5-2 Programming XML for Oracle WebLogic Server
WebLogic Server provides a full implementation of the JAXR specification. Using the JAXR API, you can create JAXR clients that access a registry, or you can create a
registry yourself.
For more information on using the JAXR API, see the Java Web Services http:java.sun.comxmljaxrindex.jsp
Web site.
5.2 Using the WebLogic XPath API
The WebLogic XPath API contains all of the classes required to perform XPath matching against a document represented as a DOM, an XMLInputStream, or an
XMLOutputStream. Use the API if you want to identify a subset of XML elements within an XML document that conform to a given pattern.
For additional API reference information about the WebLogic XPath API, see weblogic.xml.xpath in the Oracle WebLogic Server API Reference and
http:java.sun.comxmljaxrindex.jsp Javadoc.
5.2.1 Using the DOMXPath Class
This section describes how to use the DOMXPath class of the WebLogic XPath API to perform XPath matching against an XML document represented as a DOM. The section
first provides an example and then a description of the main steps used in the example.
5.2.2 Example of Using the DOMXPath Class
The sample Java program at the end of this section uses the following XML document in its matching:
?xml version=1.0 encoding=us-ascii? -- Purchaseorder. --
purchaseorder department=Sales
date=01-11-2001 raisedby=Pikachu
item ID=101
titleLaptoptitle quantity5quantity
makeDellmake item
item ID=102
titleDesktoptitle quantity15quantity
makeDellmake item
item ID=103
titleOffice Softwaretitle quantity10quantity
makeMicrosoftmake item
purchaseorder
Using Advanced XML APIs 5-3
The Java code example is as follows: package examples.xml.xpath;
import java.io.IOException; import java.util.Iterator;
import java.util.Set; import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document; import org.w3c.dom.Node;
import org.xml.sax.SAXException; import weblogic.xml.xpath.DOMXPath;
import weblogic.xml.xpath.XPathException; This class provides a simple example of how to use the DOMXPath
API. author Copyright c 2002 by BEA Systems, Inc. All Rights Reserved.
public abstract class DOMXPathExample { public static void mainString[] ignored
throws XPathException, ParserConfigurationException, SAXException, IOException
{ create a dom representation of the document
String file = purchaseorder.xml; DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance;
factory.setNamespaceAwaretrue; doesnt matter for this example DocumentBuilder builder = factory.newDocumentBuilder;
Document doc = builder.parsefile; create some instances of DOMXPath to evaluate against the
document. DOMXPath totalItems = count number of items
new DOMXPathcountpurchaseorderitem; DOMXPath atLeast10 = titles of items with quantity = 10
new DOMXPathpurchaseorderitem[quantity = 10]title; evaluate them against the document
double count = totalItems.evaluateAsNumberdoc; Set nodeset = atLeast10.evaluateAsNodesetdoc;
5-4 Programming XML for Oracle WebLogic Server
output results System.out.printlnfile+ contains +count+ total items.;
System.out.printlnThe following items have quantity = 10:; if nodeset = null {
Iterator i = nodeset.iterator; whilei.hasNext {
Node node = Nodei.next; System.out.println +node.getNodeName+
: +node.getFirstChild.getNodeValue; }
} note that at this point we are free to continue using evaluate
atLeast10 and totalItems against other documents }
}
5.2.3 Main Steps When Using the DOMXPath Class
