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1   /*
2    *
3    * Copyright 2004 The Ant-Contrib project
4    *
5    *  Licensed under the Apache License, Version 2.0 (the "License");
6    *  you may not use this file except in compliance with the License.
7    *  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   */
17  package org.codehaus.mojo.natives.parser;
18  
19  /**
20   * This parser state checks consumed characters against a specific character (case insensitive).
21   * 
22   * @author Curt Arnold
23   */
24  public final class CaseInsensitiveLetterState
25      extends AbstractParserState
26  {
27      /**
28       * Next state if a match is found.
29       */
30      private final AbstractParserState nextState;
31  
32      /**
33       * Next state if not match is found.
34       */
35      private final AbstractParserState noMatchState;
36  
37      /**
38       * Lower case version of character to match.
39       */
40      private final char lowerLetter;
41  
42      /**
43       * Lower case version of character to match.
44       */
45      private final char upperLetter;
46  
47      /**
48       * Constructor.
49       * 
50       * @param parser parser
51       * @param matchLetter letter to match
52       * @param nextStateArg next state if a match on the letter
53       * @param noMatchStateArg state if no match on letter
54       */
55      public CaseInsensitiveLetterState( final AbstractParser parser, final char matchLetter,
56                                         final AbstractParserState nextStateArg, final AbstractParserState noMatchStateArg )
57      {
58          super( parser );
59          this.lowerLetter = Character.toLowerCase( matchLetter );
60          this.upperLetter = Character.toUpperCase( matchLetter );
61          this.nextState = nextStateArg;
62          this.noMatchState = noMatchStateArg;
63      }
64  
65      /**
66       * Consumes a character and returns the next state for the parser.
67       * 
68       * @param ch next character
69       * @return the configured nextState if ch is the expected character or the configure noMatchState otherwise.
70       */
71      public AbstractParserState consume( final char ch )
72      {
73          if ( ch == lowerLetter || ch == upperLetter )
74          {
75              return nextState;
76          }
77          if ( ch == '\n' )
78          {
79              getParser().getNewLineState();
80          }
81          return noMatchState;
82      }
83  }