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 java.io.File;
023
024import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
025import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
026import com.puppycrawl.tools.checkstyle.api.DetailAST;
027import com.puppycrawl.tools.checkstyle.api.FullIdent;
028import com.puppycrawl.tools.checkstyle.api.TokenTypes;
029
030/**
031 * <div>
032 * Ensures that a class has a package declaration, and (optionally) whether
033 * the package name matches the directory name for the source file.
034 * </div>
035 *
036 * <p>
037 * Rationale: Classes that live in the null package cannot be imported.
038 * Many novice developers are not aware of this.
039 * </p>
040 *
041 * <p>
042 * Packages provide logical namespace to classes and should be stored in
043 * the form of directory levels to provide physical grouping to your classes.
044 * These directories are added to the classpath so that your classes
045 * are visible to JVM when it runs the code.
046 * </p>
047 * <ul>
048 * <li>
049 * Property {@code matchDirectoryStructure} - Control whether to check for
050 * directory and package name match.
051 * Type is {@code boolean}.
052 * Default value is {@code true}.
053 * </li>
054 * </ul>
055 *
056 * <p>
057 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
058 * </p>
059 *
060 * <p>
061 * Violation Message Keys:
062 * </p>
063 * <ul>
064 * <li>
065 * {@code mismatch.package.directory}
066 * </li>
067 * <li>
068 * {@code missing.package.declaration}
069 * </li>
070 * </ul>
071 *
072 * @since 3.2
073 */
074@FileStatefulCheck
075public final class PackageDeclarationCheck extends AbstractCheck {
076
077    /**
078     * A key is pointing to the warning message text in "messages.properties"
079     * file.
080     */
081    public static final String MSG_KEY_MISSING = "missing.package.declaration";
082
083    /**
084     * A key is pointing to the warning message text in "messages.properties"
085     * file.
086     */
087    public static final String MSG_KEY_MISMATCH = "mismatch.package.directory";
088
089    /** Is package defined. */
090    private boolean defined;
091
092    /** Control whether to check for directory and package name match. */
093    private boolean matchDirectoryStructure = true;
094
095    /**
096     * Setter to control whether to check for directory and package name match.
097     *
098     * @param matchDirectoryStructure the new value.
099     * @since 7.6.1
100     */
101    public void setMatchDirectoryStructure(boolean matchDirectoryStructure) {
102        this.matchDirectoryStructure = matchDirectoryStructure;
103    }
104
105    @Override
106    public int[] getDefaultTokens() {
107        return getRequiredTokens();
108    }
109
110    @Override
111    public int[] getRequiredTokens() {
112        return new int[] {TokenTypes.PACKAGE_DEF};
113    }
114
115    @Override
116    public int[] getAcceptableTokens() {
117        return getRequiredTokens();
118    }
119
120    @Override
121    public void beginTree(DetailAST ast) {
122        defined = false;
123    }
124
125    @Override
126    public void finishTree(DetailAST ast) {
127        if (!defined && ast != null) {
128            log(ast, MSG_KEY_MISSING);
129        }
130    }
131
132    @Override
133    public void visitToken(DetailAST ast) {
134        defined = true;
135
136        if (matchDirectoryStructure) {
137            final DetailAST packageNameAst = ast.getLastChild().getPreviousSibling();
138            final FullIdent fullIdent = FullIdent.createFullIdent(packageNameAst);
139            final String packageName = fullIdent.getText().replace('.', File.separatorChar);
140
141            final String directoryName = getDirectoryName();
142
143            if (!directoryName.endsWith(packageName)) {
144                log(ast, MSG_KEY_MISMATCH, packageName);
145            }
146        }
147    }
148
149    /**
150     * Returns the directory name this file is in.
151     *
152     * @return Directory name.
153     */
154    private String getDirectoryName() {
155        final String fileName = getFilePath();
156        final int lastSeparatorPos = fileName.lastIndexOf(File.separatorChar);
157        return fileName.substring(0, lastSeparatorPos);
158    }
159
160}