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.api.AbstractCheck;
023import com.puppycrawl.tools.checkstyle.api.DetailAST;
024import com.puppycrawl.tools.checkstyle.api.FileContents;
025import com.puppycrawl.tools.checkstyle.api.TokenTypes;
026import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
027
028/**
029 * <p>
030 * Checks for long methods.
031 * </p>
032 * <p>
033 * Rationale: If a method becomes very long it is hard to understand.
034 * Therefore long methods should usually be refactored into several
035 * individual methods that focus on a specific task.
036 * </p>
037 *<p>
038 * The default maximum method length is 150 lines. To change the maximum
039 * number of lines, set property max.
040 * </p>
041 * <p>
042 * An example of how to configure the check is:
043 * </p>
044 * <pre>
045 * &lt;module name="MethodLength"/&gt;
046 * </pre>
047 * <p>
048 * An example of how to configure the check so that it accepts methods with at
049 * most 60 lines is:
050 * </p>
051 * <pre>
052 * &lt;module name="MethodLength"&gt;
053 *    &lt;property name="max" value="60"/&gt;
054 * &lt;/module&gt;
055 * </pre>
056 * @author Lars Kühne
057 */
058public class MethodLengthCheck extends AbstractCheck {
059
060    /**
061     * A key is pointing to the warning message text in "messages.properties"
062     * file.
063     */
064    public static final String MSG_KEY = "maxLen.method";
065
066    /** Default maximum number of lines. */
067    private static final int DEFAULT_MAX_LINES = 150;
068
069    /** Whether to ignore empty lines and single line comments. */
070    private boolean countEmpty = true;
071
072    /** The maximum number of lines. */
073    private int max = DEFAULT_MAX_LINES;
074
075    @Override
076    public int[] getDefaultTokens() {
077        return getAcceptableTokens();
078    }
079
080    @Override
081    public int[] getAcceptableTokens() {
082        return new int[] {TokenTypes.METHOD_DEF, TokenTypes.CTOR_DEF};
083    }
084
085    @Override
086    public int[] getRequiredTokens() {
087        return CommonUtils.EMPTY_INT_ARRAY;
088    }
089
090    @Override
091    public void visitToken(DetailAST ast) {
092        final DetailAST openingBrace = ast.findFirstToken(TokenTypes.SLIST);
093        if (openingBrace != null) {
094            final DetailAST closingBrace =
095                openingBrace.findFirstToken(TokenTypes.RCURLY);
096            final int length = getLengthOfBlock(openingBrace, closingBrace);
097            if (length > max) {
098                log(ast.getLineNo(), ast.getColumnNo(), MSG_KEY,
099                        length, max);
100            }
101        }
102    }
103
104    /**
105     * Returns length of code only without comments and blank lines.
106     * @param openingBrace block opening brace
107     * @param closingBrace block closing brace
108     * @return number of lines with code for current block
109     */
110    private int getLengthOfBlock(DetailAST openingBrace, DetailAST closingBrace) {
111        int length = closingBrace.getLineNo() - openingBrace.getLineNo() + 1;
112
113        if (!countEmpty) {
114            final FileContents contents = getFileContents();
115            final int lastLine = closingBrace.getLineNo();
116            for (int i = openingBrace.getLineNo() - 1; i < lastLine; i++) {
117                if (contents.lineIsBlank(i) || contents.lineIsComment(i)) {
118                    length--;
119                }
120            }
121        }
122        return length;
123    }
124
125    /**
126     * Sets maximum length of a method.
127     * @param length the maximum length of a method.
128     */
129    public void setMax(int length) {
130        max = length;
131    }
132
133    /**
134     * Sets countEmpty.
135     * @param countEmpty whether to count empty and single line comments
136     *     of the form //.
137     */
138    public void setCountEmpty(boolean countEmpty) {
139        this.countEmpty = countEmpty;
140    }
141}