com.google.common.eventbus.DeadEvent Maven / Gradle / Ivy
/*
* Copyright (C) 2007 The Guava Authors
*
* Licensed 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 com.google.common.eventbus;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.Beta;
/**
* Wraps an event that was posted, but which had no subscribers and thus could
* not be delivered.
*
* Subscribing a DeadEvent handler is useful for debugging or logging, as it
* can detect misconfigurations in a system's event distribution.
*
* @author Cliff Biffle
* @since 10.0
*/
@Beta
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(Object source, Object event) {
this.source = checkNotNull(source);
this.event = 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 handler.
*
* @return the 'dead' event that could not be delivered.
*/
public Object getEvent() {
return event;
}
}