KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > gnu > regexp > RETokenOneOf


1 /*
2  * gnu/regexp/RETokenOneOf.java
3  * Copyright (C) 1998-2001 Wes Biggs
4  *
5  * This library is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU Lesser General Public License as published
7  * by the Free Software Foundation; either version 2.1 of the License, or
8  * (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
13  * GNU Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18  */
19
20 package gnu.regexp;
21 import java.util.Vector JavaDoc;
22
23 final class RETokenOneOf extends REToken {
24   private Vector JavaDoc options;
25   private boolean negative;
26
27   // This constructor is used for convenience when we know the set beforehand,
28 // e.g. \d --> new RETokenOneOf("0123456789",false, ..)
29 // \D --> new RETokenOneOf("0123456789",true, ..)
30
31   RETokenOneOf(int subIndex, String JavaDoc optionsStr, boolean negative, boolean insens) {
32     super(subIndex);
33     options = new Vector JavaDoc();
34     this.negative = negative;
35     for (int i = 0; i < optionsStr.length(); i++)
36       options.addElement(new RETokenChar(subIndex,optionsStr.charAt(i),insens));
37   }
38
39   RETokenOneOf(int subIndex, Vector JavaDoc options, boolean negative) {
40     super(subIndex);
41     this.options = options;
42     this.negative = negative;
43   }
44
45   int getMinimumLength() {
46     int min = Integer.MAX_VALUE;
47     int x;
48     for (int i=0; i < options.size(); i++) {
49       if ((x = ((REToken) options.elementAt(i)).getMinimumLength()) < min)
50     min = x;
51     }
52     return min;
53   }
54
55     boolean match(CharIndexed input, REMatch mymatch) {
56     if (negative && (input.charAt(mymatch.index) == CharIndexed.OUT_OF_BOUNDS))
57       return false;
58
59     REMatch newMatch = null;
60     REMatch last = null;
61     REToken tk;
62     boolean isMatch;
63     for (int i=0; i < options.size(); i++) {
64     tk = (REToken) options.elementAt(i);
65     REMatch tryMatch = (REMatch) mymatch.clone();
66     if (tk.match(input, tryMatch)) { // match was successful
67 if (negative) return false;
68
69         if (next(input, tryMatch)) {
70         // Add tryMatch to list of possibilities.
71 if (last == null) {
72             newMatch = tryMatch;
73             last = tryMatch;
74         } else {
75             last.next = tryMatch;
76             last = tryMatch;
77         }
78         } // next succeeds
79 } // is a match
80 } // try next option
81
82     if (newMatch != null) {
83     if (negative) {
84         return false;
85     } else {
86         // set contents of mymatch equal to newMatch
87
88         // try each one that matched
89 mymatch.assignFrom(newMatch);
90         return true;
91     }
92     } else {
93     if (negative) {
94         ++mymatch.index;
95         return next(input, mymatch);
96     } else {
97         return false;
98     }
99     }
100
101     // index+1 works for [^abc] lists, not for generic lookahead (--> index)
102 }
103
104   void dump(StringBuffer JavaDoc os) {
105     os.append(negative ? "[^" : "(?:");
106     for (int i = 0; i < options.size(); i++) {
107       if (!negative && (i > 0)) os.append('|');
108       ((REToken) options.elementAt(i)).dumpAll(os);
109     }
110     os.append(negative ? ']' : ')');
111   }
112 }
113
Popular Tags