org.springframework.integration.ip.udp.MulticastReceivingChannelAdapter.java Source code

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Here is the source code for org.springframework.integration.ip.udp.MulticastReceivingChannelAdapter.java

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/*
 * Copyright 2002-2019 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.integration.ip.udp;

import java.io.IOException;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;

import org.springframework.messaging.MessagingException;

/**
 * Channel adapter that joins a multicast group and receives incoming packets and
 * sends them to an output channel.
 *
 * @author Gary Russell
 * @author Marcin Pilaczynski
 * @since 2.0
 */
public class MulticastReceivingChannelAdapter extends UnicastReceivingChannelAdapter {

    private final String group;

    /**
     * Constructs a MulticastReceivingChannelAdapter that listens for packets on the
     * specified multichannel address (group) and port.
     * @param group The multichannel address.
     * @param port The port.
     */
    public MulticastReceivingChannelAdapter(String group, int port) {
        super(port);
        this.group = group;
    }

    /**
     * Constructs a MulticastReceivingChannelAdapter that listens for packets on the
     * specified multichannel address (group) and port. Enables setting the lengthCheck
     * option, which expects a length to precede the incoming packets.
     * @param group The multichannel address.
     * @param port The port.
     * @param lengthCheck If true, enables the lengthCheck Option.
     */
    public MulticastReceivingChannelAdapter(String group, int port, boolean lengthCheck) {
        super(port, lengthCheck);
        this.group = group;
    }

    @Override
    public synchronized DatagramSocket getSocket() {
        if (getTheSocket() == null) {
            try {
                int port = getPort();
                MulticastSocket socket = port == 0 ? new MulticastSocket() : new MulticastSocket(port);
                String localAddress = this.getLocalAddress();
                if (localAddress != null) {
                    InetAddress whichNic = InetAddress.getByName(localAddress);
                    socket.setInterface(whichNic);
                }
                setSocketAttributes(socket);
                socket.joinGroup(InetAddress.getByName(this.group));
                setSocket(socket);
            } catch (IOException e) {
                throw new MessagingException("failed to create DatagramSocket", e);
            }
        }
        return super.getSocket();
    }

}