MainClass.java Source code

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Here is the source code for MainClass.java

Source

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();
        }
    }

}