Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that controls other services 

 *  Copyright: 2008 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Michael Daigle

 * 

 *   '$Author: daigle $'

 *     '$Date: 2008-10-09 09:53:18 -0700 (Thu, 09 Oct 2008) $'

 * '$Revision: 4429 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.service;

import javax.servlet.ServletContext;

import org.apache.log4j.Logger;

import java.util.Hashtable;

import java.util.Set;

import edu.ucsb.nceas.metacat.shared.BaseService;

import edu.ucsb.nceas.metacat.shared.ServiceException;

import edu.ucsb.nceas.metacat.util.SystemUtil;

public class ServiceService {

	private static ServiceService serviceService = null;

    private static final String CONFIG_DIR = "WEB-INF";

	private static String REAL_CONFIG_DIR = "";

	private static final String SKIN_DIR = "/style/skins";

	private static String REAL_SKIN_DIR = "";

	private static String REAL_APPLICATION_CONTEXT = null;

	private static Logger logMetacat = Logger.getLogger(ServiceService.class);

	private static Hashtable<String, BaseService> serviceList = new Hashtable<String, BaseService>();

	/**

	 * private constructor since this is a singleton

	 */

	private ServiceService(ServletContext servletContext) {

		REAL_CONFIG_DIR = servletContext.getRealPath(CONFIG_DIR);

		REAL_SKIN_DIR = servletContext.getRealPath(SKIN_DIR);

		REAL_APPLICATION_CONTEXT = SystemUtil.discoverApplicationContext(servletContext);

	}

	/**

	 * Get the single instance of ServiceService.

	 * 

	 * @return the single instance of ServiceService

	 */

	public static ServiceService getInstance(ServletContext servletContext) {

		if (serviceService == null) {

			serviceService = new ServiceService(servletContext);

		}

		return serviceService;

	}

	/**

	 * Register a service with the system.

	 * 

	 * @param serviceName

	 *            the name of the service

	 * @param service

	 *            the singleton instance of the service

	 */

	public static void registerService(String serviceName, BaseService service)

			throws ServiceException {

		if (serviceList.containsKey(serviceName)) {

			throw new ServiceException("ServiceService.registerService - Service: " + serviceName + " is already registered."

					+ " Use ServiceService.reregister() to replace the service.");

		}

		logMetacat.info("ServiceService.registerService - Registering Service: " + serviceName);

		serviceList.put(serviceName, service);

	}

	/**

	 * Refresh a service.

	 * 

	 * @param serviceName

	 *            the name of the service to refresh

	 */

	public static void refreshService(String serviceName)

			throws ServiceException {

		if (!serviceList.containsKey(serviceName)) {

			throw new ServiceException("ServiceService.refreshService - Service: " + serviceName + " is not registered.");

		}

		BaseService baseService = serviceList.get(serviceName);

		if (!baseService.refreshable()) {

			throw new ServiceException("ServiceService.refreshService - Service: " + serviceName + " is not refreshable.");

		}

		logMetacat.info("ServiceService.refreshService - Refreshing Service: " + serviceName);

		baseService.refresh();

	}

	public static void stopAllServices() {

		Set<String> keySet = serviceList.keySet();

		for (String key : keySet) {

			try {

				logMetacat.info("ServiceService- stopAllServices: Stopping Service: " + key);

				serviceList.get(key).stop();

			} catch (ServiceException se) {

				logMetacat.error("ServiceService.stopAllServices - problem starting service: " 

						+ key + " : " + se.getMessage());

			}

		}

	}

	/**

	 * Convert the relative config directory to a full path

	 * @return the full config path

	 */

	public static String getRealConfigDir() throws ServiceException {

		if (serviceService == null) {

			throw new ServiceException("ServiceService.getRealConfigDir - Cannot access config dir before Service has been initialized");

		}

		return REAL_CONFIG_DIR;

	}

	/**

	 * Convert the relative skins directory to a full path

	 * @return the full skins directory path

	 */

	public static String getRealSkinDir() throws ServiceException {

		if (serviceService == null) {

			throw new ServiceException("ServiceService.getRealSkinDir - Cannot access skin dir before Service has been initialized");

		}

		return REAL_SKIN_DIR;

	}

	/**

	 * Get the servlet context name

	 * @return a string holding the context name

	 */

	public static String getRealApplicationContext() throws ServiceException {

		if (REAL_APPLICATION_CONTEXT == null) {

			throw new ServiceException("ServiceService.getRealApplicationContext - Application context name is null");

		}

		return REAL_APPLICATION_CONTEXT;

	}

}