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; 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 * <div> 029 * Checks that long constants are defined with an upper ell. That is {@code 'L'} 030 * and not {@code 'l'}. This is in accordance with the Java Language Specification, 031 * <a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-3.html#jls-3.10.1"> 032 * Section 3.10.1</a>. 033 * </div> 034 * 035 * <p> 036 * Rationale: The lower-case ell {@code 'l'} looks a lot like {@code 1}. 037 * </p> 038 * 039 * <p> 040 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 041 * </p> 042 * 043 * <p> 044 * Violation Message Keys: 045 * </p> 046 * <ul> 047 * <li> 048 * {@code upperEll} 049 * </li> 050 * </ul> 051 * 052 * @since 3.0 053 */ 054@StatelessCheck 055public class UpperEllCheck extends AbstractCheck { 056 057 /** 058 * A key is pointing to the warning message text in "messages.properties" 059 * file. 060 */ 061 public static final String MSG_KEY = "upperEll"; 062 063 @Override 064 public int[] getDefaultTokens() { 065 return getRequiredTokens(); 066 } 067 068 @Override 069 public int[] getAcceptableTokens() { 070 return getRequiredTokens(); 071 } 072 073 @Override 074 public int[] getRequiredTokens() { 075 return new int[] {TokenTypes.NUM_LONG}; 076 } 077 078 @Override 079 public void visitToken(DetailAST ast) { 080 if (ast.getText().endsWith("l")) { 081 log(ast, MSG_KEY); 082 } 083 } 084 085}