// $Id: TCPGOSSIP.java,v 1.20 2006/10/11 14:42:42 belaban Exp $
package org.jgroups.protocols;
import org.jgroups.Address;
import org.jgroups.Event;
import org.jgroups.Message;
import org.jgroups.stack.GossipClient;
import org.jgroups.stack.IpAddress;
import java.util.*;
import java.net.UnknownHostException;
/**
* The TCPGOSSIP protocol layer retrieves the initial membership (used by the GMS when started
* by sending event FIND_INITIAL_MBRS down the stack).
* We do this by contacting one or more GossipRouters, which must be running at well-known
* addresses:ports. The responses should allow us to determine the coordinator whom 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 TCPGOSSIP requests with a TCPGOSSIP
* response.<p> The FIND_INITIAL_MBRS event will eventually be answered with a
* FIND_INITIAL_MBRS_OK event up the stack.
*
* @author Bela Ban
*/
public class TCPGOSSIP extends Discovery {
Vector initial_hosts=null; // (list of IpAddresses) hosts to be contacted for the initial membership
GossipClient gossip_client=null; // accesses the GossipRouter(s) to find initial mbrship
// we need to refresh the registration with the GossipRouter(s) periodically,
// so that our entries are not purged from the cache
long gossip_refresh_rate=20000;
final static Vector EMPTY_VECTOR=new Vector();
final static String name="TCPGOSSIP";
public String getName() {
return name;
}
public boolean setProperties(Properties props) {
String str;
str=props.getProperty("gossip_refresh_rate"); // wait for at most n members
if(str != null) {
gossip_refresh_rate=Integer.parseInt(str);
props.remove("gossip_refresh_rate");
}
str=props.getProperty("initial_hosts");
if(str != null) {
props.remove("initial_hosts");
try {
initial_hosts=createInitialHosts(str);
}
catch(UnknownHostException ex) {
if(log.isErrorEnabled())
log.error("failed creating initial hosts", ex);
return false;
}
}
if(initial_hosts == null || initial_hosts.size() == 0) {
if(log.isErrorEnabled()) log.error("initial_hosts must contain the address of at least one GossipRouter");
return false;
}
return super.setProperties(props);
}
public void start() throws Exception {
super.start();
if(gossip_client == null)
gossip_client=new GossipClient(initial_hosts, gossip_refresh_rate);
}
public void stop() {
super.stop();
if(gossip_client != null) {
gossip_client.stop();
gossip_client=null;
}
}
public void destroy() {
if(gossip_client != null) {
gossip_client.destroy();
gossip_client=null;
}
}
public void handleConnectOK() {
if(group_addr == null || local_addr == null) {
if(log.isErrorEnabled())
log.error("[CONNECT_OK]: group_addr or local_addr is null. " +
"cannot register with GossipRouter(s)");
}
else {
if(trace)
log.trace("[CONNECT_OK]: registering " + local_addr +
" under " + group_addr + " with GossipRouter");
gossip_client.register(group_addr, local_addr);
}
}
public void sendGetMembersRequest() {
Message msg, copy;
PingHeader hdr;
List tmp_mbrs;
Address mbr_addr;
if(group_addr == null) {
if(log.isErrorEnabled()) log.error("[FIND_INITIAL_MBRS]: group_addr is null, cannot get mbrship");
passUp(new Event(Event.FIND_INITIAL_MBRS_OK, EMPTY_VECTOR));
return;
}
if(trace) log.trace("fetching members from GossipRouter(s)");
tmp_mbrs=gossip_client.getMembers(group_addr);
if(tmp_mbrs == null || tmp_mbrs.size() == 0) {
if(log.isErrorEnabled()) log.error("[FIND_INITIAL_MBRS]: gossip client found no members");
passUp(new Event(Event.FIND_INITIAL_MBRS_OK, EMPTY_VECTOR));
return;
}
if(trace) log.trace("consolidated mbrs from GossipRouter(s) are " + tmp_mbrs);
// 1. 'Mcast' GET_MBRS_REQ message
hdr=new PingHeader(PingHeader.GET_MBRS_REQ, null);
msg=new Message(null);
msg.putHeader(name, hdr);
for(Iterator it=tmp_mbrs.iterator(); it.hasNext();) {
mbr_addr=(Address)it.next();
copy=msg.copy();
copy.setDest(mbr_addr);
if(trace) log.trace("[FIND_INITIAL_MBRS] sending PING request to " + copy.getDest());
passDown(new Event(Event.MSG, copy));
}
}
/* -------------------------- Private methods ---------------------------- */
/**
* Input is "daddy[8880],sindhu[8880],camille[5555]. Return list of IpAddresses
*/
private Vector createInitialHosts(String l) throws UnknownHostException {
Vector tmp=new Vector();
String host;
int port;
IpAddress addr;
StringTokenizer tok=new StringTokenizer(l, ",");
String t;
while(tok.hasMoreTokens()) {
try {
t=tok.nextToken();
host=t.substring(0, t.indexOf('['));
port=Integer.parseInt(t.substring(t.indexOf('[') + 1, t.indexOf(']')));
addr=new IpAddress(host, port);
tmp.addElement(addr);
}
catch(NumberFormatException e) {
if(log.isErrorEnabled()) log.error("exeption is " + e);
}
}
return tmp;
}
}