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;
import com.google.common.base.MoreObjects;
/**
* 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
*/
@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
* subscriber.
*
* @return the 'dead' event that could not be delivered.
*/
public Object getEvent() {
return event;
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this).add("source", source).add("event", event).toString();
}
}