Source Code Cross Referenced for SimpleExpression.java in  » XML » saxonb » net » sf » saxon » expr » 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.expr 
Source Cross Referenced  Class Diagram Java Document (Java Doc) 


001:        package net.sf.saxon.expr;
002:
003:        import net.sf.saxon.Controller;
004:        import net.sf.saxon.value.Value;
005:        import net.sf.saxon.event.SequenceOutputter;
006:        import net.sf.saxon.om.*;
007:        import net.sf.saxon.trans.XPathException;
008:        import net.sf.saxon.type.ItemType;
009:        import net.sf.saxon.type.Type;
010:        import net.sf.saxon.type.TypeHierarchy;
011:
012:        import java.io.PrintStream;
013:        import java.util.Arrays;
014:        import java.util.Iterator;
015:
016:        /**
017:         * An abstract implementation of Expression designed to make it easy to implement new expressions,
018:         * in particular, expressions to support extension instructions.
019:         */
020:
021:        public abstract class SimpleExpression extends ComputedExpression {
022:
023:            public static final Expression[] NO_ARGUMENTS = new Expression[0];
024:
025:            protected Expression[] arguments = NO_ARGUMENTS;
026:
027:            /**
028:             * Constructor
029:             */
030:
031:            public SimpleExpression() {
032:            }
033:
034:            /**
035:             * Set the immediate sub-expressions of this expression.
036:             * @param sub an array containing the sub-expressions of this expression
037:             */
038:
039:            public void setArguments(Expression[] sub) {
040:                arguments = sub;
041:                for (int i = 0; i < sub.length; i++) {
042:                    adoptChildExpression(sub[i]);
043:                }
044:            }
045:
046:            /**
047:             * Get the immediate sub-expressions of this expression.
048:             * @return an array containing the sub-expressions of this expression
049:             */
050:
051:            public Iterator iterateSubExpressions() {
052:                return Arrays.asList(arguments).iterator();
053:            }
054:
055:            /**
056:             * Simplify the expression
057:             * @return the simplified expression
058:             */
059:
060:            public Expression simplify(StaticContext env) throws XPathException {
061:                for (int i = 0; i < arguments.length; i++) {
062:                    if (arguments[i] != null) {
063:                        arguments[i] = arguments[i].simplify(env);
064:                    }
065:                }
066:                return this ;
067:            }
068:
069:            public Expression typeCheck(StaticContext env,
070:                    ItemType contextItemType) throws XPathException {
071:                for (int i = 0; i < arguments.length; i++) {
072:                    if (arguments[i] != null) {
073:                        arguments[i] = arguments[i].typeCheck(env,
074:                                contextItemType);
075:                    }
076:                }
077:                return this ;
078:            }
079:
080:            public Expression optimize(Optimizer opt, StaticContext env,
081:                    ItemType contextItemType) throws XPathException {
082:                for (int i = 0; i < arguments.length; i++) {
083:                    if (arguments[i] != null) {
084:                        arguments[i] = arguments[i].optimize(opt, env,
085:                                contextItemType);
086:                    }
087:                }
088:                return this ;
089:            }
090:
091:            /**
092:             * Offer promotion for this subexpression. The offer will be accepted if the subexpression
093:             * is not dependent on the factors (e.g. the context item) identified in the PromotionOffer.
094:             * By default the offer is not accepted - this is appropriate in the case of simple expressions
095:             * such as constant values and variable references where promotion would give no performance
096:             * advantage. This method is always called at compile time.
097:             *
098:             * @param offer details of the offer, for example the offer to move
099:             *     expressions that don't depend on the context to an outer level in
100:             *     the containing expression
101:             * @exception XPathException if any error is detected
102:             * @return if the offer is not accepted, return this expression unchanged.
103:             *      Otherwise return the result of rewriting the expression to promote
104:             *      this subexpression
105:             */
106:
107:            public Expression promote(PromotionOffer offer)
108:                    throws XPathException {
109:                for (int i = 0; i < arguments.length; i++) {
110:                    if (arguments[i] != null) {
111:                        arguments[i] = doPromotion(arguments[i], offer);
112:                    }
113:                }
114:                return this ;
115:            }
116:
117:            /**
118:             * Determine the data type of the items returned by this expression. This implementation
119:             * returns "item()", which can be overridden in a subclass.
120:             * @return the data type
121:             * @param th
122:             */
123:
124:            public ItemType getItemType(TypeHierarchy th) {
125:                return Type.ITEM_TYPE;
126:            }
127:
128:            /**
129:             * Determine the static cardinality of the expression. This implementation
130:             * returns "zero or more", which can be overridden in a subclass.
131:             */
132:
133:            public int computeCardinality() {
134:                if ((getImplementationMethod() & Expression.EVALUATE_METHOD) == 0) {
135:                    return StaticProperty.ALLOWS_ONE_OR_MORE;
136:                } else {
137:                    return StaticProperty.ALLOWS_ZERO_OR_ONE;
138:                }
139:            }
140:
141:            /**
142:             * Compute the dependencies of an expression, as the union of the
143:             * dependencies of its subexpressions. (This is overridden for path expressions
144:             * and filter expressions, where the dependencies of a subexpression are not all
145:             * propogated). This method should be called only once, to compute the dependencies;
146:             * after that, getDependencies should be used.
147:             * @return the depencies, as a bit-mask
148:             */
149:
150:            public int computeDependencies() {
151:                return super .computeDependencies();
152:            }
153:
154:            /**
155:             * Evaluate an expression as a single item. This always returns either a single Item or
156:             * null (denoting the empty sequence). No conversion is done. This method should not be
157:             * used unless the static type of the expression is a subtype of "item" or "item?": that is,
158:             * it should not be called if the expression may return a sequence. There is no guarantee that
159:             * this condition will be detected.
160:             *
161:             * @param context The context in which the expression is to be evaluated
162:             * @exception XPathException if any dynamic error occurs evaluating the
163:             *     expression
164:             * @return the node or atomic value that results from evaluating the
165:             *     expression; or null to indicate that the result is an empty
166:             *     sequence
167:             */
168:
169:            public Item evaluateItem(XPathContext context)
170:                    throws XPathException {
171:                int m = getImplementationMethod();
172:                if ((m & Expression.EVALUATE_METHOD) != 0) {
173:                    dynamicError(
174:                            "evaluateItem() is not implemented in the subclass "
175:                                    + this .getClass(), context);
176:                } else if ((m & Expression.ITERATE_METHOD) != 0) {
177:                    return iterate(context).next();
178:                } else {
179:                    Controller controller = context.getController();
180:                    XPathContext c2 = context.newMinorContext();
181:                    c2.setOrigin(this );
182:                    SequenceOutputter seq = new SequenceOutputter(1);
183:                    seq.setPipelineConfiguration(controller
184:                            .makePipelineConfiguration());
185:                    c2.setTemporaryReceiver(seq);
186:                    process(c2);
187:                    return seq.getFirstItem();
188:                }
189:                return null;
190:            }
191:
192:            /**
193:             * Return an Iterator to iterate over the values of a sequence. The value of every
194:             * expression can be regarded as a sequence, so this method is supported for all
195:             * expressions. This default implementation handles iteration for expressions that
196:             * return singleton values: for non-singleton expressions, the subclass must
197:             * provide its own implementation.
198:             *
199:             * @exception XPathException if any dynamic error occurs evaluating the
200:             *     expression
201:             * @param context supplies the context for evaluation
202:             * @return a SequenceIterator that can be used to iterate over the result
203:             *     of the expression
204:             */
205:
206:            public SequenceIterator iterate(XPathContext context)
207:                    throws XPathException {
208:                int m = getImplementationMethod();
209:                if ((m & Expression.EVALUATE_METHOD) != 0) {
210:                    Item item = evaluateItem(context);
211:                    if (item == null) {
212:                        return EmptyIterator.getInstance();
213:                    } else {
214:                        return SingletonIterator.makeIterator(item);
215:                    }
216:                } else if ((m & Expression.ITERATE_METHOD) != 0) {
217:                    dynamicError(
218:                            "iterate() is not implemented in the subclass "
219:                                    + this .getClass(), context);
220:
221:                } else {
222:                    Controller controller = context.getController();
223:                    XPathContext c2 = context.newMinorContext();
224:                    c2.setOrigin(this );
225:                    SequenceOutputter seq = new SequenceOutputter();
226:                    seq.setPipelineConfiguration(controller
227:                            .makePipelineConfiguration());
228:                    c2.setTemporaryReceiver(seq);
229:
230:                    process(c2);
231:
232:                    return Value.getIterator(seq.getSequence());
233:                }
234:                return null;
235:            }
236:
237:            /**
238:             * Process the instruction, without returning any tail calls
239:             * @param context The dynamic context, giving access to the current node,
240:             * the current variables, etc.
241:             */
242:
243:            public void process(XPathContext context) throws XPathException {
244:                int m = getImplementationMethod();
245:                if ((m & Expression.EVALUATE_METHOD) == 0) {
246:                    SequenceIterator iter = iterate(context);
247:                    while (true) {
248:                        Item it = iter.next();
249:                        if (it == null)
250:                            break;
251:                        context.getReceiver().append(it, locationId,
252:                                NodeInfo.ALL_NAMESPACES);
253:                    }
254:                } else {
255:                    Item item = evaluateItem(context);
256:                    context.getReceiver().append(item, locationId,
257:                            NodeInfo.ALL_NAMESPACES);
258:                }
259:            }
260:
261:            /**
262:             * Diagnostic print of expression structure. The expression is written to the System.err
263:             * output stream
264:             *
265:             * @param level indentation level for this expression
266:             * @param out
267:             */
268:
269:            public void display(int level, NamePool pool, PrintStream out) {
270:                out.println(ExpressionTool.indent(level) + getExpressionType());
271:                for (int i = 0; i < arguments.length; i++) {
272:                    arguments[i].display(level + 1, pool, out);
273:                }
274:            }
275:
276:            /**
277:             * Return a distinguishing name for the expression, for use in diagnostics.
278:             * By default the class name is used.
279:             */
280:
281:            public String getExpressionType() {
282:                return getClass().getName();
283:            }
284:
285:        }
286:
287:        //
288:        // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
289:        // you may not use this file except in compliance with the License. You may obtain a copy of the
290:        // License at http://www.mozilla.org/MPL/
291:        //
292:        // Software distributed under the License is distributed on an "AS IS" basis,
293:        // WITHOUT WARRANTY OF ANY KIND, either express or implied.
294:        // See the License for the specific language governing rights and limitations under the License.
295:        //
296:        // The Original Code is: all this file.
297:        //
298:        // The Initial Developer of the Original Code is Michael H. Kay.
299:        //
300:        // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
301:        //
302:        // Contributor(s): none.
303:        //
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.