src/main/java/org/apache/rocketmq/cloudevent/impl/RocketMQMessageWriter.java

/*
 * 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.rocketmq.cloudevent.impl;

import io.cloudevents.CloudEventData;
import io.cloudevents.SpecVersion;
import io.cloudevents.core.format.EventFormat;
import io.cloudevents.core.message.MessageWriter;
import io.cloudevents.rw.CloudEventContextWriter;
import io.cloudevents.rw.CloudEventRWException;
import io.cloudevents.rw.CloudEventWriter;
import org.apache.rocketmq.common.message.Message;


public final class RocketMQMessageWriter<R> implements MessageWriter<CloudEventWriter<Message>, Message>, CloudEventWriter<Message> {

    private Message message;


    public RocketMQMessageWriter(String topic) {
        message = new Message();
        message.setTopic(topic);
    }

    public RocketMQMessageWriter(String topic, String keys) {
        message = new Message();

        message.setTopic(topic);

        if (keys != null && keys.length() > 0) {
            message.setKeys(keys);
        }
    }

    public RocketMQMessageWriter(String topic, String keys, String tags) {
        message = new Message();

        message.setTopic(topic);

        if (tags != null && tags.length() > 0) {
            message.setTags(tags);
        }

        if (keys != null && keys.length() > 0) {
            message.setKeys(keys);
        }
    }


    @Override
    public CloudEventContextWriter withContextAttribute(String name, String value) throws CloudEventRWException {

        String propName = RocketMQHeaders.ATTRIBUTES_TO_HEADERS.get(name);
        if (propName == null) {
            propName = RocketMQHeaders.CE_PREFIX + name;
        }
        message.putUserProperty(propName, value);
        return this;
    }

    @Override
    public RocketMQMessageWriter<R> create(final SpecVersion version) {
        message.putUserProperty(RocketMQHeaders.SPEC_VERSION, version.toString());
        return this;
    }

    @Override
    public Message setEvent(final EventFormat format, final byte[] value) throws CloudEventRWException {
        message.putUserProperty(RocketMQHeaders.CONTENT_TYPE, format.serializedContentType());
        message.setBody(value);
        return message;
    }

    @Override
    public Message end(final CloudEventData data) throws CloudEventRWException {
        message.setBody(data.toBytes());
        return message;
    }

    @Override
    public Message end() {
        message.setBody(null);
        return message;
    }
}