//**************************************************************************

//	Filename 	:	XmlFactory.java, WSSE Toolkit 2005

//

//	Author   	:	Denis Pilipchuk

//

//	Purpose  	:	Factory for XML-related functionality. Instantiates appropriate

//                  implementation of DocumentBuilder.

//

//	Disclaimer: This software is provided "as-is" and does not imply

//              any warranty or responsibility.

//****************************************************************************



package wsse.Toolkit.Utils.Xml;



import java.util.HashMap;



import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.ParserConfigurationException;



public class XmlFactory

{

	private static final String DBFProperty = "javax.xml.parsers.DocumentBuilderFactory";

	private static final String DefDBFImpl = "org.apache.xerces.jaxp.DocumentBuilderFactoryImpl";



	public XmlFactory()

	{

	}



	public XmlDocHelper GetDocHelper(String dbfImpl) throws XmlDocException

	{

		String key = null != dbfImpl ? dbfImpl : "";



        DocumentBuilder db = null;

        synchronized (m_docBuilders)

        {

            if (m_docBuilders.containsKey(key))

            {

                db = (DocumentBuilder)m_docBuilders.get(key);

            }

            else

            {

                // Create a new one for the requested implementation

                try

                {

                    db = CreateDocBuilder(dbfImpl);

                    m_docBuilders.put(key,db);

                }

                catch(ParserConfigurationException pce)

                {

                    throw new XmlDocException("Error creating document builder, impl: " + dbfImpl, pce);

                }

            }

        }



		return new XmlDocHelper(db);

	}



	private DocumentBuilder CreateDocBuilder(String dbfImpl) throws ParserConfigurationException

	{

		System.setProperty(XmlFactory.DBFProperty, null != dbfImpl && dbfImpl.length() > 0 ?

						   dbfImpl : XmlFactory.DefDBFImpl);

		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

		dbf.setNamespaceAware(true);

		return dbf.newDocumentBuilder();

	}



	private HashMap m_docBuilders = new HashMap();

}