001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2019 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.coding;
021
022import com.puppycrawl.tools.checkstyle.StatelessCheck;
023import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
024import com.puppycrawl.tools.checkstyle.api.DetailAST;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026
027/**
028 * <p>
029 * Checks if unnecessary semicolon is used in last resource declaration.
030 * </p>
031 * <ul>
032 * <li>
033 * Property {@code allowWhenNoBraceAfterSemicolon} -
034 * Allow unnecessary semicolon if closing paren is not on the same line.
035 * Default value is {@code true}.
036 * </li>
037 * </ul>
038 * <p>
039 * To configure the check:
040 * </p>
041 * <pre>
042 * &lt;module name=&quot;UnnecessarySemicolonInTryWithResources&quot;/&gt;
043 * </pre>
044 * <p>
045 * Example of violations
046 * </p>
047 * <pre>
048 * class A {
049 *     void method() throws IOException {
050 *         try(Reader r1 = new PipedReader();){} // violation
051 *         try(Reader r4 = new PipedReader();Reader r5 = new PipedReader()
052 *         ;){} // violation
053 *         try(Reader r6 = new PipedReader();
054 *             Reader r7
055 *                    = new PipedReader();
056 *         ){}
057 *     }
058 * }
059 * </pre>
060 * <p>
061 * To configure the check to detect unnecessary semicolon
062 * if closing paren is not on same line
063 * </p>
064 * <pre>
065 * &lt;module name="UnnecessarySemicolonInTryWithResources"&gt;
066 *   &lt;property name="allowWhenNoBraceAfterSemicolon" value="false"/&gt;
067 * &lt;/module&gt;
068 * </pre>
069 * <p>
070 * Example of exclusion
071 * </p>
072 * <pre>
073 * class A {
074 *     void method() throws IOException {
075 *         try(Reader r1 = new PipedReader();){} // violation
076 *         try(Reader r6 = new PipedReader();
077 *             Reader r7 = new PipedReader(); // violation
078 *         ){}
079 *     }
080 * }
081 * </pre>
082 *
083 * @since 8.22
084 */
085@StatelessCheck
086public final class UnnecessarySemicolonInTryWithResourcesCheck extends AbstractCheck {
087
088    /**
089     * A key is pointing to the warning message text in "messages.properties"
090     * file.
091     */
092    public static final String MSG_SEMI = "unnecessary.semicolon";
093
094    /** Allow unnecessary semicolon if closing paren is not on the same line. */
095    private boolean allowWhenNoBraceAfterSemicolon = true;
096
097    @Override
098    public int[] getDefaultTokens() {
099        return getRequiredTokens();
100    }
101
102    @Override
103    public int[] getAcceptableTokens() {
104        return getRequiredTokens();
105    }
106
107    @Override
108    public int[] getRequiredTokens() {
109        return new int[] {
110            TokenTypes.RESOURCE_SPECIFICATION,
111        };
112    }
113
114    /**
115     * Setter to allow unnecessary semicolon if closing paren is not on the same line.
116     * @param allowWhenNoBraceAfterSemicolon a value to set.
117     */
118    public void setAllowWhenNoBraceAfterSemicolon(boolean allowWhenNoBraceAfterSemicolon) {
119        this.allowWhenNoBraceAfterSemicolon = allowWhenNoBraceAfterSemicolon;
120    }
121
122    @Override
123    public void visitToken(DetailAST ast) {
124        final DetailAST closingParen = ast.getLastChild();
125        final DetailAST tokenBeforeCloseParen = closingParen.getPreviousSibling();
126        if (tokenBeforeCloseParen.getType() == TokenTypes.SEMI
127            && (!allowWhenNoBraceAfterSemicolon
128                || closingParen.getLineNo() == tokenBeforeCloseParen.getLineNo())) {
129            log(tokenBeforeCloseParen, MSG_SEMI);
130        }
131    }
132
133}