org.apache.flink.streaming.connectors.rabbitmq.RMQSink.java Source code

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Here is the source code for org.apache.flink.streaming.connectors.rabbitmq.RMQSink.java

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/**
 *
 * 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.flink.streaming.connectors.rabbitmq;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.flink.streaming.api.function.sink.SinkFunction;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public abstract class RMQSink<IN> implements SinkFunction<IN> {
    private static final long serialVersionUID = 1L;

    private static final Log LOG = LogFactory.getLog(RMQSink.class);

    private boolean sendAndClose = false;
    private boolean closeWithoutSend = false;

    private String QUEUE_NAME;
    private String HOST_NAME;
    private transient ConnectionFactory factory;
    private transient Connection connection;
    private transient Channel channel;
    private boolean initDone = false;

    public RMQSink(String HOST_NAME, String QUEUE_NAME) {
        this.HOST_NAME = HOST_NAME;
        this.QUEUE_NAME = QUEUE_NAME;
    }

    /**
     * Initializes the connection to RMQ.
     */
    public void initializeConnection() {
        factory = new ConnectionFactory();
        factory.setHost(HOST_NAME);
        try {
            connection = factory.newConnection();
            channel = connection.createChannel();

        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        initDone = true;
    }

    /**
     * Called when new data arrives to the sink, and forwards it to RMQ.
     * 
     * @param value
     *            The incoming data
     */
    @Override
    public void invoke(IN value) {
        if (!initDone) {
            initializeConnection();
        }

        try {
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            byte[] msg = serialize(value);
            if (!closeWithoutSend) {
                channel.basicPublish("", QUEUE_NAME, null, msg);
            }
        } catch (IOException e) {
            if (LOG.isErrorEnabled()) {
                LOG.error("Cannot send RMQ message " + QUEUE_NAME + " at " + HOST_NAME);
            }
        }

        if (sendAndClose) {
            closeChannel();
        }
    }

    /**
     * Serializes tuples into byte arrays.
     * 
     * @param value
     *            The tuple used for the serialization
     * @return The serialized byte array.
     */
    public abstract byte[] serialize(IN value);

    /**
     * Closes the connection.
     */
    private void closeChannel() {
        try {
            channel.close();
            connection.close();
        } catch (IOException e) {
            throw new RuntimeException("Error while closing RMQ connection with " + QUEUE_NAME + " at " + HOST_NAME,
                    e);
        }

    }

    /**
     * Closes the connection immediately and no further data will be sent.
     */
    public void closeWithoutSend() {
        closeChannel();
        closeWithoutSend = true;
    }

    /**
     * Closes the connection only when the next message is sent after this call.
     */
    public void sendAndClose() {
        sendAndClose = true;
    }

}