apps/kafka-integration/core/src/main/java/org/onosproject/kafkaintegration/impl/KafkaPublisherManager.java

/**
 * Copyright 2016-present Open Networking Laboratory
 * 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 org.onosproject.kafkaintegration.impl;

import org.onosproject.event.AbstractListenerManager;
import org.onosproject.kafkaintegration.api.ExportableEventListener;
import org.onosproject.kafkaintegration.api.KafkaPublisherService;
import org.onosproject.kafkaintegration.api.dto.OnosEvent;
import org.onosproject.kafkaintegration.api.dto.OnosEvent.Type;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.protobuf.GeneratedMessageV3;

/**
 * Dispatch ONOS Events to all interested Listeners.
 *
 */

public final class KafkaPublisherManager
        extends AbstractListenerManager<OnosEvent, ExportableEventListener> implements KafkaPublisherService {

    private final Logger log = LoggerFactory.getLogger(getClass());

    // Exists to defeat instantiation
    private KafkaPublisherManager() {
    }

    //TODO: If possible, get rid of Singleton implementation.
    private static class SingletonHolder {
        private static final KafkaPublisherManager INSTANCE = new KafkaPublisherManager();
    }

    /**
     * Returns a static reference to the Listener Factory.
     *
     * @return singleton object
     */
    public static KafkaPublisherManager getInstance() {
        return SingletonHolder.INSTANCE;
    }

    @Override
    public void publish(Type eventType, GeneratedMessageV3 message) {
        log.debug("Dispatching ONOS Event {}", eventType);
        post(new OnosEvent(eventType, message));
    }
}