2
|
1 |
/*
|
5506
|
2 |
* Copyright (c) 1995, 2001, Oracle and/or its affiliates. All rights reserved.
|
2
|
3 |
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
4 |
*
|
|
5 |
* This code is free software; you can redistribute it and/or modify it
|
|
6 |
* under the terms of the GNU General Public License version 2 only, as
|
5506
|
7 |
* published by the Free Software Foundation. Oracle designates this
|
2
|
8 |
* particular file as subject to the "Classpath" exception as provided
|
5506
|
9 |
* by Oracle in the LICENSE file that accompanied this code.
|
2
|
10 |
*
|
|
11 |
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
12 |
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
13 |
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
14 |
* version 2 for more details (a copy is included in the LICENSE file that
|
|
15 |
* accompanied this code).
|
|
16 |
*
|
|
17 |
* You should have received a copy of the GNU General Public License version
|
|
18 |
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
19 |
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
20 |
*
|
5506
|
21 |
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
22 |
* or visit www.oracle.com if you need additional information or have any
|
|
23 |
* questions.
|
2
|
24 |
*/
|
|
25 |
|
|
26 |
package sun.misc;
|
|
27 |
import java.io.*;
|
|
28 |
|
|
29 |
/**
|
|
30 |
* A class to represent a pool of regular expressions. A string
|
|
31 |
* can be matched against the whole pool all at once. It is much
|
|
32 |
* faster than doing individual regular expression matches one-by-one.
|
|
33 |
*
|
|
34 |
* @see java.misc.RegexpTarget
|
|
35 |
* @author James Gosling
|
|
36 |
*/
|
|
37 |
|
|
38 |
public class RegexpPool {
|
|
39 |
private RegexpNode prefixMachine = new RegexpNode();
|
|
40 |
private RegexpNode suffixMachine = new RegexpNode();
|
|
41 |
private static final int BIG = 0x7FFFFFFF;
|
|
42 |
private int lastDepth = BIG;
|
|
43 |
|
|
44 |
public RegexpPool () {
|
|
45 |
}
|
|
46 |
|
|
47 |
/**
|
|
48 |
* Add a regular expression to the pool of regular expressions.
|
|
49 |
* @param re The regular expression to add to the pool.
|
|
50 |
For now, only handles strings that either begin or end with
|
|
51 |
a '*'.
|
|
52 |
* @param ret The object to be returned when this regular expression is
|
|
53 |
matched. If ret is an instance of the RegexpTarget class, ret.found
|
|
54 |
is called with the string fragment that matched the '*' as its
|
|
55 |
parameter.
|
|
56 |
* @exception REException error
|
|
57 |
*/
|
|
58 |
public void add(String re, Object ret) throws REException {
|
|
59 |
add(re, ret, false);
|
|
60 |
}
|
|
61 |
|
|
62 |
/**
|
|
63 |
* Replace the target for the regular expression with a different
|
|
64 |
* target.
|
|
65 |
*
|
|
66 |
* @param re The regular expression to be replaced in the pool.
|
|
67 |
* For now, only handles strings that either begin or end with
|
|
68 |
* a '*'.
|
|
69 |
* @param ret The object to be returned when this regular expression is
|
|
70 |
* matched. If ret is an instance of the RegexpTarget class, ret.found
|
|
71 |
* is called with the string fragment that matched the '*' as its
|
|
72 |
* parameter.
|
|
73 |
*/
|
|
74 |
public void replace(String re, Object ret) {
|
|
75 |
try {
|
|
76 |
add(re, ret, true);
|
|
77 |
} catch(Exception e) {
|
|
78 |
// should never occur if replace is true
|
|
79 |
}
|
|
80 |
}
|
|
81 |
|
|
82 |
/**
|
|
83 |
* Delete the regular expression and its target.
|
|
84 |
* @param re The regular expression to be deleted from the pool.
|
|
85 |
* must begin or end with a '*'
|
|
86 |
* @return target - the old target.
|
|
87 |
*/
|
|
88 |
public Object delete(String re) {
|
|
89 |
Object o = null;
|
|
90 |
RegexpNode p = prefixMachine;
|
|
91 |
RegexpNode best = p;
|
|
92 |
int len = re.length() - 1;
|
|
93 |
int i;
|
|
94 |
boolean prefix = true;
|
|
95 |
|
|
96 |
if (!re.startsWith("*") ||
|
|
97 |
!re.endsWith("*"))
|
|
98 |
len++;
|
|
99 |
|
|
100 |
if (len <= 0)
|
|
101 |
return null;
|
|
102 |
|
|
103 |
/* March forward through the prefix machine */
|
|
104 |
for (i = 0; p != null; i++) {
|
|
105 |
if (p.result != null && p.depth < BIG
|
|
106 |
&& (!p.exact || i == len)) {
|
|
107 |
best = p;
|
|
108 |
}
|
|
109 |
if (i >= len)
|
|
110 |
break;
|
|
111 |
p = p.find(re.charAt(i));
|
|
112 |
}
|
|
113 |
|
|
114 |
/* march backward through the suffix machine */
|
|
115 |
p = suffixMachine;
|
|
116 |
for (i = len; --i >= 0 && p != null;) {
|
|
117 |
if (p.result != null && p.depth < BIG) {
|
|
118 |
prefix = false;
|
|
119 |
best = p;
|
|
120 |
}
|
|
121 |
p = p.find(re.charAt(i));
|
|
122 |
}
|
|
123 |
|
|
124 |
// delete only if there is an exact match
|
|
125 |
if (prefix) {
|
|
126 |
if (re.equals(best.re)) {
|
|
127 |
o = best.result;
|
|
128 |
best.result = null;
|
|
129 |
|
|
130 |
}
|
|
131 |
} else {
|
|
132 |
if (re.equals(best.re)) {
|
|
133 |
o = best.result;
|
|
134 |
best.result = null;
|
|
135 |
}
|
|
136 |
}
|
|
137 |
return o;
|
|
138 |
}
|
|
139 |
|
|
140 |
/** Search for a match to a string & return the object associated
|
|
141 |
with it with the match. When multiple regular expressions
|
|
142 |
would match the string, the best match is returned first.
|
|
143 |
The next best match is returned the next time matchNext is
|
|
144 |
called.
|
|
145 |
@param s The string to match against the regular expressions
|
|
146 |
in the pool.
|
|
147 |
@return null on failure, otherwise the object associated with
|
|
148 |
the regular expression when it was added to the pool.
|
|
149 |
If the object is an instance of RegexpTarget, then
|
|
150 |
the return value is the result from calling
|
|
151 |
return.found(string_that_matched_wildcard).
|
|
152 |
*/
|
|
153 |
public Object match(String s) {
|
|
154 |
return matchAfter(s, BIG);
|
|
155 |
}
|
|
156 |
|
|
157 |
/** Identical to match except that it will only find matches to
|
|
158 |
regular expressions that were added to the pool <i>after</i>
|
|
159 |
the last regular expression that matched in the last call
|
|
160 |
to match() or matchNext() */
|
|
161 |
public Object matchNext(String s) {
|
|
162 |
return matchAfter(s, lastDepth);
|
|
163 |
}
|
|
164 |
|
|
165 |
private void add(String re, Object ret, boolean replace) throws REException {
|
|
166 |
int len = re.length();
|
|
167 |
RegexpNode p;
|
|
168 |
if (re.charAt(0) == '*') {
|
|
169 |
p = suffixMachine;
|
|
170 |
while (len > 1)
|
|
171 |
p = p.add(re.charAt(--len));
|
|
172 |
} else {
|
|
173 |
boolean exact = false;
|
|
174 |
if (re.charAt(len - 1) == '*')
|
|
175 |
len--;
|
|
176 |
else
|
|
177 |
exact = true;
|
|
178 |
p = prefixMachine;
|
|
179 |
for (int i = 0; i < len; i++)
|
|
180 |
p = p.add(re.charAt(i));
|
|
181 |
p.exact = exact;
|
|
182 |
}
|
|
183 |
|
|
184 |
if (p.result != null && !replace)
|
|
185 |
throw new REException(re + " is a duplicate");
|
|
186 |
|
|
187 |
p.re = re;
|
|
188 |
p.result = ret;
|
|
189 |
}
|
|
190 |
|
|
191 |
private Object matchAfter(String s, int lastMatchDepth) {
|
|
192 |
RegexpNode p = prefixMachine;
|
|
193 |
RegexpNode best = p;
|
|
194 |
int bst = 0;
|
|
195 |
int bend = 0;
|
|
196 |
int len = s.length();
|
|
197 |
int i;
|
|
198 |
if (len <= 0)
|
|
199 |
return null;
|
|
200 |
/* March forward through the prefix machine */
|
|
201 |
for (i = 0; p != null; i++) {
|
|
202 |
if (p.result != null && p.depth < lastMatchDepth
|
|
203 |
&& (!p.exact || i == len)) {
|
|
204 |
lastDepth = p.depth;
|
|
205 |
best = p;
|
|
206 |
bst = i;
|
|
207 |
bend = len;
|
|
208 |
}
|
|
209 |
if (i >= len)
|
|
210 |
break;
|
|
211 |
p = p.find(s.charAt(i));
|
|
212 |
}
|
|
213 |
/* march backward through the suffix machine */
|
|
214 |
p = suffixMachine;
|
|
215 |
for (i = len; --i >= 0 && p != null;) {
|
|
216 |
if (p.result != null && p.depth < lastMatchDepth) {
|
|
217 |
lastDepth = p.depth;
|
|
218 |
best = p;
|
|
219 |
bst = 0;
|
|
220 |
bend = i+1;
|
|
221 |
}
|
|
222 |
p = p.find(s.charAt(i));
|
|
223 |
}
|
|
224 |
Object o = best.result;
|
|
225 |
if (o != null && o instanceof RegexpTarget)
|
|
226 |
o = ((RegexpTarget) o).found(s.substring(bst, bend));
|
|
227 |
return o;
|
|
228 |
}
|
|
229 |
|
|
230 |
/** Resets the pool so that the next call to matchNext looks
|
|
231 |
at all regular expressions in the pool. match(s); is equivalent
|
|
232 |
to reset(); matchNext(s);
|
|
233 |
<p><b>Multithreading note:</b> reset/nextMatch leave state in the
|
|
234 |
regular expression pool. If multiple threads could be using this
|
|
235 |
pool this way, they should be syncronized to avoid race hazards.
|
|
236 |
match() was done in such a way that there are no such race
|
|
237 |
hazards: multiple threads can be matching in the same pool
|
|
238 |
simultaneously. */
|
|
239 |
public void reset() {
|
|
240 |
lastDepth = BIG;
|
|
241 |
}
|
|
242 |
|
|
243 |
/** Print this pool to standard output */
|
|
244 |
public void print(PrintStream out) {
|
|
245 |
out.print("Regexp pool:\n");
|
|
246 |
if (suffixMachine.firstchild != null) {
|
|
247 |
out.print(" Suffix machine: ");
|
|
248 |
suffixMachine.firstchild.print(out);
|
|
249 |
out.print("\n");
|
|
250 |
}
|
|
251 |
if (prefixMachine.firstchild != null) {
|
|
252 |
out.print(" Prefix machine: ");
|
|
253 |
prefixMachine.firstchild.print(out);
|
|
254 |
out.print("\n");
|
|
255 |
}
|
|
256 |
}
|
|
257 |
|
|
258 |
}
|
|
259 |
|
|
260 |
/* A node in a regular expression finite state machine. */
|
|
261 |
class RegexpNode {
|
|
262 |
char c;
|
|
263 |
RegexpNode firstchild;
|
|
264 |
RegexpNode nextsibling;
|
|
265 |
int depth;
|
|
266 |
boolean exact;
|
|
267 |
Object result;
|
|
268 |
String re = null;
|
|
269 |
|
|
270 |
RegexpNode () {
|
|
271 |
c = '#';
|
|
272 |
depth = 0;
|
|
273 |
}
|
|
274 |
RegexpNode (char C, int depth) {
|
|
275 |
c = C;
|
|
276 |
this.depth = depth;
|
|
277 |
}
|
|
278 |
RegexpNode add(char C) {
|
|
279 |
RegexpNode p = firstchild;
|
|
280 |
if (p == null)
|
|
281 |
p = new RegexpNode (C, depth+1);
|
|
282 |
else {
|
|
283 |
while (p != null)
|
|
284 |
if (p.c == C)
|
|
285 |
return p;
|
|
286 |
else
|
|
287 |
p = p.nextsibling;
|
|
288 |
p = new RegexpNode (C, depth+1);
|
|
289 |
p.nextsibling = firstchild;
|
|
290 |
}
|
|
291 |
firstchild = p;
|
|
292 |
return p;
|
|
293 |
}
|
|
294 |
RegexpNode find(char C) {
|
|
295 |
for (RegexpNode p = firstchild;
|
|
296 |
p != null;
|
|
297 |
p = p.nextsibling)
|
|
298 |
if (p.c == C)
|
|
299 |
return p;
|
|
300 |
return null;
|
|
301 |
}
|
|
302 |
void print(PrintStream out) {
|
|
303 |
if (nextsibling != null) {
|
|
304 |
RegexpNode p = this;
|
|
305 |
out.print("(");
|
|
306 |
while (p != null) {
|
|
307 |
out.write(p.c);
|
|
308 |
if (p.firstchild != null)
|
|
309 |
p.firstchild.print(out);
|
|
310 |
p = p.nextsibling;
|
|
311 |
out.write(p != null ? '|' : ')');
|
|
312 |
}
|
|
313 |
} else {
|
|
314 |
out.write(c);
|
|
315 |
if (firstchild != null)
|
|
316 |
firstchild.print(out);
|
|
317 |
}
|
|
318 |
}
|
|
319 |
}
|