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1   ///////////////////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
3   // Copyright (C) 2001-2025 the original author or authors.
4   //
5   // This library is free software; you can redistribute it and/or
6   // modify it under the terms of the GNU Lesser General Public
7   // License as published by the Free Software Foundation; either
8   // version 2.1 of the License, or (at your option) any later version.
9   //
10  // This library is distributed in the hope that it will be useful,
11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  // Lesser General Public License for more details.
14  //
15  // You should have received a copy of the GNU Lesser General Public
16  // License along with this library; if not, write to the Free Software
17  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  ///////////////////////////////////////////////////////////////////////////////////////////////
19  
20  package com.puppycrawl.tools.checkstyle.checks.coding;
21  
22  import java.io.File;
23  
24  import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
25  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
26  import com.puppycrawl.tools.checkstyle.api.DetailAST;
27  import com.puppycrawl.tools.checkstyle.api.FullIdent;
28  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
29  
30  /**
31   * <div>
32   * Ensures that a class has a package declaration, and (optionally) whether
33   * the package name matches the directory name for the source file.
34   * </div>
35   *
36   * <p>
37   * Rationale: Classes that live in the null package cannot be imported.
38   * Many novice developers are not aware of this.
39   * </p>
40   *
41   * <p>
42   * Packages provide logical namespace to classes and should be stored in
43   * the form of directory levels to provide physical grouping to your classes.
44   * These directories are added to the classpath so that your classes
45   * are visible to JVM when it runs the code.
46   * </p>
47   *
48   * @since 3.2
49   */
50  @FileStatefulCheck
51  public final class PackageDeclarationCheck extends AbstractCheck {
52  
53      /**
54       * A key is pointing to the warning message text in "messages.properties"
55       * file.
56       */
57      public static final String MSG_KEY_MISSING = "missing.package.declaration";
58  
59      /**
60       * A key is pointing to the warning message text in "messages.properties"
61       * file.
62       */
63      public static final String MSG_KEY_MISMATCH = "mismatch.package.directory";
64  
65      /** Is package defined. */
66      private boolean defined;
67  
68      /** Control whether to check for directory and package name match. */
69      private boolean matchDirectoryStructure = true;
70  
71      /**
72       * Setter to control whether to check for directory and package name match.
73       *
74       * @param matchDirectoryStructure the new value.
75       * @since 7.6.1
76       */
77      public void setMatchDirectoryStructure(boolean matchDirectoryStructure) {
78          this.matchDirectoryStructure = matchDirectoryStructure;
79      }
80  
81      @Override
82      public int[] getDefaultTokens() {
83          return getRequiredTokens();
84      }
85  
86      @Override
87      public int[] getRequiredTokens() {
88          return new int[] {TokenTypes.PACKAGE_DEF};
89      }
90  
91      @Override
92      public int[] getAcceptableTokens() {
93          return getRequiredTokens();
94      }
95  
96      @Override
97      public void beginTree(DetailAST ast) {
98          defined = false;
99      }
100 
101     @Override
102     public void finishTree(DetailAST ast) {
103         if (!defined && ast != null) {
104             log(ast, MSG_KEY_MISSING);
105         }
106     }
107 
108     @Override
109     public void visitToken(DetailAST ast) {
110         defined = true;
111 
112         if (matchDirectoryStructure) {
113             final DetailAST packageNameAst = ast.getLastChild().getPreviousSibling();
114             final FullIdent fullIdent = FullIdent.createFullIdent(packageNameAst);
115             final String packageName = fullIdent.getText().replace('.', File.separatorChar);
116 
117             final String directoryName = getDirectoryName();
118 
119             if (!directoryName.endsWith(packageName)) {
120                 log(ast, MSG_KEY_MISMATCH, packageName);
121             }
122         }
123     }
124 
125     /**
126      * Returns the directory name this file is in.
127      *
128      * @return Directory name.
129      */
130     private String getDirectoryName() {
131         final String fileName = getFilePath();
132         final int lastSeparatorPos = fileName.lastIndexOf(File.separatorChar);
133         return fileName.substring(0, lastSeparatorPos);
134     }
135 
136 }