001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2019 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.naming;
021
022import java.util.regex.Pattern;
023
024import com.puppycrawl.tools.checkstyle.StatelessCheck;
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 * <p>
032 * Checks that package names conform to a format specified
033 * by the format property.
034 * </p>
035 * <p>
036 * The default value of {@code format} for module {@code PackageName} has been chosen to match
037 * the requirements in the
038 * <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.5.3">Java Language specification</a>
039 * and the Sun coding conventions. However both underscores and uppercase letters are rather
040 * uncommon, so most configurations should probably assign value
041 * {@code ^[a-z]+(\.[a-z][a-z0-9]*)*$} to {@code format} for module {@code PackageName}.
042 * </p>
043 * <ul>
044 * <li>
045 * Property {@code format} - Specifies valid identifiers. Default value is
046 * {@code "^[a-z]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$"}.
047 * </li>
048 * </ul>
049 * <p>
050 * An example of how to configure the check is:
051 * </p>
052 * <pre>
053 * &lt;module name="PackageName"/&gt;
054 * </pre>
055 * <p>
056 * An example of how to configure the check to ensure with packages start with a lowercase letter
057 * and only contains lowercase letters or numbers is:
058 * </p>
059 * <pre>
060 * &lt;module name=&quot;PackageName&quot;&gt;
061 *   &lt;property name=&quot;format&quot;
062 *     value=&quot;^[a-z]+(\.[a-z][a-z0-9]*)*$&quot;/&gt;
063 * &lt;/module&gt;
064 * </pre>
065 *
066 * @since 3.0
067 */
068@StatelessCheck
069public class PackageNameCheck
070    extends AbstractCheck {
071
072    /**
073     * A key is pointing to the warning message text in "messages.properties"
074     * file.
075     */
076    public static final String MSG_KEY = "name.invalidPattern";
077
078    /** Specifies valid identifiers. */
079    // Uppercase letters seem rather uncommon, but they're allowed in
080    // https://docs.oracle.com/javase/specs/
081    //  second_edition/html/packages.doc.html#40169
082    private Pattern format = Pattern.compile("^[a-z]+(\\.[a-zA-Z_][a-zA-Z0-9_]*)*$");
083
084    /**
085     * Setter to specifies valid identifiers.
086     * @param pattern the new pattern
087     */
088    public void setFormat(Pattern pattern) {
089        format = pattern;
090    }
091
092    @Override
093    public int[] getDefaultTokens() {
094        return getRequiredTokens();
095    }
096
097    @Override
098    public int[] getAcceptableTokens() {
099        return getRequiredTokens();
100    }
101
102    @Override
103    public int[] getRequiredTokens() {
104        return new int[] {TokenTypes.PACKAGE_DEF};
105    }
106
107    @Override
108    public void visitToken(DetailAST ast) {
109        final DetailAST nameAST = ast.getLastChild().getPreviousSibling();
110        final FullIdent full = FullIdent.createFullIdent(nameAST);
111        if (!format.matcher(full.getText()).find()) {
112            log(full.getDetailAst(),
113                MSG_KEY,
114                full.getText(),
115                format.pattern());
116        }
117    }
118
119}