001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2018 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 */
058@StatelessCheck
059public class MethodLengthCheck extends AbstractCheck {
060
061    /**
062     * A key is pointing to the warning message text in "messages.properties"
063     * file.
064     */
065    public static final String MSG_KEY = "maxLen.method";
066
067    /** Default maximum number of lines. */
068    private static final int DEFAULT_MAX_LINES = 150;
069
070    /** Whether to ignore empty lines and single line comments. */
071    private boolean countEmpty = true;
072
073    /** The maximum number of lines. */
074    private int max = DEFAULT_MAX_LINES;
075
076    @Override
077    public int[] getDefaultTokens() {
078        return getAcceptableTokens();
079    }
080
081    @Override
082    public int[] getAcceptableTokens() {
083        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
084    }
085
086    @Override
087    public int[] getRequiredTokens() {
088        return CommonUtils.EMPTY_INT_ARRAY;
089    }
090
091    @Override
092    public void visitToken(DetailAST ast) {
093        final DetailAST openingBrace = ast.findFirstToken(TokenTypes.SLIST);
094        if (openingBrace != null) {
095            final DetailAST closingBrace =
096                openingBrace.findFirstToken(TokenTypes.RCURLY);
097            final int length = getLengthOfBlock(openingBrace, closingBrace);
098            if (length > max) {
099                log(ast.getLineNo(), ast.getColumnNo(), MSG_KEY,
100                        length, max);
101            }
102        }
103    }
104
105    /**
106     * Returns length of code only without comments and blank lines.
107     * @param openingBrace block opening brace
108     * @param closingBrace block closing brace
109     * @return number of lines with code for current block
110     */
111    private int getLengthOfBlock(DetailAST openingBrace, DetailAST closingBrace) {
112        int length = closingBrace.getLineNo() - openingBrace.getLineNo() + 1;
113
114        if (!countEmpty) {
115            final FileContents contents = getFileContents();
116            final int lastLine = closingBrace.getLineNo();
117            // lastLine - 1 is actual last line index. Last line is line with curly brace,
118            // which is always not empty. So, we make it lastLine - 2 to cover last line that
119            // actually may be empty.
120            for (int i = openingBrace.getLineNo() - 1; i <= lastLine - 2; i++) {
121                if (contents.lineIsBlank(i) || contents.lineIsComment(i)) {
122                    length--;
123                }
124            }
125        }
126        return length;
127    }
128
129    /**
130     * Sets maximum length of a method.
131     * @param length the maximum length of a method.
132     */
133    public void setMax(int length) {
134        max = length;
135    }
136
137    /**
138     * Sets countEmpty.
139     * @param countEmpty whether to count empty and single line comments
140     *     of the form //.
141     */
142    public void setCountEmpty(boolean countEmpty) {
143        this.countEmpty = countEmpty;
144    }
145
146}