001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2017 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.CommonUtils;
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 * @author Oliver Burn
050 */
051@StatelessCheck
052public class UpperEllCheck extends AbstractCheck {
053
054    /**
055     * A key is pointing to the warning message text in "messages.properties"
056     * file.
057     */
058    public static final String MSG_KEY = "upperEll";
059
060    @Override
061    public int[] getDefaultTokens() {
062        return getRequiredTokens();
063    }
064
065    @Override
066    public int[] getAcceptableTokens() {
067        return getRequiredTokens();
068    }
069
070    @Override
071    public int[] getRequiredTokens() {
072        return new int[] {TokenTypes.NUM_LONG};
073    }
074
075    @Override
076    public void visitToken(DetailAST ast) {
077        if (CommonUtils.endsWithChar(ast.getText(), 'l')) {
078            log(ast.getLineNo(),
079                ast.getColumnNo() + ast.getText().length() - 1,
080                MSG_KEY);
081        }
082    }
083}