001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2015 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 java.util.regex.Pattern;
023
024import org.apache.commons.lang3.ArrayUtils;
025
026import com.puppycrawl.tools.checkstyle.api.Check;
027import com.puppycrawl.tools.checkstyle.api.DetailAST;
028import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
029
030/**
031 * Checks for long lines.
032 *
033 * <p>
034 * Rationale: Long lines are hard to read in printouts or if developers
035 * have limited screen space for the source code, e.g. if the IDE displays
036 * additional information like project tree, class hierarchy, etc.
037 * </p>
038 *
039 * <p>
040 * Package statements and import statements (lines matching pattern
041 * {@code ^(package|import) .*}), and are not verified by this check.
042 * </p>
043 * <p>
044 * The default maximum allowable line length is 80 characters. To change the
045 * maximum, set property max.
046 * </p>
047 * <p>
048 * To ignore lines in the check, set property ignorePattern to a regular
049 * expression for the lines to ignore.
050 * </p>
051 * <p>
052 * An example of how to configure the check is:
053 * </p>
054 * <pre>
055 * &lt;module name="LineLength"/&gt;
056 * </pre>
057 * <p> An example of how to configure the check to accept lines up to 120
058 * characters long is:
059 *</p>
060 * <pre>
061 * &lt;module name="LineLength"&gt;
062 *    &lt;property name="max" value="120"/&gt;
063 * &lt;/module&gt;
064 * </pre>
065 * <p> An example of how to configure the check to ignore lines that begin with
066 * &quot; * &quot;, followed by just one word, such as within a Javadoc comment,
067 * is:
068 * </p>
069 * <pre>
070 * &lt;module name="LineLength"&gt;
071 *    &lt;property name="ignorePattern" value="^ *\* *[^ ]+$"/&gt;
072 * &lt;/module&gt;
073 * </pre>
074 *
075 * @author Lars Kühne
076 */
077public class LineLengthCheck extends Check {
078
079    /**
080     * A key is pointing to the warning message text in "messages.properties"
081     * file.
082     */
083    public static final String MSG_KEY = "maxLineLen";
084
085    /** Default maximum number of columns in a line. */
086    private static final int DEFAULT_MAX_COLUMNS = 80;
087
088    /** Patterns matching package, import, and import static statements. */
089    private static final Pattern IGNORE_PATTERN = Pattern.compile("^(package|import) .*");
090
091    /** The maximum number of columns in a line. */
092    private int max = DEFAULT_MAX_COLUMNS;
093
094    /** The regexp when long lines are ignored. */
095    private Pattern ignorePattern;
096
097    /**
098     * Creates a new {@code LineLengthCheck} instance.
099     */
100    public LineLengthCheck() {
101        setIgnorePattern("^$");
102    }
103
104    @Override
105    public int[] getDefaultTokens() {
106        return ArrayUtils.EMPTY_INT_ARRAY;
107    }
108
109    @Override
110    public int[] getAcceptableTokens() {
111        return ArrayUtils.EMPTY_INT_ARRAY;
112    }
113
114    @Override
115    public int[] getRequiredTokens() {
116        return ArrayUtils.EMPTY_INT_ARRAY;
117    }
118
119    @Override
120    public void beginTree(DetailAST rootAST) {
121        final String[] lines = getLines();
122        for (int i = 0; i < lines.length; i++) {
123
124            final String line = lines[i];
125            final int realLength = CommonUtils.lengthExpandedTabs(
126                line, line.length(), getTabWidth());
127
128            if (realLength > max && !IGNORE_PATTERN.matcher(line).find()
129                && !ignorePattern.matcher(line).find()) {
130                log(i + 1, MSG_KEY, max, realLength);
131            }
132        }
133    }
134
135    /**
136     * Sets the maximum length of a line.
137     * @param length the maximum length of a line
138     */
139    public void setMax(int length) {
140        max = length;
141    }
142
143    /**
144     * Set the ignore pattern.
145     * @param format a {@code String} value
146     */
147    public final void setIgnorePattern(String format) {
148        ignorePattern = CommonUtils.createPattern(format);
149    }
150}