001/* 002 * GWTEventService 003 * Copyright (c) 2011 and beyond, strawbill UG (haftungsbeschr?nkt) 004 * 005 * This is free software; you can redistribute it and/or modify it 006 * under the terms of the GNU Lesser General Public License as 007 * published by the Free Software Foundation; either version 3 of 008 * the License, or (at your option) any later version. 009 * Other licensing for GWTEventService may also be possible on request. 010 * Please view the license.txt of the project for more information. 011 * 012 * This software is distributed in the hope that it will be useful, 013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 * Lesser General Public License for more details. 016 * 017 * You should have received a copy of the GNU Lesser General Public 018 * License along with this software; if not, write to the Free 019 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 020 * 02110-1301 USA, or see the FSF site: http://www.fsf.org. 021 */ 022package de.novanic.eventservice.client.event.filter; 023 024/** 025 * A CascadingEventFilter is based on cascading filter sequences. An CascadingEventFilter can only hold one next 026 * EventFilter. When the next EventFilter is also a CascadingEventFilter, it can handle another EventFilter... 027 * That technique can be used to build filter sequences (cascading). 028 * A other solution to build filter sequences is available with {@link de.novanic.eventservice.client.event.filter.CompositeEventFilter} 029 * or rather {@link de.novanic.eventservice.client.event.filter.EventFilterFactory#connect(EventFilter...)}. 030 * 031 * @author sstrohschein 032 * <br>Date: 05.03.2009 033 * <br>Time: 12:04:03 034 */ 035public interface CascadingEventFilter extends AppendableEventFilter 036{ 037 /** 038 * Returns the attached EventFilter. A CascadingEventFilter can only hold one {@link de.novanic.eventservice.client.event.filter.EventFilter}. 039 * EventFilter instances can be attached with {@link de.novanic.eventservice.client.event.filter.AppendableEventFilter#attach(EventFilter)}. 040 * @return the attached {@link de.novanic.eventservice.client.event.filter.EventFilter} 041 */ 042 EventFilter getAttachedEventFilter(); 043 044 /** 045 * Detaches the attached {@link de.novanic.eventservice.client.event.filter.EventFilter}. A CascadingEventFilter can 046 * only hold one {@link de.novanic.eventservice.client.event.filter.EventFilter}. 047 * EventFilter instances can be attached with {@link de.novanic.eventservice.client.event.filter.AppendableEventFilter#attach(EventFilter)}. 048 * @return true if an EventFilter was registered, otherwise false 049 */ 050 boolean detach(); 051}