BaseConfigManager.java

/*******************************************************************************
 *     Copyright (c) 2006-2010 eBay Inc. All Rights Reserved.
 *     Licensed under the Apache License, Version 2.0 (the "License"); 
 *     you may not use this file except in compliance with the License. 
 *     You may obtain a copy of the License at 
 *    
 *        http://www.apache.org/licenses/LICENSE-2.0
 *******************************************************************************/
package org.ebayopensource.turmeric.utils.config;

import org.ebayopensource.turmeric.utils.XMLParseUtils;
import org.ebayopensource.turmeric.utils.config.exceptions.ConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;


public abstract class BaseConfigManager { 
	protected static final String BASE_PATH = "META-INF/security/";
	protected static final String BASE_SCHEMA_PATH = "META-INF/security/schema/";
	protected static final String CONFIG_RELATIVE_PATH = "config";
	
	protected Element m_rootData = null;
	protected boolean m_configLoaded = false;
	protected String m_configRelativePath = CONFIG_RELATIVE_PATH;
	protected String m_configFullPath = BASE_PATH + CONFIG_RELATIVE_PATH + "/";
	protected String m_schemaPath = BASE_SCHEMA_PATH + CONFIG_RELATIVE_PATH + "/";
	
	public static final String SYS_PROP_CONFIG_LOCATION 
			= "com.ebay.securityframework.impl.config.location";
	protected static String s_system_config_location = null;
	
	static {
		// read from system property for the location of the config
		s_system_config_location = System.getProperty(SYS_PROP_CONFIG_LOCATION);
	}

	
	protected synchronized void init() throws ConfigurationException {
		loadConfig();
	}
	
	protected synchronized void loadConfig() throws ConfigurationException {
		if (m_configLoaded) {
			return;
		}
		// system config location takes precedence over the default ones
		if (s_system_config_location != null) {
			m_configFullPath = s_system_config_location;
		}
		String fullConfigFileName = m_configFullPath + getConfigFileName();
		String fullSchemaFileName = m_schemaPath + getSchemaFileName();
		loadConfigFromFile(fullConfigFileName, fullSchemaFileName, getRootElementName());
		m_configLoaded = true;
	}
	
	private synchronized void loadConfigFromFile(String fileName, String schemaName, String rootElementName) 
		throws ConfigurationException {
		if (m_rootData != null) {
			return;
		}
		// get the root element by parsing the specified filename
		m_rootData = getRootData(fileName, schemaName, rootElementName);

		// map the root element to corresponding user-friendly object
		map(m_rootData);
	}

	// get root element
	private Element getRootData(String fileName, String schemaName, String rootElementName) throws ConfigurationException {
		Document doc = null;
		try {
			doc = XMLParseUtils.parseXML(fileName, schemaName, true, rootElementName);
		} catch (Exception e) {
			throw new ConfigurationException(
					"Parse XML failed: " + e.getMessage(), 
					e);
		}
		if (doc != null) {
			return doc.getDocumentElement();
		} else {
			return null;
		}
	}
	
	public String getConfigPath() {
		return m_configFullPath;
	}
	
	private synchronized void setConfigPath(String path) {
		m_configFullPath = path;
	}

	public synchronized void setConfigTestCase(String relativePath, boolean force) {
		m_configRelativePath = relativePath;
		String newPath = BASE_PATH + relativePath + "/";
		if (!force && m_configFullPath != null && m_configFullPath.equals(newPath)) {
			return;
		}

		m_configLoaded = false;
		m_rootData = null;
		setConfigPath(newPath);

	}
	
	public void setConfigTestCase(String relativePath) {
		setConfigTestCase(relativePath, false);
	} 
	
	public String getConfigTestCase() {
		return m_configRelativePath;
	}

	/**
	 * Perform the mapping from DOM element to user-friendly config object
	 * @param rootData
	 */
	public abstract void map(Element rootData) throws ConfigurationException;

	/**
	 * Specify the config file name
	 * @return
	 */
	public abstract String getConfigFileName();

	/**
	 * Specify the schema file name
	 * @return
	 */
	public abstract String getSchemaFileName();

	/**
	 * Specify the root element name for the xml config instance. 
	 * Needed for XML instance validation purpose
	 * @return
	 */
	public abstract String getRootElementName();

}