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17 package org.apache.commons.jexl.parser;
18
19 /***
20 * Describes the input token stream.
21 */
22
23 public class Token {
24
25 /***
26 * An integer that describes the kind of this token. This numbering system
27 * is determined by JavaCCParser, and a table of these numbers is stored in
28 * the file ...Constants.java.
29 */
30 public int kind;
31
32 /***
33 * beginLine and beginColumn describe the position of the first character of
34 * this token; endLine and endColumn describe the position of the last
35 * character of this token.
36 */
37 public int beginLine, beginColumn, endLine, endColumn;
38
39 /***
40 * The string image of the token.
41 */
42 public String image;
43
44 /***
45 * A reference to the next regular (non-special) token from the input
46 * stream. If this is the last token from the input stream, or if the token
47 * manager has not read tokens beyond this one, this field is set to null.
48 * This is true only if this token is also a regular token. Otherwise, see
49 * below for a description of the contents of this field.
50 */
51 public Token next;
52
53 /***
54 * This field is used to access special tokens that occur prior to this
55 * token, but after the immediately preceding regular (non-special) token.
56 * If there are no such special tokens, this field is set to null. When
57 * there are more than one such special token, this field refers to the last
58 * of these special tokens, which in turn refers to the next previous
59 * special token through its specialToken field, and so on until the first
60 * special token (whose specialToken field is null). The next fields of
61 * special tokens refer to other special tokens that immediately follow it
62 * (without an intervening regular token). If there is no such token, this
63 * field is null.
64 */
65 public Token specialToken;
66
67 /***
68 * Returns the image.
69 */
70 public final String toString() {
71 return image;
72 }
73
74 /***
75 * Returns a new Token object, by default. However, if you want, you can
76 * create and return subclass objects based on the value of ofKind. Simply
77 * add the cases to the switch for all those special cases. For example, if
78 * you have a subclass of Token called IDToken that you want to create if
79 * ofKind is ID, simlpy add something like :
80 *
81 * case MyParserConstants.ID : return new IDToken();
82 *
83 * to the following switch statement. Then you can cast matchedToken
84 * variable to the appropriate type and use it in your lexical actions.
85 */
86 public static final Token newToken(int ofKind) {
87 switch (ofKind) {
88 default:
89 return new Token();
90 }
91 }
92
93 }