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.utils.CommonUtil; 026 027/** 028 * <div> 029 * Checks whether file contains code. 030 * Java compiler is not raising errors on files with no code or all commented out. 031 * Files which are considered to have no code: 032 * </div> 033 * 034 * <ul> 035 * <li> 036 * File with no text 037 * </li> 038 * <li> 039 * File with single-line comment(s) 040 * </li> 041 * <li> 042 * File with a multi line comment(s). 043 * </li> 044 * </ul> 045 * 046 * <p> 047 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker} 048 * </p> 049 * 050 * <p> 051 * Violation Message Keys: 052 * </p> 053 * <ul> 054 * <li> 055 * {@code nocode.in.file} 056 * </li> 057 * </ul> 058 * 059 * @since 8.33 060 */ 061@StatelessCheck 062public class NoCodeInFileCheck extends AbstractCheck { 063 064 /** 065 * A key is pointing to the warning message text in "messages.properties" 066 * file. 067 */ 068 public static final String MSG_KEY_NO_CODE = "nocode.in.file"; 069 070 /** Line number used to log violation when no AST nodes are present in file. */ 071 private static final int DEFAULT_LINE_NUMBER = 1; 072 073 @Override 074 public int[] getDefaultTokens() { 075 return getRequiredTokens(); 076 } 077 078 @Override 079 public int[] getAcceptableTokens() { 080 return getRequiredTokens(); 081 } 082 083 @Override 084 public int[] getRequiredTokens() { 085 return CommonUtil.EMPTY_INT_ARRAY; 086 } 087 088 @Override 089 public void finishTree(DetailAST ast) { 090 if (ast == null) { 091 log(DEFAULT_LINE_NUMBER, MSG_KEY_NO_CODE); 092 } 093 } 094}