Java/XML/NamespaceContext

implements NamespaceContext

   <source lang="java">

import java.io.FileReader; import java.util.Collections; import java.util.HashMap; import java.util.HashSet; import java.util.Iterator; import java.util.Map; import java.util.Set; import javax.xml.XMLConstants; import javax.xml.namespace.NamespaceContext; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathFactory; import org.xml.sax.InputSource; public class MainClass {

 public static void main(String[] args) throws Exception {
   XPathFactory factory = XPathFactory.newInstance();
   XPath xPath = factory.newXPath();
   SimpleNamespaceContext nsContext = new SimpleNamespaceContext();
   nsContext.addNamespace("s", "uri:test:schedule");
   xPath.setNamespaceContext(nsContext);
   String result = xPath.evaluate("/s:schedule/@name", new InputSource(
       new FileReader("t.xml")));
   System.out.println(result);
 }

} class SimpleNamespaceContext implements NamespaceContext {

 private Map<String, String> urisByPrefix = new HashMap<String, String>();
 private Map<String, Set> prefixesByURI = new HashMap<String, Set>();
 public SimpleNamespaceContext() {
   addNamespace(XMLConstants.XML_NS_PREFIX, XMLConstants.XML_NS_URI);
   addNamespace(XMLConstants.XMLNS_ATTRIBUTE, XMLConstants.XMLNS_ATTRIBUTE_NS_URI);
 }
 public synchronized void addNamespace(String prefix, String namespaceURI) {
   urisByPrefix.put(prefix, namespaceURI);
   if (prefixesByURI.containsKey(namespaceURI)) {
     (prefixesByURI.get(namespaceURI)).add(prefix);
   } else {
     Set<String> set = new HashSet<String>();
     set.add(prefix);
     prefixesByURI.put(namespaceURI, set);
   }
 }
 public String getNamespaceURI(String prefix) {
   if (prefix == null)
     throw new IllegalArgumentException("prefix cannot be null");
   if (urisByPrefix.containsKey(prefix))
     return (String) urisByPrefix.get(prefix);
   else
     return XMLConstants.NULL_NS_URI;
 }
 public String getPrefix(String namespaceURI) {
   return (String) getPrefixes(namespaceURI).next();
 }
 public Iterator getPrefixes(String namespaceURI) {
   if (namespaceURI == null)
     throw new IllegalArgumentException("namespaceURI cannot be null");
   if (prefixesByURI.containsKey(namespaceURI)) {
     return ((Set) prefixesByURI.get(namespaceURI)).iterator();
   } else {
     return Collections.EMPTY_SET.iterator();
   }
 }

}

</source>