001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2020 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.whitespace;
021
022import java.util.Locale;
023
024import com.puppycrawl.tools.checkstyle.StatelessCheck;
025import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
026import com.puppycrawl.tools.checkstyle.api.DetailAST;
027import com.puppycrawl.tools.checkstyle.api.TokenTypes;
028import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
029
030/**
031 * <p>
032 * Checks the padding of an empty for initializer; that is whether a white
033 * space is required at an empty for initializer, or such white space is
034 * forbidden.  No check occurs if there is a line wrap at the initializer, as in
035 * </p>
036 * <pre>
037 * for (
038 *     ; i &lt; j; i++, j--)
039 *  </pre>
040 * <ul>
041 * <li>
042 * Property {@code option} - Specify policy on how to pad an empty for iterator.
043 * Type is {@code com.puppycrawl.tools.checkstyle.checks.whitespace.PadOption}.
044 * Default value is {@code nospace}.
045 * </li>
046 * </ul>
047 * <p>
048 * To configure the check:
049 * </p>
050 * <pre>
051 * &lt;module name=&quot;EmptyForInitializerPad&quot;/&gt;
052 * </pre>
053 * <p>
054 * To configure the check to require white space at an empty for iterator:
055 * </p>
056 * <pre>
057 * &lt;module name=&quot;EmptyForInitializerPad&quot;&gt;
058 *   &lt;property name=&quot;option&quot; value=&quot;space&quot;/&gt;
059 * &lt;/module&gt;
060 * </pre>
061 * <p>
062 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
063 * </p>
064 * <p>
065 * Violation Message Keys:
066 * </p>
067 * <ul>
068 * <li>
069 * {@code ws.notPreceded}
070 * </li>
071 * <li>
072 * {@code ws.preceded}
073 * </li>
074 * </ul>
075 *
076 * @since 3.4
077 */
078@StatelessCheck
079public class EmptyForInitializerPadCheck
080    extends AbstractCheck {
081
082    /**
083     * A key is pointing to the warning message text in "messages.properties"
084     * file.
085     */
086    public static final String MSG_PRECEDED = "ws.preceded";
087
088    /**
089     * A key is pointing to the warning message text in "messages.properties"
090     * file.
091     */
092    public static final String MSG_NOT_PRECEDED = "ws.notPreceded";
093
094    /** Semicolon literal. */
095    private static final String SEMICOLON = ";";
096
097    /** Specify policy on how to pad an empty for iterator. */
098    private PadOption option = PadOption.NOSPACE;
099
100    /**
101     * Setter to specify policy on how to pad an empty for iterator.
102     *
103     * @param optionStr string to decode option from
104     * @throws IllegalArgumentException if unable to decode
105     */
106    public void setOption(String optionStr) {
107        option = PadOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
108    }
109
110    @Override
111    public int[] getDefaultTokens() {
112        return getRequiredTokens();
113    }
114
115    @Override
116    public int[] getAcceptableTokens() {
117        return getRequiredTokens();
118    }
119
120    @Override
121    public int[] getRequiredTokens() {
122        return new int[] {TokenTypes.FOR_INIT};
123    }
124
125    @Override
126    public void visitToken(DetailAST ast) {
127        if (!ast.hasChildren()) {
128            // empty for initializer. test pad before semi.
129            final DetailAST semi = ast.getNextSibling();
130            final int semiLineIdx = semi.getLineNo() - 1;
131            final String line = getLines()[semiLineIdx];
132            final int before = semi.getColumnNo() - 1;
133            // don't check if semi at beginning of line
134            if (!CommonUtil.hasWhitespaceBefore(before, line)) {
135                if (option == PadOption.NOSPACE
136                    && Character.isWhitespace(line.charAt(before))) {
137                    log(ast, MSG_PRECEDED, SEMICOLON);
138                }
139                else if (option == PadOption.SPACE
140                         && !Character.isWhitespace(line.charAt(before))) {
141                    log(ast, MSG_NOT_PRECEDED, SEMICOLON);
142                }
143            }
144        }
145    }
146
147}