package com.amarsoft.aims.util;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
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.SAXException;

import com.amarsoft.are.ARE;
import com.amarsoft.are.log.Log;

/**
 * 使用XPath的XML对象
 * @author yangsong
 * @date 2013/11/11
 */
public class XMLParse{
	public static final String DEFAULT_CHARSET = "GBK";
	private Log log = null;
	private Document document;
	
	public XMLParse(){
		this(ARE.getLog());
	}
	public XMLParse(Log log){
		setLog(log);
	}
	public void setLog(Log log){
		log = ARE.getLog();
	}
	/**
	 * 构造函数
	 * @param file
	 * @param xPathExpr
	 */
	public XMLParse(File file) {
		this();
		// 1.得到DOM解析器的工厂实例
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		try {
			DocumentBuilder builder = factory.newDocumentBuilder();
			document = builder.parse(file);
		} catch (SAXException e) {
			log.error("SAXException",e);
		} catch (IOException e) {
			log.error("IOException",e);
		} catch (ParserConfigurationException e) {
			log.error("ParserConfigurationException",e);
		}
	}
	/**
	 * 构造函数
	 * @param file
	 * @param xPathExpr
	 */
	public XMLParse(InputStream in) {
		this();
		// 1.得到DOM解析器的工厂实例
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		try {
			DocumentBuilder builder = factory.newDocumentBuilder();
			document = builder.parse(in);
		} catch (SAXException e) {
			log.error("SAXException",e);
		} catch (IOException e) {
			log.error("IOException",e);
		} catch (ParserConfigurationException e) {
			log.error("ParserConfigurationException",e);
		}
	}
	/**
	 * 使用XML字串构建一个对象
	 * @param xmlString
	 */
	public XMLParse(String xmlString){
		this();
		// 1.得到DOM解析器的工厂实例
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		try {
			DocumentBuilder builder = factory.newDocumentBuilder();
			InputStream inputStream = new ByteArrayInputStream(xmlString.getBytes());//xml为要解析的字符串
			document = builder.parse(inputStream);
		} catch (SAXException e) {
			log.error("SAXException",e);
		} catch (IOException e) {
			log.error("IOException",e);
		} catch (ParserConfigurationException e) {
			log.error("ParserConfigurationException",e);
		}			
	}
	/**
	 * 根据XPath表达式，取节点列表
	 * @param xPathExpr
	 * @return
	 */
	public NodeList getNodeList(String xPathExpr){
		NodeList nodeList = null;
		try {
			XPathFactory xFactory = XPathFactory.newInstance();
			XPath xPath = xFactory.newXPath(); 
			XPathExpression xExpr = xPath.compile(xPathExpr);
			nodeList = (NodeList)xExpr.evaluate(document,XPathConstants.NODESET);    
		} catch (XPathExpressionException e) {
			log.error("XPathExpressionException",e);
		}			
		return nodeList;
	}
	/**
	 * 根据XPath表达式，取一个节点，如有多个，则返回第一个
	 * @param xPathExpr
	 * @return
	 */
	public Node getNode(String xPathExpr){
		NodeList nodeList = getNodeList(xPathExpr);
		if(nodeList.getLength()>0){
			return nodeList.item(0);
		}else{
			return null;
		}
	}
	/**
	 * 根据XPath表达式，取一个节点，如有多个，则返回第一个
	 * @param xPathExpr
	 * @return
	 */
	public Element getElement(String xPathExpr){
		return (Element)getNode(xPathExpr);
	}
	/**
	 * 获取一个XML片段
	 * @param xPathExpr
	 * @param charset
	 * @return
	 */
	public String getXMLString(String xPathExpr, String charset) {
		String xmlString = null;
		Node node = getNode(xPathExpr);
		if(node==null)return xmlString;
		try {
			TransformerFactory factory = TransformerFactory.newInstance();
			Transformer transformer;
			transformer = factory.newTransformer();
			DOMSource source = new DOMSource(node);
			transformer.setOutputProperty(OutputKeys.ENCODING, charset);
			transformer.setOutputProperty(OutputKeys.INDENT, "yes");
			StringWriter writer = new StringWriter();
			StreamResult result = new StreamResult(writer);
			transformer.transform(source, result);
			xmlString = writer.toString();
		} catch (TransformerConfigurationException e) {
			log.error("TransformerConfigurationException", e);
		} catch (TransformerException e) {
			log.error("TransformerException", e);
		}
		return xmlString;
	}
	/**
	 * 取一个XML片段，默认使用UTF-8
	 * @param xPathExpr
	 * @return
	 */
	public String getXMLString(String xPathExpr){
		return getXMLString(xPathExpr,DEFAULT_CHARSET);
	}
	/**
	 * 返回文档对象
	 * @return
	 */
	public Document getDocument(){
		return this.document;
	}
}