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Java > Open Source Codes > org > webharvest > runtime > processors > XPathProcessor


1 /* Copyright (c) 2006-2007, Vladimir Nikic
2     All rights reserved.
3
4     Redistribution and use of this software in source and binary forms,
5     with or without modification, are permitted provided that the following
6     conditions are met:
7
8     * Redistributions of source code must retain the above
9       copyright notice, this list of conditions and the
10       following disclaimer.
11
12     * Redistributions in binary form must reproduce the above
13       copyright notice, this list of conditions and the
14       following disclaimer in the documentation and/or other
15       materials provided with the distribution.
16
17     * The name of Web-Harvest may not be used to endorse or promote
18       products derived from this software without specific prior
19       written permission.
20
21     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22     AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24     ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
25     LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28     INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30     ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31     POSSIBILITY OF SUCH DAMAGE.
32
33     You can contact Vladimir Nikic by sending e-mail to
34     nikic_vladimir@yahoo.com. Please include the word "Web-Harvest" in the
35     subject line.
36 */
37 package org.webharvest.runtime.processors;
38
39 import java.io.StringReader JavaDoc;
40
41 import javax.xml.transform.stream.StreamSource JavaDoc;
42
43 import net.sf.saxon.Configuration;
44 import net.sf.saxon.om.Item;
45 import net.sf.saxon.om.SequenceIterator;
46 import net.sf.saxon.query.*;
47 import net.sf.saxon.trans.XPathException;
48
49 import org.webharvest.definition.XPathDef;
50 import org.webharvest.exception.ScraperXPathException;
51 import org.webharvest.runtime.Scraper;
52 import org.webharvest.runtime.ScraperContext;
53 import org.webharvest.runtime.templaters.BaseTemplater;
54 import org.webharvest.runtime.variables.*;
55 import org.webharvest.utils.CommonUtil;
56
57 /**
58  * XQuery processor.
59  */
60 public class XPathProcessor extends BaseProcessor {
61
62     private XPathDef xpathDef;
63
64     public XPathProcessor(XPathDef xpathDef) {
65         super(xpathDef);
66         this.xpathDef = xpathDef;
67     }
68
69     public IVariable execute(Scraper scraper, ScraperContext context) {
70         IVariable xml = getBodyTextContent(xpathDef, scraper, context);
71         String JavaDoc expression = BaseTemplater.execute( xpathDef.getExpression(), scraper.getScriptEngine() );
72
73         try {
74             String JavaDoc input = xml.toString();
75
76             final Configuration config = new Configuration();
77             final StaticQueryContext sqc = new StaticQueryContext(config);
78             final XQueryExpression exp = sqc.compileQuery(expression);
79             final DynamicQueryContext dynamicContext = new DynamicQueryContext(config);
80             
81             StringReader JavaDoc reader = new StringReader JavaDoc(input);
82             dynamicContext.setContextItem(sqc.buildDocument(new StreamSource JavaDoc(reader)));
83             final SequenceIterator iter = exp.iterator(dynamicContext);
84             
85             ListVariable listVariable = new ListVariable();
86             while (true) {
87                 Item item = iter.next();
88                 if (item == null) {
89                     break;
90                 }
91                 
92                 String JavaDoc value = CommonUtil.serializeItem(item, config);
93                 listVariable.addVariable( new NodeVariable(value) );
94             }
95
96             return listVariable;
97         } catch (XPathException e) {
98             e.printStackTrace();
99             throw new ScraperXPathException("Error parsing XPath expression (XPath = [" + expression + "])!", e);
100         }
101     }
102
103 }
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