org.killbill.commons.eventbus.DeadEvent Maven / Gradle / Ivy
/*
* Copyright (C) 2007 The Guava Authors
* Copyright 2020-2022 Equinix, Inc
* Copyright 2014-2022 The Billing Project, LLC
*
* The Billing Project licenses this file to you under the Apache License, version 2.0
* (the "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.killbill.commons.eventbus;
import org.killbill.commons.utils.Preconditions;
/**
* Wraps an event that was posted, but which had no subscribers and thus could not be delivered.
*
* Registering a DeadEvent subscriber is useful for debugging or logging, as it can detect
* misconfigurations in a system's event distribution.
*
* @author Cliff Biffle
* @since 10.0
*/
public class DeadEvent {
private final Object source;
private final Object event;
/**
* Creates a new DeadEvent.
*
* @param source object broadcasting the DeadEvent (generally the {@link EventBus}).
* @param event the event that could not be delivered.
*/
public DeadEvent(final Object source, final Object event) {
this.source = Preconditions.checkNotNull(source);
this.event = Preconditions.checkNotNull(event);
}
/**
* Returns the object that originated this event (not the object that originated the
* wrapped event). This is generally an {@link EventBus}.
*
* @return the source of this event.
*/
public Object getSource() {
return source;
}
/**
* Returns the wrapped, 'dead' event, which the system was unable to deliver to any registered
* subscriber.
*
* @return the 'dead' event that could not be delivered.
*/
public Object getEvent() {
return event;
}
@Override
public String toString() {
return "DeadEvent {" +
"source=" + source +
", event=" + event +
'}';
}
}