/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.apache.flink.runtime.io.network.api;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import org.apache.flink.runtime.event.TaskEvent;
import org.apache.flink.runtime.util.event.EventListener;
/**
* The event handler manages {@link EventListener} instances and allows to
* to publish events to them.
*/
public class TaskEventHandler {
/** Listeners for each event type */
private final Multimap<Class<? extends TaskEvent>, EventListener<TaskEvent>> listeners = HashMultimap.create();
public void subscribe(EventListener<TaskEvent> listener, Class<? extends TaskEvent> eventType) {
synchronized (listeners) {
listeners.put(eventType, listener);
}
}
public void unsubscribe(EventListener<TaskEvent> listener, Class<? extends TaskEvent> eventType) {
synchronized (listeners) {
listeners.remove(eventType, listener);
}
}
/**
* Publishes the task event to all subscribed event listeners.
*
* @param event The event to publish.
*/
public void publish(TaskEvent event) {
synchronized (listeners) {
for (EventListener<TaskEvent> listener : listeners.get(event.getClass())) {
listener.onEvent(event);
}
}
}
}