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 * <div> 029 * Checks that array initialization do not contain a trailing comma. 030 * Rationale: JLS allows trailing commas in arrays and enumerations, but does not allow 031 * them in other locations. To unify the coding style, the use of trailing commas should 032 * be prohibited. 033 * </div> 034 * <pre> 035 * int[] foo = new int[] { 036 * 1, 037 * 2 038 * }; 039 * </pre> 040 * 041 * <p> 042 * The check demands that there should not be any comma after the last element of an array. 043 * </p> 044 * <pre> 045 * String[] foo = new String[] { 046 * "FOO", 047 * "BAR", //violation 048 * } 049 * </pre> 050 * 051 * <p> 052 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 053 * </p> 054 * 055 * <p> 056 * Violation Message Keys: 057 * </p> 058 * <ul> 059 * <li> 060 * {@code no.array.trailing.comma} 061 * </li> 062 * </ul> 063 * 064 * @since 8.28 065 */ 066@StatelessCheck 067public class NoArrayTrailingCommaCheck extends AbstractCheck { 068 069 /** 070 * A key is pointing to the warning message text in "messages.properties" 071 * file. 072 */ 073 public static final String MSG_KEY = "no.array.trailing.comma"; 074 075 @Override 076 public int[] getDefaultTokens() { 077 return getRequiredTokens(); 078 } 079 080 @Override 081 public int[] getAcceptableTokens() { 082 return getRequiredTokens(); 083 } 084 085 @Override 086 public int[] getRequiredTokens() { 087 return new int[] {TokenTypes.ARRAY_INIT}; 088 } 089 090 @Override 091 public void visitToken(DetailAST arrayInit) { 092 final DetailAST rcurly = arrayInit.findFirstToken(TokenTypes.RCURLY); 093 final DetailAST previousSibling = rcurly.getPreviousSibling(); 094 if (previousSibling != null && previousSibling.getType() == TokenTypes.COMMA) { 095 log(previousSibling, MSG_KEY); 096 } 097 } 098}