001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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.sizes;
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 * <p>
029 * Checks for long anonymous inner classes.
030 * </p>
031 * <p>
032 * Rationale: If an anonymous inner class becomes very long
033 * it is hard to understand and to see the flow of the method
034 * where the class is defined. Therefore long anonymous inner
035 * classes should usually be refactored into a named inner class.
036 * See also Bloch, Effective Java, p. 93.
037 * </p>
038 * <ul>
039 * <li>
040 * Property {@code max} - Specify the maximum number of lines allowed.
041 * Default value is {@code 20}.
042 * </li>
043 * </ul>
044 * <p>
045 * To configure the check to accept anonymous classes with up to 20 lines:
046 * </p>
047 * <pre>
048 * &lt;module name="AnonInnerLength"/&gt;
049 * </pre>
050 * <p>
051 * To configure the check to accept anonymous classes with up to 60 lines:
052 * </p>
053 * <pre>
054 * &lt;module name="AnonInnerLength"&gt;
055 *   &lt;property name="max" value="60"/&gt;
056 * &lt;/module&gt;
057 * </pre>
058 *
059 * @since 3.2
060 */
061@StatelessCheck
062public class AnonInnerLengthCheck 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 = "maxLen.anonInner";
069
070    /** Default maximum number of lines. */
071    private static final int DEFAULT_MAX = 20;
072
073    /** Specify the maximum number of lines allowed. */
074    private int max = DEFAULT_MAX;
075
076    @Override
077    public int[] getDefaultTokens() {
078        return getRequiredTokens();
079    }
080
081    @Override
082    public int[] getAcceptableTokens() {
083        return getRequiredTokens();
084    }
085
086    @Override
087    public int[] getRequiredTokens() {
088        return new int[] {TokenTypes.LITERAL_NEW};
089    }
090
091    @Override
092    public void visitToken(DetailAST ast) {
093        final DetailAST openingBrace = ast.findFirstToken(TokenTypes.OBJBLOCK);
094        if (openingBrace != null) {
095            final DetailAST closingBrace =
096                openingBrace.findFirstToken(TokenTypes.RCURLY);
097            final int length =
098                closingBrace.getLineNo() - openingBrace.getLineNo() + 1;
099            if (length > max) {
100                log(ast, MSG_KEY, length, max);
101            }
102        }
103    }
104
105    /**
106     * Setter to specify the maximum number of lines allowed.
107     *
108     * @param length the maximum length of an anonymous inner class.
109     */
110    public void setMax(int length) {
111        max = length;
112    }
113
114}