySemicolonInTryWithResources</a></td>
+        <td>Checks if unnecessary semicolon is used in last resource declaration.</td>
+      </tr>
       <tr>
         <td><a href="config_imports.html#UnusedImports">UnusedImports</a></td>
         <td>