Config.java

/*
 * Copyright (c) 2012 EMC Corporation
 * All Rights Reserved
 */
package com.emc.storageos.vasa;

import java.io.IOException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPathExpressionException;

import org.apache.log4j.Logger;
import org.xml.sax.SAXException;

import com.emc.storageos.vasa.util.XmlParser;

public class Config {

    private static final Logger _log = Logger.getLogger(Config.class);

    private static Config _config;
    private XmlParser _configParser;

    private Config() {
        final String methodName = "Config(): ";
        final String CONFIG_FILE_PATH = System.getProperty("vasa.config");
        _configParser = new XmlParser();
        try {
            _log.debug(methodName + " loading config file: " + CONFIG_FILE_PATH);
            _configParser.loadFile(CONFIG_FILE_PATH);
        } catch (ParserConfigurationException e) {
            _log.error(methodName + "Unable to parse XML content ", e);
        } catch (SAXException e) {
            _log.error(methodName + "Unable to parse XML content ", e);
        } catch (IOException e) {
            _log.error(methodName + "Unable to load file: " + CONFIG_FILE_PATH, e);
        }
    }

    public static synchronized Config getInstance() {

        if (_config == null) {
            _config = new Config();
        }
        return _config;
    }

    public String getConfigValue(String configName) {

        final String methodName = "getConfigValue(): ";
        String value = null;

        try {
            value = _configParser.getString(configName, null);
        } catch (XPathExpressionException e) {
            _log.error(methodName + "Unable to resolve XPath: " + configName, e);
        }
        return value;
    }

}