/*
 * Copyright (c) 2006 Stiftung Deutsches Elektronen-Synchroton,
 * 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.dal;

import java.util.Map;


/**
 * This is context for generic events generated by event system.
 *
 * @author Igor Kriznar (igor.kriznarATcosylab.com)
 */
public interface EventSystemContext<E extends SystemEvent<?,?>>
{
	/**
	 * Registers general listener for events from EventSystem.
	 * Paramaters in map provide information under which events and under
	 * which condition listner wants to receive events from EventSystm. This
	 * is generic apporach, at the moment parameters are not specified.<p>Same
	 * listner instance can be registered under everal different events
	 * defined with parameters. To unregister listener, it must be
	 * unregistered with same parameters as registered.</p>
	 *
	 * @param parameters the paramaters for EventSystem
	 * @param l EventSystem listener
	 *
	 * @throws RemoteException if creation with remote system fails
	 */
	public void addEventSystemListener(EventSystemListener<E> l,
	    Map<String, Object> parameters) throws RemoteException;

	/**
	 * Registers general listener for all events from EventSystem.
	 *
	 * @param l EventSystem listener
	 *
	 * @throws RemoteException if creation with remote system fails
	 */
	public void addEventSystemListener(EventSystemListener<E> l)
		throws RemoteException;

	/**
	 * Removes general listener for events from EventSystem. Paramaters
	 * in map must be same as when  listener was registered. If listener was
	 * registered several times with different parameters, than  for each
	 * registration listener must be unregisterd with same parameters as were
	 * use for registeration. If parameter are <code>null</code> than listener
	 * is unregistered from ALL events for which was registered  with differnt
	 * parameters.
	 *
	 * @param parameters the paramaters for EventSystem, if <code>null</code>
	 *        it is unregistered for ALL events
	 * @param l EventSystem listener
	 */
	public void removeEventSystemListener(EventSystemListener<E> l,
	    Map<String, Object> parameters);

	/**
	 * Removes general listener for all events from EventSystem.
	 *
	 * @param l EventSystem listener
	 */
	public void removeEventSystemListener(EventSystemListener<E> l);

	/**
	 * Returns array with all registered event system listeners. If listener is registered several times,
	 * only one instance is returned.
	 *
	 * @return array with all registered event system listeners
	 */
	public EventSystemListener<E>[] getEventSystemListeners();

	/**
	 * Returns map with supported parameters for event system listeners, may be <code>null</code>.
	 * Key value pairs may be in following combinations:
	 *
	 * <ul>
	 * <li>If key is defined and value is <code>null</code> it means that it is enough to provide
	 * key with <code>null</code> valeu in parameter in order to acctivate specific event parameter.</li>
	 * <li>If value is of tyle <code>Class</code>, this means that only values of specified type
	 * are supported for this key.</li>
	 * <li>If value is array, than only elements in array are supported as parameters for this key.</li>
	 * <li>If value is Java 1.5 enum class, than only enum elements are supported as parameters
	 * for this key.</li>
	 * </ul>
	 *
	 * <p>If returned map is <code>null</code> or empty, than no special parameters are supported
	 * and they have no efect.</p>
	 *
	 * @return map with supported parameters.
	 */
	public Map<String, Object> getSupportedEventSystemParameters();
}

/* __oOo__ */