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/*
* ============LICENSE_START=======================================================
* ONAP
* ================================================================================
* Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* 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.
* ============LICENSE_END=========================================================
*/
package org.onap.policy.common.endpoints.listeners;
import org.onap.policy.common.endpoints.event.comm.Topic.CommInfrastructure;
import org.onap.policy.common.utils.coder.Coder;
import org.onap.policy.common.utils.coder.CoderException;
import org.onap.policy.common.utils.coder.StandardCoder;
import org.onap.policy.common.utils.coder.StandardCoderObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Listens for receipt of a {@link StandardCoderObject}, translating it into an object of
* the appropriate type, and then passing it to the subclass.
*
* @param <T> type of message/POJO this handles
*/
public abstract class ScoListener<T> {
private static final Logger logger = LoggerFactory.getLogger(ScoListener.class);
/**
* Used to translate the standard object to an object of type "T".
*/
private static final Coder coder = new StandardCoder();
/**
* Class of message this handles.
*/
private final Class<T> clazz;
/**
* Constructs the object.
*
* @param clazz class of message this handles
*/
public ScoListener(Class<T> clazz) {
this.clazz = clazz;
}
/**
* Receives an event, translates it into the desired type of object, and passes it to
* the subclass.
*
* @param infra infrastructure with which the message was received
* @param topic topic on which the message was received
* @param sco event that was received
*/
public void onTopicEvent(CommInfrastructure infra, String topic, StandardCoderObject sco) {
// translate the event to the desired object type
final T msg;
try {
msg = coder.fromStandard(sco, clazz);
} catch (CoderException e) {
logger.warn("unable to decode {}: {}", clazz.getName(), sco, e);
return;
}
onTopicEvent(infra, topic, sco, msg);
}
/**
* Indicates that a message was received.
*
* @param infra infrastructure with which the message was received
* @param topic topic on which the message was received
* @param sco event that was received
* @param message message that was received
*/
public abstract void onTopicEvent(CommInfrastructure infra, String topic, StandardCoderObject sco, T message);
}
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