uk.trainwatch.rabbitmq.RabbitConnection.java Source code

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Here is the source code for uk.trainwatch.rabbitmq.RabbitConnection.java

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/*
 * Copyright 2015 peter.
 *
 * 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.
 */
package uk.trainwatch.rabbitmq;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.ShutdownSignalException;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeoutException;
import java.util.logging.Level;
import java.util.logging.Logger;
import uk.trainwatch.util.config.Configuration;

/**
 * A representation of a connection to RabbitMQ
 * <p>
 * @author Peter T Mount
 */
public class RabbitConnection {

    private static final Logger LOG = Logger.getLogger(RabbitConnection.class.getName());
    private final String username;
    private final String password;
    private final String virtualHost;
    private final String host;
    private final int portNumber;
    /**
     * The current connection
     */
    private Connection connection;
    /**
     * Map of currently open channels
     */
    private final Map<Object, Channel> channels = new ConcurrentHashMap<>();

    RabbitConnection() {
        this(System.getenv("RABBIT_USER"), System.getenv("RABBIT_PASSWORD"), System.getenv("RABBIT_HOST"),
                Integer.parseInt(Objects.toString(System.getenv("RABBIT_PORT"), "0")),
                Objects.toString(System.getenv("RABBIT_VHOST"), null));
    }

    public RabbitConnection(Configuration config) {
        this(config.getString("username"), config.getString("password"), config.getString("hostname"),
                config.getInt("port", 0), config.getString("vhost", () -> null));
    }

    /**
     *
     * @param username    remote username
     * @param password    remote password
     * @param host        remote server
     * @param portNumber  server port
     * @param virtualHost virtual host
     */
    public RabbitConnection(final String username, final String password, final String host, final int portNumber,
            String virtualHost) {
        this.username = Objects.requireNonNull(username);
        this.password = Objects.requireNonNull(password);
        this.virtualHost = virtualHost;
        this.host = Objects.requireNonNull(host);
        this.portNumber = portNumber;
    }

    /**
     *
     * @param username remote username
     * @param password remote password
     * @param host     remote server
     */
    public RabbitConnection(final String username, final String password, final String host) {
        this(username, password, host, 0, null);
    }

    /**
     *
     * @param username   remote username
     * @param password   remote password
     * @param host       remote server
     * @param portNumber server port
     */
    public RabbitConnection(final String username, final String password, final String host, final int portNumber) {
        this(username, password, host, portNumber, null);
    }

    /**
     *
     * @param username    remote username
     * @param password    remote password
     * @param host        remote server
     * @param virtualHost virtual host
     */
    public RabbitConnection(final String username, final String password, final String host, String virtualHost) {
        this(username, password, host, 0, virtualHost);
    }

    /**
     * Get the current connection, creating one as needed
     * <p>
     * @return <p>
     * @throws IOException
     */
    public synchronized Connection getConnection() throws IOException {
        if (connection == null) {
            createConnection();
        }
        return connection;
    }

    private void createConnection() throws IOException {
        if (connection != null) {
            close();
        }

        LOG.log(Level.FINE, "building connection");
        ConnectionFactory factory = new ConnectionFactory();
        factory.setUsername(username);
        factory.setPassword(password);
        if (virtualHost != null) {
            factory.setVirtualHost(virtualHost);
        }
        factory.setHost(host);
        if (portNumber > 0) {
            factory.setPort(portNumber);
        }

        channels.clear();

        LOG.log(Level.FINE, "creating connection");
        try {
            connection = factory.newConnection();
        } catch (TimeoutException ex) {
            throw new IOException(ex);
        }
    }

    /**
     * Get a {@link Channel} for the specified key. If the key does not exist then a channel is created.
     * <p>
     * Note: Do not cache the returned Channel, as it could become invalid if the underlying connection is closed. The key is
     * usually an object that's requiring a channel.
     * <p>
     * @param key client specific key, usually a reference to themselves
     * <p>
     * @return Channel for this key, can change over time
     */
    public synchronized Channel getChannel(Object key) {
        Channel channel = null;
        do {
            channel = channels.computeIfAbsent(key, k -> {
                try {
                    LOG.log(Level.FINE, "creating channel");
                    return getConnection().createChannel();
                } catch (IOException ex) {
                    throw new UncheckedIOException(ex);
                }
            });
            if (channel != null && !channel.isOpen()) {
                LOG.log(Level.FINE, "discarding dead channel");

                channels.remove(key);
                channel = null;
            }
        } while (channel == null);

        return channel;
    }

    public void close(Object key, Channel channel) {
        if (channels.remove(key, channel)) {
            try {
                channel.close();
            } catch (TimeoutException | ShutdownSignalException ex) {
                // Ignore
            } catch (IOException ex) {
                Logger.getLogger(RabbitConnection.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    /**
     * Close the underlying connection and all Channels to it
     */
    public synchronized void close() {
        LOG.log(Level.FINE, "closing connection");
        try {
            try {
                channels.forEach((n, c) -> {
                    try {
                        c.close();
                    } catch (Throwable t) {
                        // Ignore as we are cleaning up
                    }
                });
            } finally {
                if (connection != null) {
                    connection.close();
                }
            }
        } catch (Throwable t) {
            // Ignore as we are cleaning up
        } finally {
            channels.clear();
            connection = null;
        }
    }

}