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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>
32   * Checks the padding between the identifier of a method definition,
33   * constructor definition, method call, or constructor invocation;
34   * and the left parenthesis of the parameter list.
35   * That is, if the identifier and left parenthesis are on the same line,
36   * checks whether a space is required immediately after the identifier or
37   * such a space is forbidden.
38   * If they are not on the same line, reports an error, unless configured to
39   * allow line breaks.
40   * </p>
41   * <p> By default the check will check the following tokens:
42   *  {@link TokenTypes#CTOR_DEF CTOR_DEF},
43   *  {@link TokenTypes#LITERAL_NEW LITERAL_NEW},
44   *  {@link TokenTypes#METHOD_CALL METHOD_CALL},
45   *  {@link TokenTypes#METHOD_DEF METHOD_DEF},
46   *  {@link TokenTypes#SUPER_CTOR_CALL SUPER_CTOR_CALL}.
47   * </p>
48   * <p>
49   * An example of how to configure the check is:
50   * </p>
51   * <pre>
52   * &lt;module name="MethodParamPad"/&gt;
53   * </pre>
54   * <p> An example of how to configure the check to require a space
55   * after the identifier of a method definition, except if the left
56   * parenthesis occurs on a new line, is:
57   * </p>
58   * <pre>
59   * &lt;module name="MethodParamPad"&gt;
60   *     &lt;property name="tokens" value="METHOD_DEF"/&gt;
61   *     &lt;property name="option" value="space"/&gt;
62   *     &lt;property name="allowLineBreaks" value="true"/&gt;
63   * &lt;/module&gt;
64   * </pre>
65   * @author Rick Giles
66   */
67  
68  @StatelessCheck
69  public class MethodParamPadCheck
70      extends AbstractCheck {
71  
72      /**
73       * A key is pointing to the warning message text in "messages.properties"
74       * file.
75       */
76      public static final String MSG_LINE_PREVIOUS = "line.previous";
77  
78      /**
79       * A key is pointing to the warning message text in "messages.properties"
80       * file.
81       */
82      public static final String MSG_WS_PRECEDED = "ws.preceded";
83  
84      /**
85       * A key is pointing to the warning message text in "messages.properties"
86       * file.
87       */
88      public static final String MSG_WS_NOT_PRECEDED = "ws.notPreceded";
89  
90      /**
91       * Whether whitespace is allowed if the method identifier is at a
92       * linebreak.
93       */
94      private boolean allowLineBreaks;
95  
96      /** The policy to enforce. */
97      private PadOption option = PadOption.NOSPACE;
98  
99      @Override
100     public int[] getDefaultTokens() {
101         return getAcceptableTokens();
102     }
103 
104     @Override
105     public int[] getAcceptableTokens() {
106         return new int[] {
107             TokenTypes.CTOR_DEF,
108             TokenTypes.LITERAL_NEW,
109             TokenTypes.METHOD_CALL,
110             TokenTypes.METHOD_DEF,
111             TokenTypes.SUPER_CTOR_CALL,
112             TokenTypes.ENUM_CONSTANT_DEF,
113         };
114     }
115 
116     @Override
117     public int[] getRequiredTokens() {
118         return CommonUtils.EMPTY_INT_ARRAY;
119     }
120 
121     @Override
122     public void visitToken(DetailAST ast) {
123         final DetailAST parenAST;
124         if (ast.getType() == TokenTypes.METHOD_CALL) {
125             parenAST = ast;
126         }
127         else {
128             parenAST = ast.findFirstToken(TokenTypes.LPAREN);
129             // array construction => parenAST == null
130         }
131 
132         if (parenAST != null) {
133             final String line = getLines()[parenAST.getLineNo() - 1];
134             if (CommonUtils.hasWhitespaceBefore(parenAST.getColumnNo(), line)) {
135                 if (!allowLineBreaks) {
136                     log(parenAST, MSG_LINE_PREVIOUS, parenAST.getText());
137                 }
138             }
139             else {
140                 final int before = parenAST.getColumnNo() - 1;
141                 if (option == PadOption.NOSPACE
142                     && Character.isWhitespace(line.charAt(before))) {
143                     log(parenAST, MSG_WS_PRECEDED, parenAST.getText());
144                 }
145                 else if (option == PadOption.SPACE
146                          && !Character.isWhitespace(line.charAt(before))) {
147                     log(parenAST, MSG_WS_NOT_PRECEDED, parenAST.getText());
148                 }
149             }
150         }
151     }
152 
153     /**
154      * Control whether whitespace is flagged at line breaks.
155      * @param allowLineBreaks whether whitespace should be
156      *     flagged at line breaks.
157      */
158     public void setAllowLineBreaks(boolean allowLineBreaks) {
159         this.allowLineBreaks = allowLineBreaks;
160     }
161 
162     /**
163      * Set the option to enforce.
164      * @param optionStr string to decode option from
165      * @throws IllegalArgumentException if unable to decode
166      */
167     public void setOption(String optionStr) {
168         try {
169             option = PadOption.valueOf(optionStr.trim().toUpperCase(Locale.ENGLISH));
170         }
171         catch (IllegalArgumentException iae) {
172             throw new IllegalArgumentException("unable to parse " + optionStr, iae);
173         }
174     }
175 }