import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.Namespace;
import org.jdom.input.SAXBuilder;
import org.jdom.output.XMLOutputter;
import org.xml.sax.EntityResolver;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

/**
 * @author Per Norrman
 *
 */
public class FragmentParser {

	private String _xml;

	private SAXBuilder _builder;

	private String _fragment = null;

	public FragmentParser(Namespace[] namespaces) {
		StringBuffer buf = new StringBuffer();
		buf.append(
			"<!DOCTYPE root [<!ENTITY fragment  SYSTEM 'file:fragment.xml' >]><root ");
		for (int i = 0; i < namespaces.length; i++) {
			buf.append("xmlns:");
			buf.append(namespaces[i].getPrefix());
			buf.append("=\"");
			buf.append(namespaces[i].getURI());
			buf.append("\" ");
		}
		buf.append(">&fragment;</root>");
		_xml = buf.toString();

		_builder = new SAXBuilder();
		_builder.setEntityResolver(new EntityResolver() {
			public InputSource resolveEntity(String publicId, String systemId)
				throws SAXException, IOException {
				if (_fragment != null) {
					return new InputSource(new StringReader(_fragment));
				} else {
					return null;
				}
			}

		});
	}

	public List parseFragment(String fragment) throws Exception {

		try {
			_fragment = fragment;
			Document doc = _builder.build(new StringReader(_xml));
			ArrayList list = new ArrayList(doc.getRootElement().getChildren());
			for (Iterator i = list.iterator(); i.hasNext();) {
				((Element)i.next()).detach();
			}
			_fragment = null;
			return list;
		} catch (Exception e) {
			throw e;
		} finally {
			_fragment = null;
		}
	}

	public static void main(String[] args) throws Exception, Exception {
		String[] testFragments =
			{ "<erm:xyz><abc/></erm:xyz>", "<stuff><p:test/></stuff>" };

		Namespace[] nslist =
			new Namespace[] {
				Namespace.getNamespace("erm", "xyz:abc"),
				Namespace.getNamespace("p", "xyz:def")};

		FragmentParser fp = new FragmentParser(nslist);

		for (int i = 0; i < testFragments.length; i++) {
			Document doc = new Document(new Element("new"));
			System.out.println("--> " + testFragments[i]);
			List l = fp.parseFragment(testFragments[i]);
			for (Iterator iter = l.iterator(); iter.hasNext();) {
				Element e = (Element)iter.next();
				doc.getRootElement().addContent(e);
			}
			XMLOutputter out = new XMLOutputter();
			out.output(doc, System.out);
		}

	}
}