001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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;
026import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
027
028/**
029 * <p>
030 * Checks if unnecessary semicolon is used in last resource declaration.
031 * </p>
032 * <ul>
033 * <li>
034 * Property {@code allowWhenNoBraceAfterSemicolon} -
035 * Allow unnecessary semicolon if closing paren is not on the same line.
036 * Default value is {@code true}.
037 * </li>
038 * </ul>
039 * <p>
040 * To configure the check:
041 * </p>
042 * <pre>
043 * &lt;module name=&quot;UnnecessarySemicolonInTryWithResources&quot;/&gt;
044 * </pre>
045 * <p>
046 * Example of violations
047 * </p>
048 * <pre>
049 * class A {
050 *     void method() throws IOException {
051 *         try(Reader r1 = new PipedReader();){} // violation
052 *         try(Reader r4 = new PipedReader();Reader r5 = new PipedReader()
053 *         ;){} // violation
054 *         try(Reader r6 = new PipedReader();
055 *             Reader r7
056 *                    = new PipedReader();
057 *         ){}
058 *     }
059 * }
060 * </pre>
061 * <p>
062 * To configure the check to detect unnecessary semicolon
063 * if closing paren is not on same line
064 * </p>
065 * <pre>
066 * &lt;module name="UnnecessarySemicolonInTryWithResources"&gt;
067 *   &lt;property name="allowWhenNoBraceAfterSemicolon" value="false"/&gt;
068 * &lt;/module&gt;
069 * </pre>
070 * <p>
071 * Example of exclusion
072 * </p>
073 * <pre>
074 * class A {
075 *     void method() throws IOException {
076 *         try(Reader r1 = new PipedReader();){} // violation
077 *         try(Reader r6 = new PipedReader();
078 *             Reader r7 = new PipedReader(); // violation
079 *         ){}
080 *     }
081 * }
082 * </pre>
083 *
084 * @since 8.22
085 */
086@StatelessCheck
087public final class UnnecessarySemicolonInTryWithResourcesCheck extends AbstractCheck {
088
089    /**
090     * A key is pointing to the warning message text in "messages.properties"
091     * file.
092     */
093    public static final String MSG_SEMI = "unnecessary.semicolon";
094
095    /** Allow unnecessary semicolon if closing paren is not on the same line. */
096    private boolean allowWhenNoBraceAfterSemicolon = true;
097
098    @Override
099    public int[] getDefaultTokens() {
100        return getRequiredTokens();
101    }
102
103    @Override
104    public int[] getAcceptableTokens() {
105        return getRequiredTokens();
106    }
107
108    @Override
109    public int[] getRequiredTokens() {
110        return new int[] {
111            TokenTypes.RESOURCE_SPECIFICATION,
112        };
113    }
114
115    /**
116     * Setter to allow unnecessary semicolon if closing paren is not on the same line.
117     *
118     * @param allowWhenNoBraceAfterSemicolon a value to set.
119     */
120    public void setAllowWhenNoBraceAfterSemicolon(boolean allowWhenNoBraceAfterSemicolon) {
121        this.allowWhenNoBraceAfterSemicolon = allowWhenNoBraceAfterSemicolon;
122    }
123
124    @Override
125    public void visitToken(DetailAST ast) {
126        final DetailAST closingParen = ast.getLastChild();
127        final DetailAST tokenBeforeCloseParen = closingParen.getPreviousSibling();
128        if (tokenBeforeCloseParen.getType() == TokenTypes.SEMI
129            && (!allowWhenNoBraceAfterSemicolon
130                || TokenUtil.areOnSameLine(closingParen, tokenBeforeCloseParen))) {
131            log(tokenBeforeCloseParen, MSG_SEMI);
132        }
133    }
134
135}