Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
StringFunction |
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| 8.4;8.4 |
1 | /* | |
2 | * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/StringFunction.java,v 1.33 2006/02/05 21:47:41 elharo Exp $ | |
3 | * $Revision: 1.33 $ | |
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: StringFunction.java,v 1.33 2006/02/05 21:47:41 elharo Exp $ | |
46 | */ | |
47 | ||
48 | ||
49 | package org.jaxen.function; | |
50 | ||
51 | import org.jaxen.Context; | |
52 | import org.jaxen.Function; | |
53 | import org.jaxen.FunctionCallException; | |
54 | import org.jaxen.Navigator; | |
55 | import org.jaxen.UnsupportedAxisException; | |
56 | import org.jaxen.JaxenRuntimeException; | |
57 | ||
58 | import java.text.DecimalFormat; | |
59 | import java.text.NumberFormat; | |
60 | import java.text.DecimalFormatSymbols; | |
61 | import java.util.List; | |
62 | import java.util.Iterator; | |
63 | import java.util.Locale; | |
64 | ||
65 | /** | |
66 | * <p> | |
67 | * <b>4.2</b> <code><i>string</i> string(<i>object</i>)</code> | |
68 | * </p> | |
69 | * | |
70 | * | |
71 | * <blockquote src="http://www.w3.org/TR/xpath"> | |
72 | * <p> | |
73 | * The <b>string</b> function converts | |
74 | * an object to a string as follows: | |
75 | * </p> | |
76 | * | |
77 | * <ul> | |
78 | * | |
79 | * <li> | |
80 | * <p> | |
81 | * A node-set is converted to a string by returning the <a | |
82 | * href="http://www.w3.org/TR/xpath#dt-string-value" target="_top">string-value</a> of the node in the node-set | |
83 | * that is first in <a href="http://www.w3.org/TR/xpath#dt-document-order" target="_top">document order</a>. If | |
84 | * the node-set is empty, an empty string is returned. | |
85 | * </p> | |
86 | * </li> | |
87 | * | |
88 | * <li> | |
89 | * <p> | |
90 | * A number is converted to a string as follows | |
91 | * </p> | |
92 | * | |
93 | * <ul> | |
94 | * | |
95 | * <li> | |
96 | * <p> | |
97 | * NaN is converted to the string <code>NaN</code> | |
98 | * </p> | |
99 | * </li> | |
100 | * | |
101 | * <li> | |
102 | * <p> | |
103 | * positive zero is converted to the string <code>0</code> | |
104 | * </p> | |
105 | * </li> | |
106 | * | |
107 | * <li> | |
108 | * | |
109 | * <p> | |
110 | * negative zero is converted to the string <code>0</code> | |
111 | * </p> | |
112 | * </li> | |
113 | * | |
114 | * <li> | |
115 | * <p> | |
116 | * positive infinity is converted to the string <code>Infinity</code> | |
117 | * </p> | |
118 | * </li> | |
119 | * | |
120 | * <li> | |
121 | * <p> | |
122 | * negative infinity is converted to the string <code>-Infinity</code> | |
123 | * | |
124 | * </p> | |
125 | * </li> | |
126 | * | |
127 | * <li> | |
128 | * <p> | |
129 | * if the number is an integer, the number is represented in decimal | |
130 | * form as a <a href="http://www.w3.org/TR/xpath#NT-Number" target="_top">Number</a> with no decimal point and | |
131 | * no leading zeros, preceded by a minus sign (<code>-</code>) if | |
132 | * the number is negative | |
133 | * </p> | |
134 | * </li> | |
135 | * | |
136 | * <li> | |
137 | * <p> | |
138 | * otherwise, the number is represented in decimal form as a Number including a decimal point with at least | |
139 | * one digit before the decimal point and at least one digit after the | |
140 | * decimal point, preceded by a minus sign (<code>-</code>) if the | |
141 | * number is negative; there must be no leading zeros before the decimal | |
142 | * point apart possibly from the one required digit immediately before | |
143 | * the decimal point; beyond the one required digit after the decimal | |
144 | * point there must be as many, but only as many, more digits as are | |
145 | * needed to uniquely distinguish the number from all other IEEE 754 | |
146 | * numeric values. | |
147 | * </p> | |
148 | * | |
149 | * </li> | |
150 | * | |
151 | * </ul> | |
152 | * | |
153 | * </li> | |
154 | * | |
155 | * <li> | |
156 | * <p> | |
157 | * The boolean false value is converted to the string <code>false</code>. | |
158 | * The boolean true value is converted to the string <code>true</code>. | |
159 | * </p> | |
160 | * </li> | |
161 | * | |
162 | * <li> | |
163 | * <p> | |
164 | * An object of a type other than the four basic types is converted to a | |
165 | * string in a way that is dependent on that type. | |
166 | * </p> | |
167 | * | |
168 | * </li> | |
169 | * | |
170 | * </ul> | |
171 | * | |
172 | * <p> | |
173 | * If the argument is omitted, it defaults to a node-set with the | |
174 | * context node as its only member. | |
175 | * </p> | |
176 | * | |
177 | * </blockquote> | |
178 | * | |
179 | * @author bob mcwhirter (bob @ werken.com) | |
180 | * @see <a href="http://www.w3.org/TR/xpath#function-string" | |
181 | * target="_top">Section 4.2 of the XPath Specification</a> | |
182 | */ | |
183 | public class StringFunction implements Function | |
184 | { | |
185 | ||
186 | 104 | private static DecimalFormat format = (DecimalFormat) NumberFormat.getInstance(Locale.ENGLISH); |
187 | ||
188 | static { | |
189 | 104 | DecimalFormatSymbols symbols = new DecimalFormatSymbols(Locale.ENGLISH); |
190 | 104 | symbols.setNaN("NaN"); |
191 | 104 | symbols.setInfinity("Infinity"); |
192 | 104 | format.setGroupingUsed(false); |
193 | 104 | format.setMaximumFractionDigits(32); |
194 | 104 | format.setDecimalFormatSymbols(symbols); |
195 | 104 | } |
196 | ||
197 | /** | |
198 | * Create a new <code>StringFunction</code> object. | |
199 | */ | |
200 | 106 | public StringFunction() {} |
201 | ||
202 | /** | |
203 | * Returns the string-value of <code>args.get(0)</code> | |
204 | * or of the context node if <code>args</code> is empty. | |
205 | * | |
206 | * @param context the context at the point in the | |
207 | * expression where the function is called | |
208 | * @param args list with zero or one element | |
209 | * | |
210 | * @return a <code>String</code> | |
211 | * | |
212 | * @throws FunctionCallException if <code>args</code> has more than one item | |
213 | */ | |
214 | public Object call(Context context, | |
215 | List args) throws FunctionCallException | |
216 | { | |
217 | 62 | int size = args.size(); |
218 | ||
219 | 62 | if ( size == 0 ) |
220 | { | |
221 | 40 | return evaluate( context.getNodeSet(), |
222 | context.getNavigator() ); | |
223 | } | |
224 | 22 | else if ( size == 1 ) |
225 | { | |
226 | 20 | return evaluate( args.get(0), |
227 | context.getNavigator() ); | |
228 | } | |
229 | ||
230 | 2 | throw new FunctionCallException( "string() takes at most argument." ); |
231 | } | |
232 | ||
233 | /** | |
234 | * Returns the XPath string-value of <code>obj</code>. | |
235 | * This operation is only defined if obj is a node, node-set, | |
236 | * <code>String</code>, <code>Number</code>, or | |
237 | * <code>Boolean</code>. For other types this function | |
238 | * returns the empty string. | |
239 | * | |
240 | * @param obj the node, node-set, string, number, or boolean | |
241 | * whose string-value is calculated | |
242 | * @param nav the navigator used to calculate the string-value | |
243 | * | |
244 | * @return a <code>String</code>. May be empty but is never null. | |
245 | */ | |
246 | public static String evaluate(Object obj, | |
247 | Navigator nav) | |
248 | { | |
249 | try | |
250 | { | |
251 | // Workaround because XOM uses lists for Text nodes | |
252 | // so we need to check for that first | |
253 | 11370 | if (nav != null && nav.isText(obj)) |
254 | { | |
255 | 68 | return nav.getTextStringValue(obj); |
256 | } | |
257 | ||
258 | 11302 | if (obj instanceof List) |
259 | { | |
260 | 530 | List list = (List) obj; |
261 | 530 | if (list.isEmpty()) |
262 | { | |
263 | 16 | return ""; |
264 | } | |
265 | // do not recurse: only first list should unwrap | |
266 | 514 | obj = list.get(0); |
267 | } | |
268 | ||
269 | 11286 | if (nav != null) { |
270 | // This stack of instanceof really suggests there's | |
271 | // a failure to take advantage of polymorphism here | |
272 | 11284 | if (nav.isElement(obj)) |
273 | { | |
274 | 1048 | return nav.getElementStringValue(obj); |
275 | } | |
276 | 10236 | else if (nav.isAttribute(obj)) |
277 | { | |
278 | 2060 | return nav.getAttributeStringValue(obj); |
279 | } | |
280 | ||
281 | 8176 | else if (nav.isDocument(obj)) |
282 | { | |
283 | 16 | Iterator childAxisIterator = nav.getChildAxisIterator(obj); |
284 | 16 | while (childAxisIterator.hasNext()) |
285 | { | |
286 | 16 | Object descendant = childAxisIterator.next(); |
287 | 16 | if (nav.isElement(descendant)) |
288 | { | |
289 | 16 | return nav.getElementStringValue(descendant); |
290 | } | |
291 | 0 | } |
292 | 0 | } |
293 | 8160 | else if (nav.isProcessingInstruction(obj)) |
294 | { | |
295 | 24 | return nav.getProcessingInstructionData(obj); |
296 | } | |
297 | 8136 | else if (nav.isComment(obj)) |
298 | { | |
299 | 2 | return nav.getCommentStringValue(obj); |
300 | } | |
301 | 8134 | else if (nav.isText(obj)) |
302 | { | |
303 | 40 | return nav.getTextStringValue(obj); |
304 | } | |
305 | 8094 | else if (nav.isNamespace(obj)) |
306 | { | |
307 | 2 | return nav.getNamespaceStringValue(obj); |
308 | } | |
309 | } | |
310 | ||
311 | 8094 | if (obj instanceof String) |
312 | { | |
313 | 7564 | return (String) obj; |
314 | } | |
315 | 530 | else if (obj instanceof Boolean) |
316 | { | |
317 | 288 | return stringValue(((Boolean) obj).booleanValue()); |
318 | } | |
319 | 242 | else if (obj instanceof Number) |
320 | { | |
321 | 238 | return stringValue(((Number) obj).doubleValue()); |
322 | } | |
323 | ||
324 | } | |
325 | 0 | catch (UnsupportedAxisException e) |
326 | { | |
327 | 0 | throw new JaxenRuntimeException(e); |
328 | 4 | } |
329 | ||
330 | 4 | return ""; |
331 | ||
332 | } | |
333 | ||
334 | private static String stringValue(double value) | |
335 | { | |
336 | ||
337 | // DecimalFormat formats negative zero as "-0". | |
338 | // Therefore we need to test for zero explicitly here. | |
339 | 238 | if (value == 0) return "0"; |
340 | ||
341 | // need to synchronize object for thread-safety | |
342 | 220 | String result = null; |
343 | 220 | synchronized (format) { |
344 | 220 | result = format.format(value); |
345 | 220 | } |
346 | 220 | return result; |
347 | ||
348 | } | |
349 | ||
350 | private static String stringValue(boolean value) | |
351 | { | |
352 | 288 | return value ? "true" : "false"; |
353 | } | |
354 | ||
355 | } |