/* 
 * Copyright (c) 2008 Stiftung Deutsches Elektronen-Synchrotron, 
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS. 
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND 
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE 
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR 
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. 
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION, 
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS 
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY 
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */
 package org.csstudio.sds.ui.widgetactionhandler;

import java.util.HashMap;
import java.util.Map;

import org.csstudio.sds.model.AbstractWidgetModel;
import org.csstudio.sds.model.ActionType;
import org.csstudio.sds.model.properties.actions.AbstractWidgetActionModel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The service performs the action depending on the given {@link ActionType}. 
 * @author Kai Meyer
 *
 */
public final class WidgetActionHandlerService {
	
    private static final Logger LOG = LoggerFactory.getLogger(WidgetActionHandlerService.class);

	/**
	 * The instance of the service.
	 */
	private static WidgetActionHandlerService _instance;
	/**
	 * The map of known {@link IWidgetActionHandler}.
	 */
	private Map<ActionType, IWidgetActionHandler> _handler;
	
	/**
	 * Constructor.
	 */
	private WidgetActionHandlerService() {
		initHandlers();
	}
	
	/**
	 * Creates and registers {@link IWidgetActionHandler}.
	 */
	private void initHandlers() {
		_handler = new HashMap<ActionType, IWidgetActionHandler>();
		_handler.put(ActionType.OPEN_DISPLAY, new OpenDisplayActionHandler());
		_handler.put(ActionType.COMMIT_VALUE, new CommitValueActionHandler());
		_handler.put(ActionType.EXECUTE_SCRIPT, new ExecuteScriptActionHandler());
	}

	/**
	 * Returns the instance of the {@link WidgetActionHandlerService}.
	 * @return The instance.
	 */
	public static WidgetActionHandlerService getInstance() {
		if (_instance==null) {
			_instance = new WidgetActionHandlerService();
		}
		return _instance;
	}
	
	/**
	 * Performs the action depending on the given {@link ActionType}.
	 * @param widget The {@link AbstractWidgetModel}
	 * @param action The type of the action
	 */
	public void performAction(final AbstractWidgetModel widget, final AbstractWidgetActionModel action) {
		if (action.isEnabled() && _handler.containsKey(action.getType()))
			_handler.get(action.getType()).executeAction(widget, action);
		else
			this.doUnknownAction();
	}
	
	/**
	 * Performs the unspecified  action.
	 */
	private void doUnknownAction() {
		LOG.info("Unknown WidgetAction performed!");
	}

}