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 * Type is {@code int}.
042 * Default value is {@code 20}.
043 * </li>
044 * </ul>
045 * <p>
046 * To configure the check to accept anonymous classes with up to 20 lines:
047 * </p>
048 * <pre>
049 * &lt;module name="AnonInnerLength"/&gt;
050 * </pre>
051 * <p>
052 * To configure the check to accept anonymous classes with up to 60 lines:
053 * </p>
054 * <pre>
055 * &lt;module name="AnonInnerLength"&gt;
056 *   &lt;property name="max" value="60"/&gt;
057 * &lt;/module&gt;
058 * </pre>
059 * <p>
060 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
061 * </p>
062 * <p>
063 * Violation Message Keys:
064 * </p>
065 * <ul>
066 * <li>
067 * {@code maxLen.anonInner}
068 * </li>
069 * </ul>
070 *
071 * @since 3.2
072 */
073@StatelessCheck
074public class AnonInnerLengthCheck extends AbstractCheck {
075
076    /**
077     * A key is pointing to the warning message text in "messages.properties"
078     * file.
079     */
080    public static final String MSG_KEY = "maxLen.anonInner";
081
082    /** Default maximum number of lines. */
083    private static final int DEFAULT_MAX = 20;
084
085    /** Specify the maximum number of lines allowed. */
086    private int max = DEFAULT_MAX;
087
088    @Override
089    public int[] getDefaultTokens() {
090        return getRequiredTokens();
091    }
092
093    @Override
094    public int[] getAcceptableTokens() {
095        return getRequiredTokens();
096    }
097
098    @Override
099    public int[] getRequiredTokens() {
100        return new int[] {TokenTypes.LITERAL_NEW};
101    }
102
103    @Override
104    public void visitToken(DetailAST ast) {
105        final DetailAST openingBrace = ast.findFirstToken(TokenTypes.OBJBLOCK);
106        if (openingBrace != null) {
107            final DetailAST closingBrace =
108                openingBrace.findFirstToken(TokenTypes.RCURLY);
109            final int length =
110                closingBrace.getLineNo() - openingBrace.getLineNo() + 1;
111            if (length > max) {
112                log(ast, MSG_KEY, length, max);
113            }
114        }
115    }
116
117    /**
118     * Setter to specify the maximum number of lines allowed.
119     *
120     * @param length the maximum length of an anonymous inner class.
121     */
122    public void setMax(int length) {
123        max = length;
124    }
125
126}