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1   ////////////////////////////////////////////////////////////////////////////////
2   // checkstyle: Checks Java source code for adherence to a set of rules.
3   // Copyright (C) 2001-2017 the original author or authors.
4   //
5   // This library is free software; you can redistribute it and/or
6   // modify it under the terms of the GNU Lesser General Public
7   // License as published by the Free Software Foundation; either
8   // version 2.1 of the License, or (at your option) any later version.
9   //
10  // This library is distributed in the hope that it will be useful,
11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  // Lesser General Public License for more details.
14  //
15  // You should have received a copy of the GNU Lesser General Public
16  // License along with this library; if not, write to the Free Software
17  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  ////////////////////////////////////////////////////////////////////////////////
19  
20  package com.puppycrawl.tools.checkstyle.checks.whitespace;
21  
22  import java.util.Locale;
23  
24  import com.puppycrawl.tools.checkstyle.StatelessCheck;
25  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
26  import com.puppycrawl.tools.checkstyle.api.DetailAST;
27  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
28  import com.puppycrawl.tools.checkstyle.utils.CommonUtils;
29  
30  /**
31   * <p>Checks the padding of an empty for initializer; that is whether a
32   * space is required at an empty for initializer, or such spaces are
33   * forbidden. No check occurs if there is a line wrap at the initializer, as in
34   * </p>
35   * <pre class="body">
36  for (
37        ; i &lt; j; i++, j--)
38     </pre>
39   * <p>
40   * The policy to verify is specified using the {@link PadOption} class and
41   * defaults to {@link PadOption#NOSPACE}.
42   * </p>
43   * <p>
44   * An example of how to configure the check is:
45   * </p>
46   * <pre>
47   * &lt;module name="EmptyForInitializerPad"/&gt;
48   * </pre>
49   *
50   * @author lkuehne
51   */
52  @StatelessCheck
53  public class EmptyForInitializerPadCheck
54      extends AbstractCheck {
55  
56      /**
57       * A key is pointing to the warning message text in "messages.properties"
58       * file.
59       */
60      public static final String MSG_PRECEDED = "ws.preceded";
61  
62      /**
63       * A key is pointing to the warning message text in "messages.properties"
64       * file.
65       */
66      public static final String MSG_NOT_PRECEDED = "ws.notPreceded";
67  
68      /** Semicolon literal. */
69      private static final String SEMICOLON = ";";
70  
71      /** The policy to enforce. */
72      private PadOption option = PadOption.NOSPACE;
73  
74      /**
75       * Set the option to enforce.
76       * @param optionStr string to decode option from
77       * @throws IllegalArgumentException if unable to decode
78       */
79      public void setOption(String optionStr) {
80          try {
81              option = PadOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
82          }
83          catch (IllegalArgumentException iae) {
84              throw new IllegalArgumentException("unable to parse " + optionStr, iae);
85          }
86      }
87  
88      @Override
89      public int[] getDefaultTokens() {
90          return getRequiredTokens();
91      }
92  
93      @Override
94      public int[] getAcceptableTokens() {
95          return getRequiredTokens();
96      }
97  
98      @Override
99      public int[] getRequiredTokens() {
100         return new int[] {TokenTypes.FOR_INIT};
101     }
102 
103     @Override
104     public void visitToken(DetailAST ast) {
105         if (ast.getChildCount() == 0) {
106             //empty for initializer. test pad before semi.
107             final DetailAST semi = ast.getNextSibling();
108             final int semiLineIdx = semi.getLineNo() - 1;
109             final String line = getLines()[semiLineIdx];
110             final int before = semi.getColumnNo() - 1;
111             //don't check if semi at beginning of line
112             if (!CommonUtils.hasWhitespaceBefore(before, line)) {
113                 if (option == PadOption.NOSPACE
114                     && Character.isWhitespace(line.charAt(before))) {
115                     log(semi.getLineNo(), before, MSG_PRECEDED, SEMICOLON);
116                 }
117                 else if (option == PadOption.SPACE
118                          && !Character.isWhitespace(line.charAt(before))) {
119                     log(semi.getLineNo(), before, MSG_NOT_PRECEDED, SEMICOLON);
120                 }
121             }
122         }
123     }
124 }