Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
BaseXPath |
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| 1.9259259259259258;1.926 |
1 | /* | |
2 | * $Header$ | |
3 | * $Revision$ | |
4 | * $Date$ | |
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 | * $Id$ | |
46 | */ | |
47 | ||
48 | ||
49 | package org.jaxen; | |
50 | ||
51 | import java.io.Serializable; | |
52 | import java.util.List; | |
53 | ||
54 | import org.jaxen.expr.Expr; | |
55 | import org.jaxen.expr.XPathExpr; | |
56 | import org.jaxen.function.BooleanFunction; | |
57 | import org.jaxen.function.NumberFunction; | |
58 | import org.jaxen.function.StringFunction; | |
59 | import org.jaxen.saxpath.SAXPathException; | |
60 | import org.jaxen.saxpath.XPathReader; | |
61 | import org.jaxen.saxpath.helpers.XPathReaderFactory; | |
62 | import org.jaxen.util.SingletonList; | |
63 | ||
64 | /** Base functionality for all concrete, implementation-specific XPaths. | |
65 | * | |
66 | * <p> | |
67 | * This class provides generic functionality for further-defined | |
68 | * implementation-specific XPaths. | |
69 | * </p> | |
70 | * | |
71 | * <p> | |
72 | * If you want to adapt the Jaxen engine to traverse your own | |
73 | * object model, then this is a good base class to derive from. | |
74 | * Typically you only really need to provide your own | |
75 | * {@link org.jaxen.Navigator} implementation. | |
76 | * </p> | |
77 | * | |
78 | * @see org.jaxen.dom4j.Dom4jXPath XPath for dom4j | |
79 | * @see org.jaxen.jdom.JDOMXPath XPath for JDOM | |
80 | * @see org.jaxen.dom.DOMXPath XPath for W3C DOM | |
81 | * | |
82 | * @author <a href="mailto:bob@werken.com">bob mcwhirter</a> | |
83 | * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> | |
84 | */ | |
85 | public class BaseXPath implements XPath, Serializable | |
86 | { | |
87 | ||
88 | private static final long serialVersionUID = -1993731281300293168L; | |
89 | ||
90 | /** Original expression text. */ | |
91 | private final String exprText; | |
92 | ||
93 | /** the parsed form of the XPath expression */ | |
94 | private final XPathExpr xpath; | |
95 | ||
96 | /** the support information and function, namespace and variable contexts */ | |
97 | private ContextSupport support; | |
98 | ||
99 | /** the implementation-specific Navigator for retrieving XML nodes **/ | |
100 | private Navigator navigator; | |
101 | ||
102 | /** Construct given an XPath expression string. | |
103 | * | |
104 | * @param xpathExpr the XPath expression | |
105 | * | |
106 | * @throws JaxenException if there is a syntax error while | |
107 | * parsing the expression | |
108 | */ | |
109 | protected BaseXPath(String xpathExpr) throws JaxenException | |
110 | 6146 | { |
111 | try | |
112 | { | |
113 | 6146 | XPathReader reader = XPathReaderFactory.createReader(); |
114 | 6144 | JaxenHandler handler = new JaxenHandler(); |
115 | 6144 | reader.setXPathHandler( handler ); |
116 | 6144 | reader.parse( xpathExpr ); |
117 | 6064 | this.xpath = handler.getXPathExpr(); |
118 | } | |
119 | 80 | catch (org.jaxen.saxpath.XPathSyntaxException e) |
120 | { | |
121 | 80 | throw new org.jaxen.XPathSyntaxException( e ); |
122 | } | |
123 | 2 | catch (SAXPathException e) |
124 | { | |
125 | 2 | throw new JaxenException( e ); |
126 | 6064 | } |
127 | ||
128 | 6064 | this.exprText = xpathExpr; |
129 | 6064 | } |
130 | ||
131 | /** Construct given an XPath expression string. | |
132 | * | |
133 | * @param xpathExpr the XPath expression | |
134 | * | |
135 | * @param navigator the XML navigator to use | |
136 | * | |
137 | * @throws JaxenException if there is a syntax error while | |
138 | * parsing the expression | |
139 | */ | |
140 | public BaseXPath(String xpathExpr, Navigator navigator) throws JaxenException | |
141 | { | |
142 | 6146 | this( xpathExpr ); |
143 | 6064 | this.navigator = navigator; |
144 | 6064 | } |
145 | ||
146 | /** Evaluate this XPath against a given context. | |
147 | * The context of evaluation may be any object type | |
148 | * the navigator recognizes as a node. | |
149 | * The return value is either a <code>String</code>, | |
150 | * <code>Double</code>, <code>Boolean</code>, or <code>List</code> | |
151 | * of nodes. | |
152 | * | |
153 | * <p> | |
154 | * When using this method, one must be careful to | |
155 | * test the class of the returned object. If the returned | |
156 | * object is a list, then the items in this | |
157 | * list will be the actual <code>Document</code>, | |
158 | * <code>Element</code>, <code>Attribute</code>, etc. objects | |
159 | * as defined by the concrete XML object-model implementation, | |
160 | * directly from the context document. This method <strong>does | |
161 | * not return <em>copies</em> of anything</strong>, but merely | |
162 | * returns references to objects within the source document. | |
163 | * </p> | |
164 | * | |
165 | * @param context the node, node-set or Context object for evaluation. | |
166 | * This value can be null. | |
167 | * | |
168 | * @return the result of evaluating the XPath expression | |
169 | * against the supplied context | |
170 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
171 | * @throws ClassCastException if the context is not a node | |
172 | */ | |
173 | public Object evaluate(Object context) throws JaxenException | |
174 | { | |
175 | 1712 | List answer = selectNodes(context); |
176 | ||
177 | 1692 | if ( answer != null |
178 | && | |
179 | 1692 | answer.size() == 1 ) |
180 | { | |
181 | 1680 | Object first = answer.get(0); |
182 | ||
183 | 1680 | if ( first instanceof String |
184 | || | |
185 | first instanceof Number | |
186 | || | |
187 | first instanceof Boolean ) | |
188 | { | |
189 | 1412 | return first; |
190 | } | |
191 | } | |
192 | 280 | return answer; |
193 | } | |
194 | ||
195 | /** | |
196 | * List all the nodes selected by this XPath | |
197 | * expression. If multiple nodes match, multiple nodes | |
198 | * are returned. Nodes are returned | |
199 | * in document-order, as defined by the XPath | |
200 | * specification. If the expression selects a non-node-set | |
201 | * (i.e. a number, boolean, or string) then a List | |
202 | * containing just that one object is returned. | |
203 | * | |
204 | * @param node the node, node-set or Context object for evaluation. | |
205 | * This value can be null. | |
206 | * | |
207 | * @return the node-set of all items selected by this XPath expression | |
208 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
209 | * | |
210 | * @see #selectNodesForContext | |
211 | */ | |
212 | public List selectNodes(Object node) throws JaxenException | |
213 | { | |
214 | 3650 | Context context = getContext( node ); |
215 | 3650 | return selectNodesForContext( context ); |
216 | } | |
217 | ||
218 | /** | |
219 | * Return the first node selected by this XPath | |
220 | * expression. If multiple nodes match, only one node is | |
221 | * returned. The selected node will be the first | |
222 | * selected node in document-order, as defined by the XPath | |
223 | * specification. | |
224 | * | |
225 | * @param node the node, node-set or Context object for evaluation. | |
226 | * This value can be null. | |
227 | * | |
228 | * @return the node-set of all items selected | |
229 | * by this XPath expression | |
230 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
231 | * | |
232 | * @see #selectNodes | |
233 | */ | |
234 | public Object selectSingleNode(Object node) throws JaxenException | |
235 | { | |
236 | 8 | List results = selectNodes( node ); |
237 | ||
238 | 8 | if ( results.isEmpty() ) |
239 | { | |
240 | 4 | return null; |
241 | } | |
242 | ||
243 | 4 | return results.get( 0 ); |
244 | } | |
245 | ||
246 | /** | |
247 | * Returns the XPath string-value of the argument node. | |
248 | * | |
249 | * @param node the node whose value to take | |
250 | * @return the XPath string value of this node | |
251 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
252 | * @deprecated replaced by {@link #stringValueOf} | |
253 | */ | |
254 | public String valueOf(Object node) throws JaxenException | |
255 | { | |
256 | 0 | return stringValueOf( node ); |
257 | } | |
258 | ||
259 | /** Retrieves the string-value of the result of | |
260 | * evaluating this XPath expression when evaluated | |
261 | * against the specified context. | |
262 | * | |
263 | * <p> | |
264 | * The string-value of the expression is determined per | |
265 | * the <code>string(..)</code> core function defined | |
266 | * in the XPath specification. This means that an expression | |
267 | * that selects zero nodes will return the empty string, | |
268 | * while an expression that selects one-or-more nodes will | |
269 | * return the string-value of the first node. | |
270 | * </p> | |
271 | * | |
272 | * @param node the node, node-set or Context object for evaluation. This value can be null. | |
273 | * | |
274 | * @return the string-value of the result of evaluating this expression with the specified context node | |
275 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
276 | */ | |
277 | public String stringValueOf(Object node) throws JaxenException | |
278 | { | |
279 | 6 | Context context = getContext( node ); |
280 | ||
281 | 6 | Object result = selectSingleNodeForContext( context ); |
282 | ||
283 | 6 | if ( result == null ) |
284 | { | |
285 | 2 | return ""; |
286 | } | |
287 | ||
288 | 8 | return StringFunction.evaluate( result, |
289 | 4 | context.getNavigator() ); |
290 | } | |
291 | ||
292 | /** Retrieve a boolean-value interpretation of this XPath | |
293 | * expression when evaluated against a given context. | |
294 | * | |
295 | * <p> | |
296 | * The boolean-value of the expression is determined per | |
297 | * the <code>boolean(..)</code> function defined | |
298 | * in the XPath specification. This means that an expression | |
299 | * that selects zero nodes will return <code>false</code>, | |
300 | * while an expression that selects one or more nodes will | |
301 | * return <code>true</code>. | |
302 | * </p> | |
303 | * | |
304 | * @param node the node, node-set or Context object for evaluation. This value can be null. | |
305 | * | |
306 | * @return the boolean-value of the result of evaluating this expression with the specified context node | |
307 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
308 | */ | |
309 | public boolean booleanValueOf(Object node) throws JaxenException | |
310 | { | |
311 | 8 | Context context = getContext( node ); |
312 | 8 | List result = selectNodesForContext( context ); |
313 | 8 | if ( result == null ) return false; |
314 | 8 | return BooleanFunction.evaluate( result, context.getNavigator() ).booleanValue(); |
315 | } | |
316 | ||
317 | /** Retrieve a number-value interpretation of this XPath | |
318 | * expression when evaluated against a given context. | |
319 | * | |
320 | * <p> | |
321 | * The number-value of the expression is determined per | |
322 | * the <code>number(..)</code> core function as defined | |
323 | * in the XPath specification. This means that if this | |
324 | * expression selects multiple nodes, the number-value | |
325 | * of the first node is returned. | |
326 | * </p> | |
327 | * | |
328 | * @param node the node, node-set or Context object for evaluation. This value can be null. | |
329 | * | |
330 | * @return a <code>Double</code> indicating the numeric value of | |
331 | * evaluating this expression against the specified context | |
332 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
333 | */ | |
334 | public Number numberValueOf(Object node) throws JaxenException | |
335 | { | |
336 | 6 | Context context = getContext( node ); |
337 | 6 | Object result = selectSingleNodeForContext( context ); |
338 | 12 | return NumberFunction.evaluate( result, |
339 | 6 | context.getNavigator() ); |
340 | } | |
341 | ||
342 | // Helpers | |
343 | ||
344 | /** Add a namespace prefix-to-URI mapping for this XPath | |
345 | * expression. | |
346 | * | |
347 | * <p> | |
348 | * Namespace prefix-to-URI mappings in an XPath are independent | |
349 | * of those used within any document. Only the mapping explicitly | |
350 | * added to this XPath will be available for resolving the | |
351 | * XPath expression. | |
352 | * </p> | |
353 | * | |
354 | * <p> | |
355 | * This is a convenience method for adding mappings to the | |
356 | * default {@link NamespaceContext} in place for this XPath. | |
357 | * If you have installed a custom <code>NamespaceContext</code> | |
358 | * that is not a <code>SimpleNamespaceContext</code>, | |
359 | * then this method will throw a <code>JaxenException</code>. | |
360 | * </p> | |
361 | * | |
362 | * @param prefix the namespace prefix | |
363 | * @param uri the namespace URI | |
364 | * | |
365 | * @throws JaxenException if the <code>NamespaceContext</code> | |
366 | * used by this XPath is not a <code>SimpleNamespaceContext</code> | |
367 | */ | |
368 | public void addNamespace(String prefix, | |
369 | String uri) throws JaxenException | |
370 | { | |
371 | 16 | NamespaceContext nsContext = getNamespaceContext(); |
372 | 16 | if ( nsContext instanceof SimpleNamespaceContext ) |
373 | { | |
374 | 14 | ((SimpleNamespaceContext)nsContext).addNamespace( prefix, |
375 | uri ); | |
376 | 14 | return; |
377 | } | |
378 | ||
379 | 2 | throw new JaxenException("Operation not permitted while using a non-simple namespace context."); |
380 | } | |
381 | ||
382 | ||
383 | // ------------------------------------------------------------ | |
384 | // ------------------------------------------------------------ | |
385 | // Properties | |
386 | // ------------------------------------------------------------ | |
387 | // ------------------------------------------------------------ | |
388 | ||
389 | ||
390 | /** Set a <code>NamespaceContext</code> for use with this | |
391 | * XPath expression. | |
392 | * | |
393 | * <p> | |
394 | * A <code>NamespaceContext</code> is responsible for translating | |
395 | * namespace prefixes within the expression into namespace URIs. | |
396 | * </p> | |
397 | * | |
398 | * @param namespaceContext the <code>NamespaceContext</code> to | |
399 | * install for this expression | |
400 | * | |
401 | * @see NamespaceContext | |
402 | * @see NamespaceContext#translateNamespacePrefixToUri | |
403 | */ | |
404 | public void setNamespaceContext(NamespaceContext namespaceContext) | |
405 | { | |
406 | 66 | getContextSupport().setNamespaceContext(namespaceContext); |
407 | 66 | } |
408 | ||
409 | /** Set a <code>FunctionContext</code> for use with this XPath | |
410 | * expression. | |
411 | * | |
412 | * <p> | |
413 | * A <code>FunctionContext</code> is responsible for resolving | |
414 | * all function calls used within the expression. | |
415 | * </p> | |
416 | * | |
417 | * @param functionContext the <code>FunctionContext</code> to | |
418 | * install for this expression | |
419 | * | |
420 | * @see FunctionContext | |
421 | * @see FunctionContext#getFunction | |
422 | */ | |
423 | public void setFunctionContext(FunctionContext functionContext) | |
424 | { | |
425 | 58 | getContextSupport().setFunctionContext(functionContext); |
426 | 58 | } |
427 | ||
428 | /** Set a <code>VariableContext</code> for use with this XPath | |
429 | * expression. | |
430 | * | |
431 | * <p> | |
432 | * A <code>VariableContext</code> is responsible for resolving | |
433 | * all variables referenced within the expression. | |
434 | * </p> | |
435 | * | |
436 | * @param variableContext The <code>VariableContext</code> to | |
437 | * install for this expression | |
438 | * | |
439 | * @see VariableContext | |
440 | * @see VariableContext#getVariableValue | |
441 | */ | |
442 | public void setVariableContext(VariableContext variableContext) | |
443 | { | |
444 | 58 | getContextSupport().setVariableContext(variableContext); |
445 | 58 | } |
446 | ||
447 | /** Retrieve the <code>NamespaceContext</code> used by this XPath | |
448 | * expression. | |
449 | * | |
450 | * <p> | |
451 | * A <code>NamespaceContext</code> is responsible for mapping | |
452 | * prefixes used within the expression to namespace URIs. | |
453 | * </p> | |
454 | * | |
455 | * <p> | |
456 | * If this XPath expression has not previously had a <code>NamespaceContext</code> | |
457 | * installed, a new default <code>NamespaceContext</code> will be created, | |
458 | * installed and returned. | |
459 | * </p> | |
460 | * | |
461 | * @return the <code>NamespaceContext</code> used by this expression | |
462 | * | |
463 | * @see NamespaceContext | |
464 | */ | |
465 | public NamespaceContext getNamespaceContext() | |
466 | { | |
467 | 18 | return getContextSupport().getNamespaceContext(); |
468 | } | |
469 | ||
470 | /** Retrieve the <code>FunctionContext</code> used by this XPath | |
471 | * expression. | |
472 | * | |
473 | * <p> | |
474 | * A <code>FunctionContext</code> is responsible for resolving | |
475 | * all function calls used within the expression. | |
476 | * </p> | |
477 | * | |
478 | * <p> | |
479 | * If this XPath expression has not previously had a <code>FunctionContext</code> | |
480 | * installed, a new default <code>FunctionContext</code> will be created, | |
481 | * installed and returned. | |
482 | * </p> | |
483 | * | |
484 | * @return the <code>FunctionContext</code> used by this expression | |
485 | * | |
486 | * @see FunctionContext | |
487 | */ | |
488 | public FunctionContext getFunctionContext() | |
489 | { | |
490 | 4 | return getContextSupport().getFunctionContext(); |
491 | } | |
492 | ||
493 | /** Retrieve the <code>VariableContext</code> used by this XPath | |
494 | * expression. | |
495 | * | |
496 | * <p> | |
497 | * A <code>VariableContext</code> is responsible for resolving | |
498 | * all variables referenced within the expression. | |
499 | * </p> | |
500 | * | |
501 | * <p> | |
502 | * If this XPath expression has not previously had a <code>VariableContext</code> | |
503 | * installed, a new default <code>VariableContext</code> will be created, | |
504 | * installed and returned. | |
505 | * </p> | |
506 | * | |
507 | * @return the <code>VariableContext</code> used by this expression | |
508 | * | |
509 | * @see VariableContext | |
510 | */ | |
511 | public VariableContext getVariableContext() | |
512 | { | |
513 | 2 | return getContextSupport().getVariableContext(); |
514 | } | |
515 | ||
516 | ||
517 | /** Retrieve the root expression of the internal | |
518 | * compiled form of this XPath expression. | |
519 | * | |
520 | * <p> | |
521 | * Internally, Jaxen maintains a form of Abstract Syntax | |
522 | * Tree (AST) to represent the structure of the XPath expression. | |
523 | * This is normally not required during normal consumer-grade | |
524 | * usage of Jaxen. This method is provided for hard-core users | |
525 | * who wish to manipulate or inspect a tree-based version of | |
526 | * the expression. | |
527 | * </p> | |
528 | * | |
529 | * @return the root of the AST of this expression | |
530 | */ | |
531 | public Expr getRootExpr() | |
532 | { | |
533 | 7054 | return xpath.getRootExpr(); |
534 | } | |
535 | ||
536 | /** Return the original expression text. | |
537 | * | |
538 | * @return the normalized XPath expression string | |
539 | */ | |
540 | public String toString() | |
541 | { | |
542 | 516 | return this.exprText; |
543 | } | |
544 | ||
545 | /** Returns a string representation of the parse tree. | |
546 | * | |
547 | * @return a string representation of the parse tree. | |
548 | */ | |
549 | public String debug() | |
550 | { | |
551 | 2 | return this.xpath.toString(); |
552 | } | |
553 | ||
554 | // ------------------------------------------------------------ | |
555 | // ------------------------------------------------------------ | |
556 | // Implementation methods | |
557 | // ------------------------------------------------------------ | |
558 | // ------------------------------------------------------------ | |
559 | ||
560 | ||
561 | /** Create a {@link Context} wrapper for the provided | |
562 | * implementation-specific object. | |
563 | * | |
564 | * @param node the implementation-specific object | |
565 | * to be used as the context | |
566 | * | |
567 | * @return a <code>Context</code> wrapper around the object | |
568 | */ | |
569 | protected Context getContext(Object node) | |
570 | { | |
571 | 3670 | if ( node instanceof Context ) |
572 | { | |
573 | 2448 | return (Context) node; |
574 | } | |
575 | ||
576 | 1222 | Context fullContext = new Context( getContextSupport() ); |
577 | ||
578 | 1222 | if ( node instanceof List ) |
579 | { | |
580 | 4 | fullContext.setNodeSet( (List) node ); |
581 | } | |
582 | else | |
583 | { | |
584 | 1218 | List list = new SingletonList(node); |
585 | 1218 | fullContext.setNodeSet( list ); |
586 | } | |
587 | ||
588 | 1222 | return fullContext; |
589 | } | |
590 | ||
591 | /** Retrieve the {@link ContextSupport} aggregation of | |
592 | * <code>NamespaceContext</code>, <code>FunctionContext</code>, | |
593 | * <code>VariableContext</code>, and {@link Navigator}. | |
594 | * | |
595 | * @return aggregate <code>ContextSupport</code> for this | |
596 | * XPath expression | |
597 | */ | |
598 | protected ContextSupport getContextSupport() | |
599 | { | |
600 | 1428 | if ( support == null ) |
601 | { | |
602 | 1284 | support = new ContextSupport( |
603 | 1284 | createNamespaceContext(), |
604 | 1284 | createFunctionContext(), |
605 | 1284 | createVariableContext(), |
606 | 1284 | getNavigator() |
607 | ); | |
608 | } | |
609 | ||
610 | 1428 | return support; |
611 | } | |
612 | ||
613 | /** Retrieve the XML object-model-specific {@link Navigator} | |
614 | * for us in evaluating this XPath expression. | |
615 | * | |
616 | * @return the implementation-specific <code>Navigator</code> | |
617 | */ | |
618 | public Navigator getNavigator() | |
619 | { | |
620 | 1286 | return navigator; |
621 | } | |
622 | ||
623 | ||
624 | ||
625 | // ------------------------------------------------------------ | |
626 | // ------------------------------------------------------------ | |
627 | // Factory methods for default contexts | |
628 | // ------------------------------------------------------------ | |
629 | // ------------------------------------------------------------ | |
630 | ||
631 | /** Create a default <code>FunctionContext</code>. | |
632 | * | |
633 | * @return a default <code>FunctionContext</code> | |
634 | */ | |
635 | protected FunctionContext createFunctionContext() | |
636 | { | |
637 | 1284 | return XPathFunctionContext.getInstance(); |
638 | } | |
639 | ||
640 | /** Create a default <code>NamespaceContext</code>. | |
641 | * | |
642 | * @return a default <code>NamespaceContext</code> instance | |
643 | */ | |
644 | protected NamespaceContext createNamespaceContext() | |
645 | { | |
646 | 1284 | return new SimpleNamespaceContext(); |
647 | } | |
648 | ||
649 | /** Create a default <code>VariableContext</code>. | |
650 | * | |
651 | * @return a default <code>VariableContext</code> instance | |
652 | */ | |
653 | protected VariableContext createVariableContext() | |
654 | { | |
655 | 1284 | return new SimpleVariableContext(); |
656 | } | |
657 | ||
658 | /** Select all nodes that match this XPath | |
659 | * expression on the given Context object. | |
660 | * If multiple nodes match, multiple nodes | |
661 | * will be returned in document-order, as defined by the XPath | |
662 | * specification. If the expression selects a non-node-set | |
663 | * (i.e. a number, boolean, or string) then a List | |
664 | * containing just that one object is returned. | |
665 | * | |
666 | * @param context the Context which gets evaluated | |
667 | * | |
668 | * @return the node-set of all items selected | |
669 | * by this XPath expression | |
670 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
671 | * | |
672 | */ | |
673 | protected List selectNodesForContext(Context context) throws JaxenException | |
674 | { | |
675 | 3670 | List list = this.xpath.asList( context ); |
676 | 3546 | return list; |
677 | ||
678 | } | |
679 | ||
680 | ||
681 | /** Return only the first node that is selected by this XPath | |
682 | * expression. If multiple nodes match, only one node will be | |
683 | * returned. The selected node will be the first | |
684 | * selected node in document-order, as defined by the XPath | |
685 | * specification. If the XPath expression selects a double, | |
686 | * String, or boolean, then that object is returned. | |
687 | * | |
688 | * @param context the Context against which this expression is evaluated | |
689 | * | |
690 | * @return the first node in document order of all nodes selected | |
691 | * by this XPath expression | |
692 | * @throws JaxenException if an XPath error occurs during expression evaluation | |
693 | * | |
694 | * @see #selectNodesForContext | |
695 | */ | |
696 | protected Object selectSingleNodeForContext(Context context) throws JaxenException | |
697 | { | |
698 | 12 | List results = selectNodesForContext(context); |
699 | ||
700 | 12 | if ( results.isEmpty() ) |
701 | { | |
702 | 4 | return null; |
703 | } | |
704 | ||
705 | 8 | return results.get( 0 ); |
706 | } | |
707 | ||
708 | } |