1 /* 2 * Copyright (C) 2007 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.eventbus; 18 19 import com.google.common.annotations.Beta; 20 21 /** 22 * Wraps an event that was posted, but which had no subscribers and thus could 23 * not be delivered. 24 * 25 * <p>Subscribing a DeadEvent handler is useful for debugging or logging, as it 26 * can detect misconfigurations in a system's event distribution. 27 * 28 * @author Cliff Biffle 29 * @since 10.0 30 */ 31 @Beta 32 public class DeadEvent { 33 34 private final Object source; 35 private final Object event; 36 37 /** 38 * Creates a new DeadEvent. 39 * 40 * @param source object broadcasting the DeadEvent (generally the 41 * {@link EventBus}). 42 * @param event the event that could not be delivered. 43 */ DeadEvent(Object source, Object event)44 public DeadEvent(Object source, Object event) { 45 this.source = source; 46 this.event = event; 47 } 48 49 /** 50 * Returns the object that originated this event (<em>not</em> the object that 51 * originated the wrapped event). This is generally an {@link EventBus}. 52 * 53 * @return the source of this event. 54 */ getSource()55 public Object getSource() { 56 return source; 57 } 58 59 /** 60 * Returns the wrapped, 'dead' event, which the system was unable to deliver 61 * to any registered handler. 62 * 63 * @return the 'dead' event that could not be delivered. 64 */ getEvent()65 public Object getEvent() { 66 return event; 67 } 68 69 } 70