Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
TranslateFunction |
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1 | /* | |
2 | * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/TranslateFunction.java,v 1.10 2006/02/05 21:47:41 elharo Exp $ | |
3 | * $Revision: 1.10 $ | |
4 | * $Date: 2006/02/05 21:47:41 $ | |
5 | * | |
6 | * ==================================================================== | |
7 | * | |
8 | * Copyright 2000-2002 bob mcwhirter & James Strachan. | |
9 | * All rights reserved. | |
10 | * | |
11 | * Redistribution and use in source and binary forms, with or without | |
12 | * modification, are permitted provided that the following conditions are | |
13 | * met: | |
14 | * | |
15 | * * Redistributions of source code must retain the above copyright | |
16 | * notice, this list of conditions and the following disclaimer. | |
17 | * | |
18 | * * Redistributions in binary form must reproduce the above copyright | |
19 | * notice, this list of conditions and the following disclaimer in the | |
20 | * documentation and/or other materials provided with the distribution. | |
21 | * | |
22 | * * Neither the name of the Jaxen Project nor the names of its | |
23 | * contributors may be used to endorse or promote products derived | |
24 | * from this software without specific prior written permission. | |
25 | * | |
26 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS | |
27 | * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED | |
28 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A | |
29 | * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER | |
30 | * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
31 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
32 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
33 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF | |
34 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
35 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
36 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
37 | * | |
38 | * ==================================================================== | |
39 | * This software consists of voluntary contributions made by many | |
40 | * individuals on behalf of the Jaxen Project and was originally | |
41 | * created by bob mcwhirter <bob@werken.com> and | |
42 | * James Strachan <jstrachan@apache.org>. For more information on the | |
43 | * Jaxen Project, please see <http://www.jaxen.org/>. | |
44 | * | |
45 | * $Id: TranslateFunction.java,v 1.10 2006/02/05 21:47:41 elharo Exp $ | |
46 | */ | |
47 | ||
48 | ||
49 | package org.jaxen.function; | |
50 | ||
51 | import java.util.HashMap; | |
52 | import java.util.List; | |
53 | import java.util.Map; | |
54 | ||
55 | import org.jaxen.Context; | |
56 | import org.jaxen.Function; | |
57 | import org.jaxen.FunctionCallException; | |
58 | import org.jaxen.Navigator; | |
59 | ||
60 | /** | |
61 | * <p> | |
62 | * <b>4.2</b> | |
63 | * <code><i>string</i> translate(<i>string</i>,<i>string</i>,<i>string</i>)</code> | |
64 | * </p> | |
65 | * | |
66 | * <blockquote src="http://www.w3.org/TR/xpath#function-translate"> | |
67 | * <p> | |
68 | * The <b><a href="http://www.w3.org/TR/xpath#function-translate">translate</a></b> function | |
69 | * returns the first argument string with occurrences of characters in | |
70 | * the second argument string replaced by the character at the | |
71 | * corresponding position in the third argument string. For example, | |
72 | * <code>translate("bar","abc","ABC")</code> returns the string | |
73 | * <code>BAr</code>. If there is a character in the second argument | |
74 | * string with no character at a corresponding position in the third | |
75 | * argument string (because the second argument string is longer than | |
76 | * the third argument string), then occurrences of that character in the | |
77 | * first argument string are removed. For example, | |
78 | * <code>translate("--aaa--","abc-","ABC")</code> returns | |
79 | * <code>"AAA"</code>. If a character occurs more than once in the | |
80 | * second argument string, then the first occurrence determines the | |
81 | * replacement character. If the third argument string is longer than | |
82 | * the second argument string, then excess characters are ignored. | |
83 | * </p> | |
84 | * | |
85 | * <blockquote> <b>NOTE: </b>The <b>translate</b> function is not a | |
86 | * sufficient solution for case conversion in all languages. A future | |
87 | * version of XPath may provide additional functions for case | |
88 | * conversion.</blockquote> | |
89 | * | |
90 | * </blockquote> | |
91 | * | |
92 | * @author Jan Dvorak ( jan.dvorak @ mathan.cz ) | |
93 | * | |
94 | * @see <a href="http://www.w3.org/TR/xpath#function-translate" | |
95 | * target="_top">Section 4.2 of the XPath Specification</a> | |
96 | */ | |
97 | public class TranslateFunction implements Function | |
98 | { | |
99 | ||
100 | /* The translation is done thru a HashMap. Performance tip (for anyone | |
101 | * who needs to improve the performance of this particular function): | |
102 | * Cache the HashMaps, once they are constructed. */ | |
103 | ||
104 | /** | |
105 | * Create a new <code>TranslateFunction</code> object. | |
106 | */ | |
107 | 106 | public TranslateFunction() {} |
108 | ||
109 | ||
110 | /** Returns a copy of the first argument in which | |
111 | * characters found in the second argument are replaced by | |
112 | * corresponding characters from the third argument. | |
113 | * | |
114 | * @param context the context at the point in the | |
115 | * expression when the function is called | |
116 | * @param args a list that contains exactly three items | |
117 | * | |
118 | * @return a <code>String</code> built from <code>args.get(0)</code> | |
119 | * in which occurrences of characters in <code>args.get(1)</code> | |
120 | * are replaced by the corresponding characters in <code>args.get(2)</code> | |
121 | * | |
122 | * @throws FunctionCallException if <code>args</code> does not have exactly three items | |
123 | */ | |
124 | public Object call(Context context, | |
125 | List args) throws FunctionCallException | |
126 | { | |
127 | 102 | if (args.size() == 3) { |
128 | 100 | return evaluate( args.get(0), |
129 | args.get(1), | |
130 | args.get(2), | |
131 | context.getNavigator() ); | |
132 | } | |
133 | ||
134 | 2 | throw new FunctionCallException( "translate() requires three arguments." ); |
135 | } | |
136 | ||
137 | /** | |
138 | * Returns a copy of <code>strArg</code> in which | |
139 | * characters found in <code>fromArg</code> are replaced by | |
140 | * corresponding characters from <code>toArg</code>. | |
141 | * If necessary each argument is first converted to it string-value | |
142 | * as if by the XPath <code>string()</code> function. | |
143 | * | |
144 | * @param strArg the base string | |
145 | * @param fromArg the characters to be replaced | |
146 | * @param toArg the characters they will be replaced by | |
147 | * @param nav the <code>Navigator</code> used to calculate the string-values of the arguments. | |
148 | * | |
149 | * @return a copy of <code>strArg</code> in which | |
150 | * characters found in <code>fromArg</code> are replaced by | |
151 | * corresponding characters from <code>toArg</code> | |
152 | * | |
153 | * @throws FunctionCallException if one of the arguments is a malformed Unicode string; | |
154 | * that is, if surrogate characters don't line up properly | |
155 | * | |
156 | */ | |
157 | public static String evaluate(Object strArg, | |
158 | Object fromArg, | |
159 | Object toArg, | |
160 | Navigator nav) throws FunctionCallException | |
161 | { | |
162 | 100 | String inStr = StringFunction.evaluate( strArg, nav ); |
163 | 100 | String fromStr = StringFunction.evaluate( fromArg, nav ); |
164 | 100 | String toStr = StringFunction.evaluate( toArg, nav ); |
165 | ||
166 | // Initialize the mapping in a HashMap | |
167 | 100 | Map characterMap = new HashMap(); |
168 | 100 | String[] fromCharacters = toUnicodeCharacters(fromStr); |
169 | 100 | String[] toCharacters = toUnicodeCharacters(toStr); |
170 | 96 | int fromLen = fromCharacters.length; |
171 | 96 | int toLen = toCharacters.length; |
172 | 376 | for ( int i = 0; i < fromLen; i++ ) { |
173 | 280 | String cFrom = fromCharacters[i]; |
174 | 280 | if ( characterMap.containsKey( cFrom ) ) { |
175 | // We've seen the character before, ignore | |
176 | 8 | continue; |
177 | } | |
178 | ||
179 | 272 | if ( i < toLen ) { |
180 | // Will change | |
181 | 224 | characterMap.put( cFrom, toCharacters[i] ); |
182 | 224 | } |
183 | else { | |
184 | // Will delete | |
185 | 48 | characterMap.put( cFrom, null ); |
186 | } | |
187 | } | |
188 | ||
189 | // Process the input string thru the map | |
190 | 96 | StringBuffer outStr = new StringBuffer( inStr.length() ); |
191 | 96 | String[] inCharacters = toUnicodeCharacters(inStr); |
192 | 96 | int inLen = inCharacters.length; |
193 | 438 | for ( int i = 0; i < inLen; i++ ) { |
194 | 342 | String cIn = inCharacters[i]; |
195 | 342 | if ( characterMap.containsKey( cIn ) ) { |
196 | 274 | String cTo = (String) characterMap.get( cIn ); |
197 | 274 | if ( cTo != null ) { |
198 | 226 | outStr.append( cTo ); |
199 | } | |
200 | 274 | } |
201 | else { | |
202 | 68 | outStr.append( cIn ); |
203 | } | |
204 | } | |
205 | ||
206 | 96 | return outStr.toString(); |
207 | } | |
208 | ||
209 | private static String[] toUnicodeCharacters(String s) throws FunctionCallException { | |
210 | ||
211 | 296 | String[] result = new String[s.length()]; |
212 | 296 | int stringLength = 0; |
213 | 1180 | for (int i = 0; i < s.length(); i++) { |
214 | 888 | char c1 = s.charAt(i); |
215 | 888 | if (isHighSurrogate(c1)) { |
216 | try { | |
217 | 18 | char c2 = s.charAt(i+1); |
218 | 18 | if (isLowSurrogate(c2)) { |
219 | 14 | result[stringLength] = (c1 + "" + c2).intern(); |
220 | 14 | i++; |
221 | 14 | } |
222 | else { | |
223 | 4 | throw new FunctionCallException("Mismatched surrogate pair in translate function"); |
224 | } | |
225 | } | |
226 | 0 | catch (StringIndexOutOfBoundsException ex) { |
227 | 0 | throw new FunctionCallException("High surrogate without low surrogate at end of string passed to translate function"); |
228 | 14 | } |
229 | } | |
230 | else { | |
231 | 870 | result[stringLength]=String.valueOf(c1).intern(); |
232 | } | |
233 | 884 | stringLength++; |
234 | } | |
235 | ||
236 | 292 | if (stringLength == result.length) return result; |
237 | ||
238 | // trim array | |
239 | 14 | String[] trimmed = new String[stringLength]; |
240 | 14 | System.arraycopy(result, 0, trimmed, 0, stringLength); |
241 | 14 | return trimmed; |
242 | ||
243 | } | |
244 | ||
245 | private static boolean isHighSurrogate(char c) { | |
246 | 888 | return c >= 0xD800 && c <= 0xDBFF; |
247 | } | |
248 | ||
249 | private static boolean isLowSurrogate(char c) { | |
250 | 18 | return c >= 0xDC00 && c <= 0xDFFF; |
251 | } | |
252 | ||
253 | } |