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;
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.CommonUtil;
027
028/**
029 * <p>Checks that long constants are defined with an upper ell.
030 * That is <span class="code">'L'</span> and not
031 * <span class="code">'l'</span>. This is in accordance to the Java Language
032 * Specification, <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10.1">
033 * Section 3.10.1</a>.
034 * </p>
035 * <p>
036 * Rationale: The letter <span class="code">l</span> looks a lot
037 * like the number <span class="code">1</span>.
038 * </p>
039 *
040 * <p>Examples
041 * <p class="body">
042 * To configure the check:
043 *
044 * </p>
045 * <pre class="body">
046 * &lt;module name=&quot;UpperEll&quot;/&gt;
047 * </pre>
048 *
049 */
050@StatelessCheck
051public class UpperEllCheck extends AbstractCheck {
052
053    /**
054     * A key is pointing to the warning message text in "messages.properties"
055     * file.
056     */
057    public static final String MSG_KEY = "upperEll";
058
059    @Override
060    public int[] getDefaultTokens() {
061        return getRequiredTokens();
062    }
063
064    @Override
065    public int[] getAcceptableTokens() {
066        return getRequiredTokens();
067    }
068
069    @Override
070    public int[] getRequiredTokens() {
071        return new int[] {TokenTypes.NUM_LONG};
072    }
073
074    @Override
075    public void visitToken(DetailAST ast) {
076        if (CommonUtil.endsWithChar(ast.getText(), 'l')) {
077            log(ast, MSG_KEY);
078        }
079    }
080
081}