聊聊AbstractOMSProducer

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本文主要研究一下AbstractOMSProducer

AbstractOMSProducer

io/openmessaging/rocketmq/producer/AbstractOMSProducer.java

abstract class AbstractOMSProducer implements ServiceLifecycle, MessageFactory {
    final static Logger log = ClientLogger.getLog();
    final KeyValue properties;
    final DefaultMQProducer rocketmqProducer;
    private boolean started = false;
    final ClientConfig clientConfig;

    AbstractOMSProducer(final KeyValue properties) {
        this.properties = properties;
        this.rocketmqProducer = new DefaultMQProducer();
        this.clientConfig = BeanUtils.populate(properties, ClientConfig.class);

        String accessPoints = clientConfig.getOmsAccessPoints();
        if (accessPoints == null || accessPoints.isEmpty()) {
            throw new OMSRuntimeException("-1", "OMS AccessPoints is null or empty.");
        }
        this.rocketmqProducer.setNamesrvAddr(accessPoints.replace(',', ';'));
        this.rocketmqProducer.setProducerGroup(clientConfig.getRmqProducerGroup());

        String producerId = buildInstanceName();
        this.rocketmqProducer.setSendMsgTimeout(clientConfig.getOmsOperationTimeout());
        this.rocketmqProducer.setInstanceName(producerId);
        this.rocketmqProducer.setMaxMessageSize(1024 * 1024 * 4);
        properties.put(PropertyKeys.PRODUCER_ID, producerId);
    }

    @Override
    public synchronized void startup() {
        if (!started) {
            try {
                this.rocketmqProducer.start();
            } catch (MQClientException e) {
                throw new OMSRuntimeException("-1", e);
            }
        }
        this.started = true;
    }

    @Override
    public synchronized void shutdown() {
        if (this.started) {
            this.rocketmqProducer.shutdown();
        }
        this.started = false;
    }

    OMSRuntimeException checkProducerException(String topic, String msgId, Throwable e) {
        if (e instanceof MQClientException) {
            if (e.getCause() != null) {
                if (e.getCause() instanceof RemotingTimeoutException) {
                    return new OMSTimeOutException("-1", String.format("Send message to broker timeout, %dms, Topic=%s, msgId=%s",
                        this.rocketmqProducer.getSendMsgTimeout(), topic, msgId), e);
                } else if (e.getCause() instanceof MQBrokerException || e.getCause() instanceof RemotingConnectException) {
                    MQBrokerException brokerException = (MQBrokerException) e.getCause();
                    return new OMSRuntimeException("-1", String.format("Received a broker exception, Topic=%s, msgId=%s, %s",
                        topic, msgId, brokerException.getErrorMessage()), e);
                }
            }
            // Exception thrown by local.
            else {
                MQClientException clientException = (MQClientException) e;
                if (-1 == clientException.getResponseCode()) {
                    return new OMSRuntimeException("-1", String.format("Topic does not exist, Topic=%s, msgId=%s",
                        topic, msgId), e);
                } else if (ResponseCode.MESSAGE_ILLEGAL == clientException.getResponseCode()) {
                    return new OMSMessageFormatException("-1", String.format("A illegal message for RocketMQ, Topic=%s, msgId=%s",
                        topic, msgId), e);
                }
            }
        }
        return new OMSRuntimeException("-1", "Send message to RocketMQ broker failed.", e);
    }

    protected void checkMessageType(Message message) {
        if (!(message instanceof BytesMessage)) {
            throw new OMSNotSupportedException("-1", "Only BytesMessage is supported.");
        }
    }

    @Override
    public BytesMessage createBytesMessageToTopic(final String topic, final byte[] body) {
        BytesMessage bytesMessage = new BytesMessageImpl();
        bytesMessage.setBody(body);
        bytesMessage.headers().put(MessageHeader.TOPIC, topic);
        return bytesMessage;
    }

    @Override
    public BytesMessage createBytesMessageToQueue(final String queue, final byte[] body) {
        BytesMessage bytesMessage = new BytesMessageImpl();
        bytesMessage.setBody(body);
        bytesMessage.headers().put(MessageHeader.QUEUE, queue);
        return bytesMessage;
    }
}

• AbstractOMSProducer实现了ServiceLifecycle以及MessageFactory
• ServiceLifecycle的startup里头调用DefaultMQProducer的start方法，shutdown里头调用DefaultMQProducer的shutdown方法
• MessageFactory的createBytesMessage的方法主要是返回了BytesMessageImpl

MessageFactory

io/openmessaging/openmessaging-api/0.1.0-alpha/openmessaging-api-0.1.0-alpha-sources.jar!/io/openmessaging/MessageFactory.java

/**
 * A factory interface for creating {@code Message} objects.
 *
 * @author vintagewang@apache.org
 * @author yukon@apache.org
 */
public interface MessageFactory {
    /**
     * Creates a {@code BytesMessage} object. A {@code BytesMessage} object is used to send a message containing a
     * stream of uninterpreted bytes.
     * <p>
     * The returned {@code BytesMessage} object only can be sent to the specified topic.
     *
     * @param topic the target topic to send
     * @param body the body data for a message
     * @return the created {@code BytesMessage} object
     * @throws OMSRuntimeException if the OMS provider fails to create this message due to some internal error.
     */
    BytesMessage createBytesMessageToTopic(String topic, byte[] body);

    /**
     * Creates a {@code BytesMessage} object. A {@code BytesMessage} object is used to send a message containing a
     * stream of uninterpreted bytes.
     * <p>
     * The returned {@code BytesMessage} object only can be sent to the specified queue.
     *
     * @param queue the target queue to send
     * @param body the body data for a message
     * @return the created {@code BytesMessage} object
     * @throws OMSRuntimeException if the OMS provider fails to create this message due to some internal error.
     */
    BytesMessage createBytesMessageToQueue(String queue, byte[] body);
}

• 0.1.0-alpha这个版本区分了topic跟queue，不过在最新版已经移除掉topic，统一为createBytesMessage方法，发送到queue

openmessaging-java/openmessaging-api/src/main/java/io/openmessaging/MessageFactory.java

public interface MessageFactory {
    /**
     * Creates a {@code BytesMessage} object. A {@code BytesMessage} object is used to send a message containing a
     * stream of uninterpreted bytes.
     * <p>
     * The returned {@code BytesMessage} object only can be sent to the specified queue.
     *
     * @param queue the target queue to send
     * @param body the body data for a message
     * @return the created {@code BytesMessage} object
     * @throws OMSRuntimeException if the OMS provider fails to create this message due to some internal error.
     */
    BytesMessage createBytesMessage(String queue, byte[] body);
}

BytesMessageImpl

io/openmessaging/rocketmq/domain/BytesMessageImpl.java

public class BytesMessageImpl implements BytesMessage {
    private KeyValue headers;
    private KeyValue properties;
    private byte[] body;

    public BytesMessageImpl() {
        this.headers = OMS.newKeyValue();
        this.properties = OMS.newKeyValue();
    }

    @Override
    public byte[] getBody() {
        return body;
    }

    @Override
    public BytesMessage setBody(final byte[] body) {
        this.body = body;
        return this;
    }

    @Override
    public KeyValue headers() {
        return headers;
    }

    @Override
    public KeyValue properties() {
        return properties;
    }

    @Override
    public Message putHeaders(final String key, final int value) {
        headers.put(key, value);
        return this;
    }

    @Override
    public Message putHeaders(final String key, final long value) {
        headers.put(key, value);
        return this;
    }

    @Override
    public Message putHeaders(final String key, final double value) {
        headers.put(key, value);
        return this;
    }

    @Override
    public Message putHeaders(final String key, final String value) {
        headers.put(key, value);
        return this;
    }

    @Override
    public Message putProperties(final String key, final int value) {
        properties.put(key, value);
        return this;
    }

    @Override
    public Message putProperties(final String key, final long value) {
        properties.put(key, value);
        return this;
    }

    @Override
    public Message putProperties(final String key, final double value) {
        properties.put(key, value);
        return this;
    }

    @Override
    public Message putProperties(final String key, final String value) {
        properties.put(key, value);
        return this;
    }

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this);
    }
}

• 用byte[]作为body实现BytesMessage接口

小结

rocketmq的4.2.0版本的AbstractOMSProducer实现了ServiceLifecycle以及MessageFactory，其实现的open-messaging api的版本为0.1.0-alpha，该版本的MessageFactory里头创建message的方法区分了topic和queue，而在最新的0.3.2-alpha-SNAPSHOT版本，已经移除了topic的概念，统一发送到queue。

doc

• AbstractOMSProducer

来源：oschina

链接：https://my.oschina.net/u/2922256/blog/1864944