cacheConfig.xml中读取配置文件信息一2010-07-07

package com.huawei.support.cache.impl;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
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.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

/**
* 从cacheConfig.xml中读取配置文件.
*/
public final class CacheConfigReader
{
/**
* sLog
*/
private static Log sLog = LogFactory.getLog(CacheConfigReader.class);
/**
* 本实例
*/
private static CacheConfigReader sInstance;
/**
* 最终修改时间
*/
private static long sLastModified = -1;
/**
* 缓存服务器列表
*/
private static String[] sServerList;
/**
* 默认Keyspace
*/
private static String sDefaultKeyspace;
/**
* 默认ColumnFamily
*/
private static String sDefaultColumnFamily;
/**
* DataBinding Map
*/
private static Map<String, String> sDataBindingMap =
new HashMap<String, String>();

/** 默认构造函数.
* @param aConfigFile 配置文件名
*/
private CacheConfigReader(String aConfigFile)
{
try
{
DocumentBuilderFactory factory =
DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(aConfigFile);
XPathFactory pathFactory = XPathFactory.newInstance();
XPath xpath = pathFactory.newXPath();
// 解析缓存服务器列表.
sServerList = readServerList(xpath, doc);
// 解析默认Keyspace.
sDefaultKeyspace = readDefaultKeyspace(xpath, doc);
// 解析默认ColumnFamily
sDefaultColumnFamily = readDefaultColumnFamily(xpath, doc);
// 解析DataBindings.
sDataBindingMap = readDataBindingMap(xpath, doc);
}
catch (ParserConfigurationException e)
{
sLog.error(e);
}
catch (XPathExpressionException e)
{
sLog.error(e);
}
catch (IOException e)
{
sLog.error(e);
}
catch (SAXException e)
{
sLog.error(e);
}
}