001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2014  Oliver Burn
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.Check;
023import com.puppycrawl.tools.checkstyle.api.DetailAST;
024import com.puppycrawl.tools.checkstyle.api.Utils;
025import java.util.regex.Pattern;
026import java.util.regex.PatternSyntaxException;
027import org.apache.commons.beanutils.ConversionException;
028
029/**
030 * Checks for long lines.
031 *
032 * <p>
033 * Rationale: Long lines are hard to read in printouts or if developers
034 * have limited screen space for the source code, e.g. if the IDE displays
035 * additional information like project tree, class hierarchy, etc.
036 * </p>
037 *
038 * <p>
039 * Note: Support for the special handling of imports in CheckStyle Version 2
040 * has been dropped as it is a special case of regexp: The user can set
041 * the ignorePattern to "^import" and achieve the same effect.
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="^ *\* *[^ ]+$"/&gt;
072 * &lt;/module&gt;
073 * </pre>
074 *
075 * @author Lars Kühne
076 */
077public class LineLengthCheck extends Check
078{
079    /** default maximum number of columns in a line */
080    private static final int DEFAULT_MAX_COLUMNS = 80;
081
082    /** the maximum number of columns in a line */
083    private int max = DEFAULT_MAX_COLUMNS;
084
085    /** the regexp when long lines are ignored */
086    private Pattern ignorePattern;
087
088    /**
089     * Creates a new <code>LineLengthCheck</code> instance.
090     */
091    public LineLengthCheck()
092    {
093        setIgnorePattern("^$");
094    }
095
096    @Override
097    public int[] getDefaultTokens()
098    {
099        return new int[0];
100    }
101
102    @Override
103    public void beginTree(DetailAST rootAST)
104    {
105        final String[] lines = getLines();
106        for (int i = 0; i < lines.length; i++) {
107
108            final String line = lines[i];
109            final int realLength = Utils.lengthExpandedTabs(
110                line, line.length(), getTabWidth());
111
112
113            if ((realLength > max)
114                && !ignorePattern.matcher(line).find())
115            {
116                log(i + 1, "maxLineLen", max, realLength);
117            }
118        }
119    }
120
121    /**
122     * @param length the maximum length of a line
123     */
124    public void setMax(int length)
125    {
126        max = length;
127    }
128
129    /**
130     * Set the ignore pattern.
131     * @param format a <code>String</code> value
132     * @throws ConversionException unable to parse format
133     */
134    public void setIgnorePattern(String format)
135        throws ConversionException
136    {
137        try {
138            ignorePattern = Utils.getPattern(format);
139        }
140        catch (final PatternSyntaxException e) {
141            throw new ConversionException("unable to parse " + format, e);
142        }
143    }
144}