Metacat

package edu.ucsb.nceas.metacat.plugin;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.Map.Entry;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import edu.ucsb.nceas.metacat.properties.PropertyService;

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

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

public class MetacatHandlerPluginManager {

	private static MetacatHandlerPluginManager instance = null;

	private static Log log = LogFactory.getLog(MetacatHandlerPluginManager.class);

	private List<MetacatHandlerPlugin> handlers= new ArrayList<MetacatHandlerPlugin>();

	private MetacatHandlerPluginManager() {

		String[] configuredHandlers = null;

		try {

			String handlersString = PropertyService.getProperty("plugin.handlers");

			if (handlersString != null && handlersString.length() > 0) {

				configuredHandlers = handlersString.split(",");

				for (String className: configuredHandlers) {

					MetacatHandlerPlugin handlerInstance = null;

					try {

						Class<?> handlerClass = Class.forName(className);

						handlerInstance = (MetacatHandlerPlugin) handlerClass.newInstance();

					} catch (Exception e) {

						log.error("Problem initializing MetacatHandlerPlugin: " + className, e);

						continue;

					}

					handlers.add(handlerInstance);

				}

			}

		} catch (PropertyNotFoundException e) {

			log.warn("Could not find any MetacatPluginHandlers", e);

			return;

		}

	}

	public static MetacatHandlerPluginManager getInstance() throws ServiceException {

		if (instance == null) {

			try {

				instance = new MetacatHandlerPluginManager();

			} catch (Exception e) {

				throw new ServiceException(e.getMessage());

			}

		}

		return instance;

	}

	public void addHandler(MetacatHandlerPlugin plugin) {

	}

	public MetacatHandlerPlugin getHandler(String action) {

		for (MetacatHandlerPlugin plugin: handlers) {

			if (plugin.handlesAction(action)) {

				return plugin;

			}

		}

		return null;

	}

}