/*
+----------------------------------------------------------------------+
|                    Class: CxmlParser                                 |
|                                                                      |
| Developper:  Eric Gavaldo (egavaldo@xqual.com)                       |
+----------------------------------------------------------------------+
*/
package com.xqual.xlauncher.testpartner;

//JAXP
import java.io.File;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;


/**
 * The <code>CXmlParser/code> class defines a XML parsing utility
 * @author egavaldo
 */
public class CXmlParser {

	// +==============================================================+
	// | Members                                                      |
	// +==============================================================+

	private static final String OUTPUT_ENCODING = "ISO-8859-1";

	private static final XPath xpath;
	
	private static DocumentBuilderFactory factory;
	private static TransformerFactory tFactory;
	private static DocumentBuilder builder;
	private static OutputStreamWriter errorWriter;

	// +==============================================================+
	// | Static Constructor                                           |
	// +==============================================================+

	static {
		factory = DocumentBuilderFactory.newInstance();
		tFactory = TransformerFactory.newInstance();

		try {
			builder = factory.newDocumentBuilder();
		} catch (ParserConfigurationException pce) {
			System.out.println("document builder: " + pce);
			System.exit(1);
		}

		// Set an ErrorHandler before parsing
		try {
			errorWriter = new OutputStreamWriter(System.err, OUTPUT_ENCODING);
		} catch (UnsupportedEncodingException uee) {
			System.out.println("OutputStreamWriter: " + uee);
			System.exit(1);
		}

		builder.setErrorHandler(new CErrorHandler(new PrintWriter(errorWriter, true)));

		xpath = XPathFactory.newInstance().newXPath();	
	}

	// +==============================================================+
	// | Methods                                                      |
	// +==============================================================+

	/**
	 * @param     xmlFile	File used as the source of the XML Doc
	 */
	public static Document createXMLDoc(File xmlFile) {
		Document xmlDocument = null;

		try {
			xmlDocument = builder.parse(xmlFile);
		} catch (SAXException se) {
			System.out.println("builder.parse: " + se.getMessage());
		} catch (IOException ioe) {
			System.out.println("builder.parse: " + ioe);
		}

		return xmlDocument;
	}

	/**
	 * @param     xmlString		XML string used as the source of the XML Doc
	 */
	public static Document createXMLDoc(String xmlString) {
		Document xmlDocument = null;

		try {
			StringReader stringReader = new StringReader(xmlString);
			InputSource inputSource = new InputSource(stringReader);
			xmlDocument = builder.parse(inputSource);
		} catch (SAXException se) {
			System.out.println("builder.parse: " + se.getMessage());
		} catch (IOException ioe) {
			System.out.println("builder.parse: " + ioe);
		} catch (Exception e) {
			System.out.println("builder.parse: " + e);
		} catch (Throwable t) {
			System.out.println("builder.parse: " + t);
		}

		return xmlDocument;
	}

	/**
	 * Get the documentElement of the xml document
	 */
	public static Element getDocumentElement(Document xmlDocument) {
		Element thisDocumentElement = xmlDocument.getDocumentElement();
		return thisDocumentElement;
	}

	/**
	 * Get a list of nodes based on a unique name
	 */
	public static NodeList getNodeObjList(
		Document xmlDocument,
		String nodeName) {
		NodeList thisNodeObjList = xmlDocument.getElementsByTagName(nodeName);
		return thisNodeObjList;
	}

	/**
	 * Get a single node based on its name
	 */
	public static Node getNodeObj(Document xmlDocument, String nodeName) {
		NodeList thisNodeObjList = getNodeObjList(xmlDocument, nodeName);
		Node thisNodeObj = null;

		if (thisNodeObjList.getLength() > 0) {
			thisNodeObj = thisNodeObjList.item(0);
		}

		return thisNodeObj;
	}

	/**
	 * Get a list of nodes based on a xPath
	 */
	public static NodeList getNodeObjListFromXPath(
		Document xmlDocument,
		String xPath) {
		NodeList thisNodeList = null;

		try {
			thisNodeList =  (NodeList)xpath.evaluate(xPath, xmlDocument, XPathConstants.NODESET);
		} catch (XPathExpressionException e) {
			System.out.println("evaluate " + xpath + ": " + e);					
		}

		return thisNodeList;
	}

	/**
	 * Get a list of nodes based on a xPath
	 */
	public static NodeList getNodeObjListFromXPath(Node node, String xPath) {
		NodeList thisNodeList = null;

		try {
			thisNodeList = (NodeList)xpath.evaluate(xPath, node, XPathConstants.NODESET);
		} catch (XPathExpressionException e) {
			System.out.println("evaluate " + xpath + ": " + e);
		}

		return thisNodeList;
	}

	/**
	 * Get a single node based on a xPath
	 */
	public static Node getNodeObjFromXPath(
		Document xmlDocument,
		String xPath) {
		Node thisNode = null;

		try {
			thisNode = (Node)xpath.evaluate(xPath, xmlDocument, XPathConstants.NODE);
		} catch (XPathExpressionException e) {
			System.out.println("evaluate " + xpath + ": " + e);
		}

		return thisNode;
	}

	/**
	 * Get a single node based on a xPath
	 */
	public static Node getNodeObjFromXPath(Node node, String xPath) {
		Node thisNode = null;

		try {
			thisNode = (Node)xpath.evaluate(xPath, node, XPathConstants.NODE);
		} catch (XPathExpressionException e) {
			System.out.println("evaluate " + xpath + ": " + e);
		}

		return thisNode;
	}

	/**
	 * Get a single node content based on its name
	 */
	public static String getNodeValue(Document xmlDocument, String nodeName) {
		Node thisNodeObj = getNodeObj(xmlDocument, nodeName);
		String thisNodeValue = null;

		if (thisNodeObj != null) {
			thisNodeValue = thisNodeObj.getFirstChild().getNodeValue();
		}

		return thisNodeValue;
	}

	/**
	 * Get a single node content based on a xPath
	 */
	public static String getNodeValueFromXPath(Document xmlDocument, String xPath) {
		Node thisNodeObj = getNodeObjFromXPath(xmlDocument, xPath);
		String thisNodeValue = null;

		if (thisNodeObj != null) {
			thisNodeValue = thisNodeObj.getFirstChild().getNodeValue();
		}

		return thisNodeValue;
	}

	/**
	 * Get a single node content based on a xPath
	 */
	public static String getNodeValueFromXPath(Node node, String xPath) {
		Node thisNodeObj = getNodeObjFromXPath(node, xPath);
		String thisNodeValue = null;

		if (thisNodeObj != null) {
			thisNodeValue = thisNodeObj.getFirstChild().getNodeValue();
		}

		return thisNodeValue;
	}

	/*
	+----------------------------------------------------------------------+
	|                    Class: CErrorHandler                              |
	+----------------------------------------------------------------------+
	*/

	/**
	 * A class representing an <b>Error Handler</b> for XML Parsing
	 */
	private static class CErrorHandler implements ErrorHandler {

		// +==============================================================+
		// | Members                                                      |
		// +==============================================================+

		private PrintWriter out;

		// +==============================================================+
		// | Constructors                                                 |
		// +==============================================================+

		CErrorHandler(PrintWriter out) {
			this.out = out;
		}

		// +==============================================================+
		// | Methods                                                      |
		// +==============================================================+

		private String getParseExceptionInfo(SAXParseException spe) {
			String systemId = spe.getSystemId();

			if (systemId == null) {
				systemId = "null";
			}

			String info = "URI=" + systemId + " Line=" + spe.getLineNumber() + ": " + spe.getMessage();
			return info;
		}

		public void warning(SAXParseException spe) throws SAXException {
			out.println("Warning: " + getParseExceptionInfo(spe));
		}

		public void error(SAXParseException spe) throws SAXException {
			String message = "Error: " + getParseExceptionInfo(spe);
			throw new SAXException(message);
		}

		public void fatalError(SAXParseException spe) throws SAXException {
			String message = "Fatal Error: " + getParseExceptionInfo(spe);
			throw new SAXException(message);
		}
	}

}