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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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package org.jgroups.protocols;

import org.jgroups.*;
import org.jgroups.util.NameCache;
import org.jgroups.util.Responses;

import java.io.InterruptedIOException;
import java.util.List;

import static org.jgroups.Message.Flag.*;
import static org.jgroups.Message.TransientFlag.DONT_LOOPBACK;


/**
 * The PING protocol retrieves the initial membership by mcasting a discovery request (via the multicast capable
 * transport) to all current cluster members
 * The responses should allow us to determine the coordinator which we have to contact, e.g. in case we want to join
 * the group.  When we are a server (after having received the BECOME_SERVER event), we'll respond to discovery requests
 * with a discovery response.
 * @author Bela Ban
 */
public class PING extends Discovery {

    public boolean isDynamic() {
        return true;
    }


    public void findMembers(List members, boolean initial_discovery, Responses responses) {
        try {
            sendDiscoveryRequest(cluster_name, members, initial_discovery);
        }
        catch(InterruptedIOException | InterruptedException ie) {
            ;
        }
        catch(Throwable ex) {
            log.error(String.format("%s: failed sending discovery request", local_addr), ex);
        }
    }


    protected void sendDiscoveryRequest(String cluster_name, List members_to_find, boolean initial_discovery) throws Exception {
        PhysicalAddress physical_addr=(PhysicalAddress)down(new Event(Event.GET_PHYSICAL_ADDRESS, local_addr));

        // https://issues.redhat.com/browse/JGRP-1670
        PingData data=new PingData(local_addr, false, NameCache.get(local_addr), physical_addr);
        if(members_to_find != null && members_to_find.size() <= max_members_in_discovery_request)
            data.mbrs(members_to_find);

        // message needs to have DONT_BUNDLE flag: if A sends message M to B, and we need to fetch B's physical
        // address, then the bundler thread blocks until the discovery request has returned. However, we cannot send
        // the discovery *request* until the bundler thread has returned from sending M
        PingHeader hdr=new PingHeader(PingHeader.GET_MBRS_REQ).clusterName(cluster_name).initialDiscovery(initial_discovery);
        Message msg=new BytesMessage(null).putHeader(getId(), hdr).setFlag(DONT_BUNDLE, OOB).setFlag(DONT_LOOPBACK);
        if(data != null)
            msg.setArray(marshal(data));
        sendMcastDiscoveryRequest(msg);
    }

    protected void sendMcastDiscoveryRequest(Message msg) {
        down_prot.down(msg);
    }
}