Source Code Cross Referenced for XPathExpressionImpl.java in  » XML » saxonb » net » sf » saxon » xpath » Java Source Code / Java DocumentationJava Source Code and Java Documentation

Java Source Code / Java Documentation
1. 6.0 JDK Core
2. 6.0 JDK Modules
3. 6.0 JDK Modules com.sun
4. 6.0 JDK Modules com.sun.java
5. 6.0 JDK Modules sun
6. 6.0 JDK Platform
7. Ajax
8. Apache Harmony Java SE
9. Aspect oriented
10. Authentication Authorization
11. Blogger System
12. Build
13. Byte Code
14. Cache
15. Chart
16. Chat
17. Code Analyzer
18. Collaboration
19. Content Management System
20. Database Client
21. Database DBMS
22. Database JDBC Connection Pool
23. Database ORM
24. Development
25. EJB Server geronimo
26. EJB Server GlassFish
27. EJB Server JBoss 4.2.1
28. EJB Server resin 3.1.5
29. ERP CRM Financial
30. ESB
31. Forum
32. GIS
33. Graphic Library
34. Groupware
35. HTML Parser
36. IDE
37. IDE Eclipse
38. IDE Netbeans
39. Installer
40. Internationalization Localization
41. Inversion of Control
42. Issue Tracking
43. J2EE
44. JBoss
45. JMS
46. JMX
47. Library
48. Mail Clients
49. Net
50. Parser
51. PDF
52. Portal
53. Profiler
54. Project Management
55. Report
56. RSS RDF
57. Rule Engine
58. Science
59. Scripting
60. Search Engine
61. Security
62. Sevlet Container
63. Source Control
64. Swing Library
65. Template Engine
66. Test Coverage
67. Testing
68. UML
69. Web Crawler
70. Web Framework
71. Web Mail
72. Web Server
73. Web Services
74. Web Services apache cxf 2.0.1
75. Web Services AXIS2
76. Wiki Engine
77. Workflow Engines
78. XML
79. XML UI
Java
Java Tutorial
Java Open Source
Jar File Download
Java Articles
Java Products
Java by API
Photoshop Tutorials
Maya Tutorials
Flash Tutorials
3ds-Max Tutorials
Illustrator Tutorials
GIMP Tutorials
C# / C Sharp
C# / CSharp Tutorial
C# / CSharp Open Source
ASP.Net
ASP.NET Tutorial
JavaScript DHTML
JavaScript Tutorial
JavaScript Reference
HTML / CSS
HTML CSS Reference
C / ANSI-C
C Tutorial
C++
C++ Tutorial
Ruby
PHP
Python
Python Tutorial
Python Open Source
SQL Server / T-SQL
SQL Server / T-SQL Tutorial
Oracle PL / SQL
Oracle PL/SQL Tutorial
PostgreSQL
SQL / MySQL
MySQL Tutorial
VB.Net
VB.Net Tutorial
Flash / Flex / ActionScript
VBA / Excel / Access / Word
XML
XML Tutorial
Microsoft Office PowerPoint 2007 Tutorial
Microsoft Office Excel 2007 Tutorial
Microsoft Office Word 2007 Tutorial
Java Source Code / Java Documentation » XML » saxonb » net.sf.saxon.xpath 
Source Cross Referenced  Class Diagram Java Document (Java Doc) 


001:        package net.sf.saxon.xpath;
002:
003:        import net.sf.saxon.Configuration;
004:        import net.sf.saxon.expr.Atomizer;
005:        import net.sf.saxon.expr.Expression;
006:        import net.sf.saxon.expr.XPathContextMajor;
007:        import net.sf.saxon.functions.NumberFn;
008:        import net.sf.saxon.instruct.SlotManager;
009:        import net.sf.saxon.om.*;
010:        import net.sf.saxon.pattern.NodeTest;
011:        import net.sf.saxon.sort.FixedSortKeyDefinition;
012:        import net.sf.saxon.sort.SortedIterator;
013:        import net.sf.saxon.trans.XPathException;
014:        import net.sf.saxon.value.*;
015:        import org.xml.sax.InputSource;
016:
017:        import javax.xml.namespace.QName;
018:        import javax.xml.transform.sax.SAXSource;
019:        import javax.xml.xpath.XPathConstants;
020:        import javax.xml.xpath.XPathExpression;
021:        import javax.xml.xpath.XPathExpressionException;
022:        import java.util.List;
023:
024:        /**
025:         * <p>The JAXP XPathExpression interface represents a compiled XPath expression that can be repeatedly
026:         * evaluated. This class is Saxon's implementation of that interface.</p>
027:         *
028:         * <p>The class also includes some methods retained from Saxon's original XPath API. When these methods
029:         * are used, the object contains the context node and other state, so it is not thread-safe.</p>
030:         *
031:         * @author Michael H. Kay
032:         */
033:
034:        public class XPathExpressionImpl implements  XPathExpression {
035:
036:            private Configuration config;
037:            private Expression expression;
038:            private NodeInfo contextNode;
039:            private SlotManager stackFrameMap;
040:            private XPathExpressionImpl sortKey = null;
041:
042:            /**
043:             * The constructor is protected, to ensure that instances can only be
044:             * created using the createExpression() method of XPathEvaluator
045:             */
046:
047:            protected XPathExpressionImpl(Expression exp, Configuration config) {
048:                expression = exp;
049:                this .config = config;
050:            }
051:
052:            /**
053:             * Define the number of slots needed for local variables within the expression.
054:             * This method is for internal use only.
055:             */
056:
057:            protected void setStackFrameMap(SlotManager map) {
058:                stackFrameMap = map;
059:            }
060:
061:            /**
062:             * Define the sort order for the results of the expression. If this method is called, then
063:             * the list returned by a subsequent call on the evaluate() method will first be sorted.
064:             * @param sortKey an XPathExpression, which will be applied to each item in the sequence;
065:             * the result of this expression determines the ordering of the list returned by the evaluate()
066:             * method. The sortKey can be null, to clear a previous sort key.
067:             */
068:
069:            public void setSortKey(XPathExpressionImpl sortKey) {
070:                this .sortKey = sortKey;
071:            }
072:
073:            /**
074:             * Set the context node for evaluating the expression. If this method is not called,
075:             * the context node will be the root of the document to which the prepared expression is
076:             * bound.
077:             */
078:
079:            public void setContextNode(NodeInfo node) {
080:                if (node == null) {
081:                    throw new NullPointerException(
082:                            "Context node cannot be null");
083:                }
084:                if (node.getNamePool() != config.getNamePool()) {
085:                    throw new IllegalArgumentException(
086:                            "Supplied node uses the wrong NamePool");
087:                }
088:                contextNode = node;
089:            }
090:
091:            /**
092:             * Execute a prepared XPath expression, returning the results as a List. The context
093:             * node must have been set previously using {@link #setContextNode(net.sf.saxon.om.NodeInfo)}.
094:             * @return The results of the expression, as a List. The List represents the sequence
095:             * of items returned by the expression. Each item in the list will either be an instance
096:             * of net.sf.saxon.om.NodeInfo, representing a node, or a Java object representing an atomic value.
097:             * For the types of Java object that may be returned, see {@link #evaluate(Object, javax.xml.namespace.QName)}
098:             * with the second argument set to NODESET.
099:             */
100:
101:            public List evaluate() throws XPathException {
102:                XPathContextMajor context = new XPathContextMajor(contextNode,
103:                        config);
104:                context.openStackFrame(stackFrameMap);
105:                SequenceIterator iter = expression.iterate(context);
106:                SequenceExtent extent = new SequenceExtent(iter);
107:                return (List) extent.convertToJava(Object.class, context);
108:            }
109:
110:            /**
111:             * Execute a prepared XPath expression, returning the first item in the result.
112:             * This is useful where it is known that the expression will only return
113:             * a singleton value (for example, a single node, or a boolean). The context node
114:             * must be set previously using {@link #setContextNode(net.sf.saxon.om.NodeInfo)}.
115:             * @return The first item in the sequence returned by the expression. If the expression
116:             * returns an empty sequence, this method returns null. Otherwise, it returns the first
117:             * item in the result sequence, represented as a Java object using the same mapping as for
118:             * the evaluate() method
119:             */
120:
121:            public Object evaluateSingle() throws XPathException {
122:                XPathContextMajor context = new XPathContextMajor(contextNode,
123:                        config);
124:                context.openStackFrame(stackFrameMap);
125:                SequenceIterator iterator = expression.iterate(context);
126:                Item item = iterator.next();
127:                if (item == null) {
128:                    return null;
129:                } else {
130:                    return Value.convert(item);
131:                }
132:            }
133:
134:            /**
135:             * Get a raw iterator over the results of the expression. This returns results without
136:             * any conversion of the returned items to "native" Java classes. This method is intended
137:             * for use by applications that need to process the results of the expression using
138:             * internal Saxon interfaces.
139:             */
140:
141:            public SequenceIterator rawIterator() throws XPathException {
142:                XPathContextMajor context = new XPathContextMajor(contextNode,
143:                        config);
144:                context.openStackFrame(stackFrameMap);
145:                SequenceIterator iterator = expression.iterate(context);
146:                if (sortKey != null) {
147:                    Expression key = sortKey.expression;
148:                    if (key
149:                            .getItemType(config.getNamePool()
150:                                    .getTypeHierarchy()) instanceof  NodeTest) {
151:                        key = new Atomizer(key, config);
152:                    }
153:
154:                    FixedSortKeyDefinition[] sk = new FixedSortKeyDefinition[1];
155:
156:                    sk[0] = new FixedSortKeyDefinition();
157:                    sk[0].setSortKey(key);
158:                    sk[0].bindComparer(context);
159:
160:                    iterator = new SortedIterator(context, iterator, sk);
161:                }
162:                return iterator;
163:            }
164:
165:            /**
166:             * JAXP 1.3 evaluate() method
167:             * @param node The context node. This must use a representation of nodes that this implementation understands.
168:             * This may be a Saxon NodeInfo, or a node in one of the external object models supported, for example
169:             * DOM, JDOM, or XOM, provided the support module for that object model is loaded.
170:             * @param qName Indicates the type of result required. This must be one of the constants defined in
171:             * the JAXP {@link XPathConstants} class.
172:             * Saxon will attempt to convert the actual result of the expression to the required type using the
173:             * XPath 1.0 conversion rules.
174:             * @return the result of the evaluation, as a Java object of the appropriate type. Saxon interprets the
175:             * rules as follows:
176:             * <table>
177:             * <thead><tr><td>QName</td><td>Return Value</td></thead>
178:             * <tbody>
179:             *   <tr><td>BOOLEAN</td>
180:             *       <td>The effective boolean value of the actual result,
181:             *           as a Java Boolean object</td></tr>
182:             *   <tr><td>STRING</td>
183:             *       <td>The result of applying the string() function to the actual result,
184:             *           as a Java String object</td></tr>
185:             *   <tr><td>NUMBER</td>
186:             *       <td>The result of applying the number() function to the actual result,
187:             *           as a Java Double object</td></tr>
188:             *   <tr><td>NODE</td>
189:             *       <td>A single node, in the native data model supplied as input. If the
190:             *           expression returns more than one node, the first is returned. If
191:             *           the expression returns an empty sequence, null is returned. If the
192:             *           expression returns an atomic value, or if the first item in the
193:             *           result sequence is an atomic value, an exception is thrown.</td></tr>
194:             *   <tr><td>NODESET</td>
195:             *       <td>This is interpreted as allowing any sequence, of nodes or atomic values.
196:             *           The result is returned as a Java List object, unless it is empty, in which
197:             *           case null is returned. The contents of the list may be node objects (in the
198:             *           native data model supplied as input, or Java objects representing the XPath
199:             *           atomic values in the actual result: String for an xs:string, Double for a xs:double,
200:             *           Long for an xs:integer, and so on. (For safety, cast the values to a type
201:             *           such as xs:string within the XPath expression). Note that the result is never
202:             *           returned as a DOM NodeList.</td></tr></table>
203:             *
204:             * @throws XPathExpressionException if evaluation of the expression fails or if the
205:             * result cannot be converted to the requested type.
206:             */
207:            public Object evaluate(Object node, QName qName)
208:                    throws XPathExpressionException {
209:                ExternalObjectModel model = null;
210:                if (node instanceof  NodeInfo) {
211:                    setContextNode((NodeInfo) node);
212:                } else {
213:                    model = config.findExternalObjectModel(node);
214:                    if (model == null) {
215:                        throw new XPathExpressionException(
216:                                "Cannot locate an object model implementation for nodes of class "
217:                                        + node.getClass().getName());
218:                    }
219:                    DocumentInfo doc = model.wrapDocument(node, "", config);
220:                    NodeInfo startNode = model.wrapNode(doc, node);
221:                    setContextNode(startNode);
222:                }
223:                XPathContextMajor context = new XPathContextMajor(contextNode,
224:                        config);
225:                context.openStackFrame(stackFrameMap);
226:                try {
227:                    if (qName.equals(XPathConstants.BOOLEAN)) {
228:                        return Boolean.valueOf(expression
229:                                .effectiveBooleanValue(context));
230:                    } else if (qName.equals(XPathConstants.STRING)) {
231:                        SequenceIterator iter = expression.iterate(context);
232:
233:                        Item first = iter.next();
234:                        if (first == null) {
235:                            return "";
236:                        }
237:                        return first.getStringValue();
238:
239:                    } else if (qName.equals(XPathConstants.NUMBER)) {
240:                        SequenceIterator iter = new Atomizer(expression, config)
241:                                .iterate(context);
242:
243:                        Item first = iter.next();
244:                        if (first == null) {
245:                            return new Double(Double.NaN);
246:                        }
247:                        if (first instanceof  NumericValue) {
248:                            return new Double(((NumericValue) first)
249:                                    .getDoubleValue());
250:                        } else {
251:                            DoubleValue v = NumberFn
252:                                    .convert((AtomicValue) first);
253:                            return new Double(v.getDoubleValue());
254:                        }
255:
256:                    } else if (qName.equals(XPathConstants.NODE)) {
257:                        SequenceIterator iter = expression.iterate(context);
258:                        Item first = iter.next();
259:                        if (first instanceof  VirtualNode) {
260:                            return ((VirtualNode) first).getUnderlyingNode();
261:                        }
262:                        if (first == null || first instanceof  NodeInfo) {
263:                            return first;
264:                        }
265:                        throw new XPathExpressionException(
266:                                "Expression result is not a node");
267:                    } else if (qName.equals(XPathConstants.NODESET)) {
268:                        SequenceIterator iter = expression.iterate(context);
269:                        SequenceExtent extent = new SequenceExtent(iter);
270:                        if (model != null) {
271:                            Object result = model.convertToNodeList(extent);
272:                            if (result != null) {
273:                                return result;
274:                            }
275:                        }
276:                        return extent.convertToJava(List.class, context);
277:                    } else {
278:                        throw new IllegalArgumentException(
279:                                "Unknown type for expected result");
280:                    }
281:                } catch (XPathException e) {
282:                    throw new XPathExpressionException(e);
283:                }
284:            }
285:
286:            /**
287:             * Evaluate the expression to return a string value
288:             * @param node the initial context node. This must be an instance of NodeInfo
289:             * @return the results of the expression, converted to a String
290:             * @throws XPathExpressionException if evaluation fails
291:             */
292:
293:            public String evaluate(Object node) throws XPathExpressionException {
294:                return (String) evaluate(node, XPathConstants.STRING);
295:            }
296:
297:            /**
298:             * Evaluate the XPath expression against an input source to obtain a result of a specified type
299:             * @param inputSource The input source document against which the expression is evaluated.
300:             * (Note that there is no caching. This will be parsed, and the parsed result will be discarded.)
301:             * @param qName The type required, identified by a constant in {@link XPathConstants}
302:             * @return the result of the evaluation, as a Java object of the appropriate type:
303:             * see {@link #evaluate(Object, javax.xml.namespace.QName)}
304:             * @throws XPathExpressionException
305:             */
306:            public Object evaluate(InputSource inputSource, QName qName)
307:                    throws XPathExpressionException {
308:                try {
309:                    NodeInfo doc = new XPathEvaluator()
310:                            .setSource(new SAXSource(inputSource));
311:                    return evaluate(doc, qName);
312:                } catch (XPathException e) {
313:                    throw new XPathExpressionException(e);
314:                }
315:            }
316:
317:            /**
318:             * Evaluate the XPath expression against an input source to obtain a string result
319:             * @param inputSource The input source document against which the expression is evaluated.
320:             * (Note that there is no caching. This will be parsed, and the parsed result will be discarded.)
321:             * @return the result of the evaluation, converted to a String
322:             * @throws XPathExpressionException
323:             */
324:
325:            public String evaluate(InputSource inputSource)
326:                    throws XPathExpressionException {
327:                try {
328:                    NodeInfo doc = new XPathEvaluator()
329:                            .setSource(new SAXSource(inputSource));
330:                    return (String) evaluate(doc, XPathConstants.STRING);
331:                } catch (XPathException e) {
332:                    throw new XPathExpressionException(e);
333:                }
334:            }
335:
336:            /**
337:             * Low-level method to get the internal Saxon expression object. This exposes a wide range of
338:             * internal methods that may be needed by specialized applications, and allows greater control
339:             * over the dynamic context for evaluating the expression.
340:             * @return the underlying Saxon expression object.
341:             */
342:
343:            public Expression getInternalExpression() {
344:                return expression;
345:            }
346:
347:        }
348:
349:        //
350:        // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
351:        // you may not use this file except in compliance with the License. You may obtain a copy of the
352:        // License at http://www.mozilla.org/MPL/
353:        //
354:        // Software distributed under the License is distributed on an "AS IS" basis,
355:        // WITHOUT WARRANTY OF ANY KIND, either express or implied.
356:        // See the License for the specific language governing rights and limitations under the License.
357:        //
358:        // The Original Code is: all this file.
359:
360:        // The Initial Developer of the Original Code is
361:        // Michael H. Kay.
362:        //
363:        // Contributor(s):
364:        //
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.