connectors/rabbitmq/src/main/java/org/apache/edgent/connectors/rabbitmq/RabbitmqProducer.java

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package org.apache.edgent.connectors.rabbitmq;

import org.apache.edgent.connectors.rabbitmq.runtime.RabbitmqConnector;
import org.apache.edgent.connectors.rabbitmq.runtime.RabbitmqPublisher;
import org.apache.edgent.function.Function;
import org.apache.edgent.function.Supplier;
import org.apache.edgent.topology.TSink;
import org.apache.edgent.topology.TStream;
import org.apache.edgent.topology.Topology;

import java.util.Map;

/**
 * {@code RabbitmqProducer} is a producer to produce messages to a RabbitMQ messaging broker
 * <p>
 * The connector uses and includes components from the RabbitMQ 3.7.3 release.
 * It has been successfully tested against 3.7.3.
 * For more information about RabbitMQ see <a href="http://www.rabbitmq.com/">http://www.rabbitmq.com/</a>
 * </p>
 * Sample use:
 * <pre>{@code
 * Map<String, Object> config = new HashMap<>();
 * config.put(RabbitmqConfigKeyConstants.RABBITMQ_CONFIG_KEY_HOST, "127.0.0.1");
 * config.put(RabbitmqConfigKeyConstants.RABBITMQ_CONFIG_KEY_PORT, 5672);
 * String queue = "testQueue";
 *
 * Topology t = newTopology("testSimple");
 * RabbitmqProducer producer = new RabbitmqProducer(t, () -> config);
 *
 * //TStream<String> stream = ...
 *
 * TSink<String> sink = producer.publish(stream, queue, (String s) -> s.getBytes());
 * }
 * </pre>
 */
public class RabbitmqProducer {

    private final RabbitmqConnector connector;
    private final Topology topology;

    /**
     * Create a producer connector for publishing tuples to a RabbitMQ queue.
     * <p>
     * See the RabbitMQ java client document :
     * <a href="http://www.rabbitmq.com/api-guide.html">http://www.rabbitmq.com/api-guide.html</a>
     * The full config option please see RabbitMQ java client API Reference :
     * < a href="https://rabbitmq.github.io/rabbitmq-java-client/api/current/com/rabbitmq/client/ConnectionFactory.html">ConnectionFactory</>
     * </p>
     * @param topology org.apache.edgent.org.apache.edgent.topology to add to
     * @param config RabbitmqProducer configuration information.
     */
    public RabbitmqProducer(Topology topology, Supplier<Map<String, Object>> config) {
        this.topology = topology;
        this.connector = new RabbitmqConnector(config);
    }

    /**
     * Publish the stream of tuples to the specified queue.
     * @param stream The stream to publish
     * @param queue The specified queue of RabbitMQ
     * @param msgFn A function that yields the byte[] records from the tuple
     * @param <T> Tuple type
     * @return {@link TSink}
     */
    public <T> TSink<T> publish(TStream<T> stream, String queue, Function<T, byte[]> msgFn) {
        return stream.sink(new RabbitmqPublisher<>(connector, queue, msgFn));
    }

    /**
     * Publish the stream of tuples to the specified queue.
     * @param stream The stream to publish
     * @param queue The specified queue of RabbitMQ
     * @param msg The string message to publish
     * @return
     */
    public TSink<String> publish(TStream<String> stream, String queue, String msg) {
        return publish(stream, queue, (String m) -> msg.getBytes());
    }

}