001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2024 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 in enum definitions.
030 * Semicolon is not needed if enum body contains only enum constants.
031 * </p>
032 * <p>
033 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
034 * </p>
035 * <p>
036 * Violation Message Keys:
037 * </p>
038 * <ul>
039 * <li>
040 * {@code unnecessary.semicolon}
041 * </li>
042 * </ul>
043 *
044 * @since 8.22
045 */
046@StatelessCheck
047public final class UnnecessarySemicolonInEnumerationCheck extends AbstractCheck {
048
049    /**
050     * A key is pointing to the warning message text in "messages.properties"
051     * file.
052     */
053    public static final String MSG_SEMI = "unnecessary.semicolon";
054
055    @Override
056    public int[] getDefaultTokens() {
057        return getRequiredTokens();
058    }
059
060    @Override
061    public int[] getAcceptableTokens() {
062        return getRequiredTokens();
063    }
064
065    @Override
066    public int[] getRequiredTokens() {
067        return new int[] {
068            TokenTypes.ENUM_DEF,
069        };
070    }
071
072    @Override
073    public void visitToken(DetailAST ast) {
074        final DetailAST enumBlock = ast.findFirstToken(TokenTypes.OBJBLOCK);
075        final DetailAST semicolon = enumBlock.findFirstToken(TokenTypes.SEMI);
076        if (semicolon != null && isEndOfEnumerationAfter(semicolon)) {
077            log(semicolon, MSG_SEMI);
078        }
079    }
080
081    /**
082     * Checks if enum body has no code elements after enum constants semicolon.
083     *
084     * @param ast semicolon in enum constants definition end
085     * @return true if there is no code elements, false otherwise.
086     */
087    private static boolean isEndOfEnumerationAfter(DetailAST ast) {
088        return ast.getNextSibling().getType() == TokenTypes.RCURLY;
089    }
090}