001////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code for adherence to a set of rules.
003// Copyright (C) 2001-2022 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;
028
029/**
030 * <p>
031 * Checks the padding of an empty for iterator; that is whether a white
032 * space is required at an empty for iterator, or such white space is
033 * forbidden. No check occurs if there is a line wrap at the iterator, as in
034 * </p>
035 * <pre>
036 * for (Iterator foo = very.long.line.iterator();
037 *     foo.hasNext();
038 *    )
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;EmptyForIteratorPad&quot;/&gt;
052 * </pre>
053 * <p>
054 * Example:
055 * </p>
056 * <pre>
057 * for (Iterator it = map.entrySet().iterator();  it.hasNext(););  // ok
058 * for (Iterator it = map.entrySet().iterator();  it.hasNext(); ); // violation since whitespace
059 *                                                                 //after semicolon
060 *
061 * for (Iterator foo = very.long.line.iterator();
062 *       foo.hasNext();
063 *      ); // ok
064 * </pre>
065 * <p>
066 * To configure the check to require white space at an empty for iterator:
067 * </p>
068 * <pre>
069 * &lt;module name=&quot;EmptyForIteratorPad&quot;&gt;
070 *   &lt;property name=&quot;option&quot; value=&quot;space&quot;/&gt;
071 * &lt;/module&gt;
072 * </pre>
073 * <p>
074 * Example:
075 * </p>
076 * <pre>
077 * for (Iterator it = map.entrySet().iterator();  it.hasNext();); // violation as there is no
078 *                                                                // whitespace after semicolon
079 *
080 * for (Iterator it = map.entrySet().iterator();  it.hasNext(); ); // ok
081 *
082 * for (Iterator foo = very.long.line.iterator();
083 *       foo.hasNext();
084 *      ); // violation as there  is no whitespace after semicolon
085 * </pre>
086 * <p>
087 * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
088 * </p>
089 * <p>
090 * Violation Message Keys:
091 * </p>
092 * <ul>
093 * <li>
094 * {@code ws.followed}
095 * </li>
096 * <li>
097 * {@code ws.notFollowed}
098 * </li>
099 * </ul>
100 *
101 * @since 3.0
102 */
103@StatelessCheck
104public class EmptyForIteratorPadCheck
105    extends AbstractCheck {
106
107    /**
108     * A key is pointing to the warning message text in "messages.properties"
109     * file.
110     */
111    public static final String MSG_WS_FOLLOWED = "ws.followed";
112
113    /**
114     * A key is pointing to the warning message text in "messages.properties"
115     * file.
116     */
117    public static final String MSG_WS_NOT_FOLLOWED = "ws.notFollowed";
118
119    /** Semicolon literal. */
120    private static final String SEMICOLON = ";";
121
122    /** Specify policy on how to pad an empty for iterator. */
123    private PadOption option = PadOption.NOSPACE;
124
125    /**
126     * Setter to specify policy on how to pad an empty for iterator.
127     *
128     * @param optionStr string to decode option from
129     * @throws IllegalArgumentException if unable to decode
130     */
131    public void setOption(String optionStr) {
132        option = PadOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
133    }
134
135    @Override
136    public int[] getDefaultTokens() {
137        return getRequiredTokens();
138    }
139
140    @Override
141    public int[] getAcceptableTokens() {
142        return getRequiredTokens();
143    }
144
145    @Override
146    public int[] getRequiredTokens() {
147        return new int[] {TokenTypes.FOR_ITERATOR};
148    }
149
150    @Override
151    public void visitToken(DetailAST ast) {
152        if (!ast.hasChildren()) {
153            // empty for iterator. test pad after semi.
154            final DetailAST semi = ast.getPreviousSibling();
155            final String line = getLines()[semi.getLineNo() - 1];
156            final int after = semi.getColumnNo() + 1;
157            // don't check if at end of line
158            if (after < line.length()) {
159                if (option == PadOption.NOSPACE
160                    && Character.isWhitespace(line.charAt(after))) {
161                    log(ast, MSG_WS_FOLLOWED, SEMICOLON);
162                }
163                else if (option == PadOption.SPACE
164                         && !Character.isWhitespace(line.charAt(after))) {
165                    log(ast, MSG_WS_NOT_FOLLOWED, SEMICOLON);
166                }
167            }
168        }
169    }
170
171}