001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2017 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.FileContents;
026import com.puppycrawl.tools.checkstyle.api.TokenTypes;
027import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
028
029/**
030 * <p>
031 * Checks for long methods.
032 * </p>
033 * <p>
034 * Rationale: If a method becomes very long it is hard to understand.
035 * Therefore long methods should usually be refactored into several
036 * individual methods that focus on a specific task.
037 * </p>
038 *<p>
039 * The default maximum method length is 150 lines. To change the maximum
040 * number of lines, set property max.
041 * </p>
042 * <p>
043 * An example of how to configure the check is:
044 * </p>
045 * <pre>
046 * &lt;module name="MethodLength"/&gt;
047 * </pre>
048 * <p>
049 * An example of how to configure the check so that it accepts methods with at
050 * most 60 lines is:
051 * </p>
052 * <pre>
053 * &lt;module name="MethodLength"&gt;
054 *    &lt;property name="max" value="60"/&gt;
055 * &lt;/module&gt;
056 * </pre>
057 * @author Lars K├╝hne
058 */
059@StatelessCheck
060public class MethodLengthCheck extends AbstractCheck {
061
062    /**
063     * A key is pointing to the warning message text in "messages.properties"
064     * file.
065     */
066    public static final String MSG_KEY = "maxLen.method";
067
068    /** Default maximum number of lines. */
069    private static final int DEFAULT_MAX_LINES = 150;
070
071    /** Whether to ignore empty lines and single line comments. */
072    private boolean countEmpty = true;
073
074    /** The maximum number of lines. */
075    private int max = DEFAULT_MAX_LINES;
076
077    @Override
078    public int[] getDefaultTokens() {
079        return getAcceptableTokens();
080    }
081
082    @Override
083    public int[] getAcceptableTokens() {
084        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
085    }
086
087    @Override
088    public int[] getRequiredTokens() {
089        return CommonUtils.EMPTY_INT_ARRAY;
090    }
091
092    @Override
093    public void visitToken(DetailAST ast) {
094        final DetailAST openingBrace = ast.findFirstToken(TokenTypes.SLIST);
095        if (openingBrace != null) {
096            final DetailAST closingBrace =
097                openingBrace.findFirstToken(TokenTypes.RCURLY);
098            final int length = getLengthOfBlock(openingBrace, closingBrace);
099            if (length > max) {
100                log(ast.getLineNo(), ast.getColumnNo(), MSG_KEY,
101                        length, max);
102            }
103        }
104    }
105
106    /**
107     * Returns length of code only without comments and blank lines.
108     * @param openingBrace block opening brace
109     * @param closingBrace block closing brace
110     * @return number of lines with code for current block
111     */
112    private int getLengthOfBlock(DetailAST openingBrace, DetailAST closingBrace) {
113        int length = closingBrace.getLineNo() - openingBrace.getLineNo() + 1;
114
115        if (!countEmpty) {
116            final FileContents contents = getFileContents();
117            final int lastLine = closingBrace.getLineNo();
118            // lastLine - 1 is actual last line index. Last line is line with curly brace,
119            // which is always not empty. So, we make it lastLine - 2 to cover last line that
120            // actually may be empty.
121            for (int i = openingBrace.getLineNo() - 1; i <= lastLine - 2; i++) {
122                if (contents.lineIsBlank(i) || contents.lineIsComment(i)) {
123                    length--;
124                }
125            }
126        }
127        return length;
128    }
129
130    /**
131     * Sets maximum length of a method.
132     * @param length the maximum length of a method.
133     */
134    public void setMax(int length) {
135        max = length;
136    }
137
138    /**
139     * Sets countEmpty.
140     * @param countEmpty whether to count empty and single line comments
141     *     of the form //.
142     */
143    public void setCountEmpty(boolean countEmpty) {
144        this.countEmpty = countEmpty;
145    }
146}