package org.jgroups.protocols.pbcast;
import org.jgroups.*;
import org.jgroups.annotations.*;
import org.jgroups.conf.PropertyConverters;
import org.jgroups.protocols.TP;
import org.jgroups.stack.*;
import org.jgroups.util.BoundedList;
import org.jgroups.util.Digest;
import org.jgroups.util.TimeScheduler;
import org.jgroups.util.Util;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* Negative AcKnowledgement layer (NAKs). Messages are assigned a monotonically
* increasing sequence number (seqno). Receivers deliver messages ordered
* according to seqno and request retransmission of missing messages.<br/>
* Retransmit requests are usually sent to the original sender of a message, but
* this can be changed by xmit_from_random_member (send to random member) or
* use_mcast_xmit_req (send to everyone). Responses can also be sent to everyone
* instead of the requester by setting use_mcast_xmit to true.
*
* @author Bela Ban
*/
@MBean(description="Reliable transmission multipoint FIFO protocol")
@DeprecatedProperty(names={"max_xmit_size", "eager_lock_release", "stats_list_size", "max_xmit_buf_size",
"enable_xmit_time_stats"})
public class NAKACK extends Protocol implements Retransmitter.RetransmitCommand, NakReceiverWindow.Listener, TP.ProbeHandler {
/** the weight with which we take the previous smoothed average into account, WEIGHT should be >0 and <= 1 */
private static final double WEIGHT=0.9;
private static final double INITIAL_SMOOTHED_AVG=30.0;
private static final int NUM_REBROADCAST_MSGS=3;
/* ----------------------------------------------------- Properties --------------------- ------------------------------------ */
@Property(name="retransmit_timeout", converter=PropertyConverters.LongArray.class, description="Timeout before requesting retransmissions. Default is 600, 1200, 2400, 4800")
private long[] retransmit_timeouts= { 600, 1200, 2400, 4800 }; // time(s) to wait before requesting retransmission
@Deprecated
@Property(description="Garbage collection lag")
private int gc_lag=20; // number of msgs garbage collection lags behind
@Property(description="Max number of messages to be removed from a NakReceiverWindow. This property might " +
"get removed anytime, so don't use it !")
private int max_msg_batch_size=20000;
/**
* Retransmit messages using multicast rather than unicast. This has the advantage that, if many receivers
* lost a message, the sender only retransmits once
*/
@Property(description="Retransmit messages using multicast rather than unicast")
private boolean use_mcast_xmit=true;
/**
* Use a multicast to request retransmission of missing messages. This may
* be costly as every member in the cluster will send a response
*/
@Property(description="Use a multicast to request retransmission of missing messages. Default is false")
private boolean use_mcast_xmit_req=false;
/**
* Ask a random member for retransmission of a missing message. If set to
* true, discard_delivered_msgs will be set to false
*/
@Property(description="Ask a random member for retransmission of a missing message. Default is false")
private boolean xmit_from_random_member=false;
/**
* The first value (in milliseconds) to use in the exponential backoff
* retransmission mechanism. Only enabled if the value is > 0
*/
@Property(description="The first value (in milliseconds) to use in the exponential backoff. Enabled if greater than 0. Default is 0")
private long exponential_backoff=0;
/**
* If enabled, we use statistics gathered from actual retransmission times
* to compute the new retransmission times
*/
@Property(description="Use statistics gathered from actual retransmission times to compute new retransmission times. Default is false")
private boolean use_stats_for_retransmission=false;
@Property(description="Whether to use the old retransmitter which retransmits individual messages or the new one " +
"which uses ranges of retransmitted messages. Default is true. Note that this property will be removed in 3.0; " +
"it is only used to switch back to the old (and proven) retransmitter mechanism if issues occur")
private boolean use_range_based_retransmitter=true;
/**
* Messages that have been received in order are sent up the stack (=
* delivered to the application). Delivered messages are removed from
* NakReceiverWindow.xmit_table and moved to
* NakReceiverWindow.delivered_msgs, where they are later garbage collected
* (by STABLE). Since we do retransmits only from sent messages, never
* received or delivered messages, we can turn the moving to delivered_msgs
* off, so we don't keep the message around, and don't need to wait for
* garbage collection to remove them.
*/
@Property(description="Should messages delivered to application be discarded")
private boolean discard_delivered_msgs=false;
@Property(description="Size of retransmission history. Default is 50 entries")
private int xmit_history_max_size=50;
@Property(description="Timeout to rebroadcast messages. Default is 2000 msec")
private long max_rebroadcast_timeout=2000;
/**
* When not finding a message on an XMIT request, include the last N
* stability messages in the error message
*/
@Property(description="Should stability history be printed if we fail in retransmission. Default is false")
protected boolean print_stability_history_on_failed_xmit=false;
/** If true, logs messages discarded because received from other members */
@Property(description="discards warnings about promiscuous traffic")
private boolean log_discard_msgs=true;
@Property(description="If true, trashes warnings about retransmission messages not found in the xmit_table (used for testing)")
private boolean log_not_found_msgs=true;
@Property(description="Number of rows of the matrix in the retransmission table (only for experts)",writable=false)
int xmit_table_num_rows=5;
@Property(description="Number of elements of a row of the matrix in the retransmission table (only for experts). " +
"The capacity of the matrix is xmit_table_num_rows * xmit_table_msgs_per_row",writable=false)
int xmit_table_msgs_per_row=10000;
@Property(description="Resize factor of the matrix in the retransmission table (only for experts)",writable=false)
double xmit_table_resize_factor=1.2;
@Property(description="Number of milliseconds after which the matrix in the retransmission table " +
"is compacted (only for experts)",writable=false)
long xmit_table_max_compaction_time=10 * 60 * 1000;
/* -------------------------------------------------- JMX ---------------------------------------------------------- */
@ManagedAttribute(description="Number of retransmit requests received")
private long xmit_reqs_received;
@ManagedAttribute(description="Number of retransmit requests sent")
private long xmit_reqs_sent;
@ManagedAttribute(description="Number of retransmit responses received")
private long xmit_rsps_received;
@ManagedAttribute(description="Number of retransmit responses sent")
private long xmit_rsps_sent;
@ManagedAttribute(description="Number of missing messages received")
private long missing_msgs_received;
/** Captures stats on XMIT_REQS, XMIT_RSPS per sender */
private ConcurrentMap<Address, StatsEntry> sent=Util.createConcurrentMap();
/** Captures stats on XMIT_REQS, XMIT_RSPS per receiver */
private ConcurrentMap<Address, StatsEntry> received=Util.createConcurrentMap();
/** Per-sender map of seqnos and timestamps, to keep track of avg times for retransmission of messages */
private final ConcurrentMap<Address, ConcurrentMap<Long, Long>> xmit_stats=Util.createConcurrentMap();
/** Maintains a list of the last N retransmission times (duration to retransmit a message) for all members */
private final ConcurrentMap<Address, BoundedList<Long>> xmit_times_history=Util.createConcurrentMap();
/**
* Maintains a smoothed average of the retransmission times per sender,
* these are the actual values that are used for new retransmission requests
*/
private final Map<Address,Double> smoothed_avg_xmit_times=new HashMap<Address,Double>();
/** Keeps the last 50 retransmit requests */
private final BoundedList<String> xmit_history=new BoundedList<String>(50);
/* ------------------------------------------------- Fields ------------------------------------------------------------------------- */
private boolean is_server=false;
private Address local_addr=null;
private final List<Address> members=new CopyOnWriteArrayList<Address>();
private View view;
@GuardedBy("seqno_lock")
private long seqno=0; // current message sequence number (starts with 1)
private final Lock seqno_lock=new ReentrantLock();
/** Map to store sent and received messages (keyed by sender) */
private final ConcurrentMap<Address,NakReceiverWindow> xmit_table=Util.createConcurrentMap();
private volatile boolean leaving=false;
private volatile boolean running=false;
private TimeScheduler timer=null;
private final Lock rebroadcast_lock=new ReentrantLock();
private final Condition rebroadcast_done=rebroadcast_lock.newCondition();
// set during processing of a rebroadcast event
private volatile boolean rebroadcasting=false;
private final Lock rebroadcast_digest_lock=new ReentrantLock();
@GuardedBy("rebroadcast_digest_lock")
private Digest rebroadcast_digest=null;
/** BoundedList<Digest>, keeps the last 10 stability messages */
protected final BoundedList<Digest> stability_msgs=new BoundedList<Digest>(10);
/** Keeps a bounded list of the last N digest sets */
protected final BoundedList<String> digest_history=new BoundedList<String>(10);
public NAKACK() {
}
@Deprecated
public static int getUndeliveredMessages() {
return 0;
}
public long getXmitRequestsReceived() {return xmit_reqs_received;}
public long getXmitRequestsSent() {return xmit_reqs_sent;}
public long getXmitResponsesReceived() {return xmit_rsps_received;}
public long getXmitResponsesSent() {return xmit_rsps_sent;}
public long getMissingMessagesReceived() {return missing_msgs_received;}
@ManagedAttribute(description="Total number of missing messages")
public int getPendingRetransmissionRequests() {
int num=0;
for(NakReceiverWindow win: xmit_table.values()) {
num+=win.getPendingXmits();
}
return num;
}
@ManagedAttribute
public int getXmitTableSize() {
int num=0;
for(NakReceiverWindow win: xmit_table.values()) {
num+=win.size();
}
return num;
}
@ManagedAttribute
public long getCurrentSeqno() {return seqno;}
@ManagedOperation
public String printRetransmitStats() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet())
sb.append(entry.getKey()).append(": ").append(entry.getValue().printRetransmitStats()).append("\n");
return sb.toString();
}
public int getReceivedTableSize() {
return getPendingRetransmissionRequests();
}
/**
* Please don't use this method; it is only provided for unit testing !
* @param mbr
* @return
*/
public NakReceiverWindow getWindow(Address mbr) {
return xmit_table.get(mbr);
}
/**
* Only used for unit tests, don't use !
* @param timer
*/
public void setTimer(TimeScheduler timer) {
this.timer=timer;
}
public void resetStats() {
xmit_reqs_received=xmit_reqs_sent=xmit_rsps_received=xmit_rsps_sent=missing_msgs_received=0;
sent.clear();
received.clear();
stability_msgs.clear();
digest_history.clear();
xmit_history.clear();
}
public void init() throws Exception {
if(xmit_from_random_member) {
if(discard_delivered_msgs) {
discard_delivered_msgs=false;
log.warn("xmit_from_random_member set to true: changed discard_delivered_msgs to false");
}
}
TP transport=getTransport();
if(transport != null) {
transport.registerProbeHandler(this);
if(!transport.supportsMulticasting()) {
if(use_mcast_xmit) {
log.warn("use_mcast_xmit should not be used because the transport (" + transport.getName() +
") does not support IP multicasting; setting use_mcast_xmit to false");
use_mcast_xmit=false;
}
if(use_mcast_xmit_req) {
log.warn("use_mcast_xmit_req should not be used because the transport (" + transport.getName() +
") does not support IP multicasting; setting use_mcast_xmit_req to false");
use_mcast_xmit_req=false;
}
}
}
}
@Deprecated
public int getGcLag() {
return gc_lag;
}
@Deprecated
public void setGcLag(int gc_lag) {
this.gc_lag=gc_lag;
}
public boolean isUseMcastXmit() {
return use_mcast_xmit;
}
public void setUseMcastXmit(boolean use_mcast_xmit) {
this.use_mcast_xmit=use_mcast_xmit;
}
public boolean isXmitFromRandomMember() {
return xmit_from_random_member;
}
public void setXmitFromRandomMember(boolean xmit_from_random_member) {
this.xmit_from_random_member=xmit_from_random_member;
}
public boolean isDiscardDeliveredMsgs() {
return discard_delivered_msgs;
}
public void setDiscardDeliveredMsgs(boolean discard_delivered_msgs) {
boolean old=this.discard_delivered_msgs;
this.discard_delivered_msgs=discard_delivered_msgs;
}
@Deprecated
public static int getMaxXmitBufSize() {
return 0;
}
@Deprecated
public static void setMaxXmitBufSize(int max_xmit_buf_size) {
;
}
/**
*
* @return
* @deprecated removed in 2.6
*/
public static long getMaxXmitSize() {
return -1;
}
/**
*
* @param max_xmit_size
* @deprecated removed in 2.6
*/
public void setMaxXmitSize(long max_xmit_size) {
}
public void setLogDiscardMessages(boolean flag) {
log_discard_msgs=flag;
}
public void setLogDiscardMsgs(boolean flag) {
setLogDiscardMessages(flag);
}
public boolean getLogDiscardMessages() {
return log_discard_msgs;
}
public Map<String,Object> dumpStats() {
Map<String,Object> retval=super.dumpStats();
retval.put("msgs", printMessages());
return retval;
}
public String printStats() {
StringBuilder sb=new StringBuilder();
sb.append("sent:\n");
for(Iterator<Map.Entry<Address, StatsEntry>> it=sent.entrySet().iterator(); it.hasNext();) {
Map.Entry<Address, StatsEntry> entry=it.next();
Object key=entry.getKey();
if(key == null || key == Global.NULL) key="<mcast dest>";
StatsEntry val=entry.getValue();
sb.append(key).append(": ").append(val).append("\n");
}
sb.append("\nreceived:\n");
for(Iterator<Map.Entry<Address, StatsEntry>> it=received.entrySet().iterator(); it.hasNext();) {
Map.Entry<Address, StatsEntry> entry=it.next();
Object key=entry.getKey();
if(key == null || key == Global.NULL) key="<mcast dest>";
StatsEntry val=entry.getValue();
sb.append(key).append(": ").append(val).append("\n");
}
sb.append("\nStability messages received\n");
sb.append(printStabilityMessages()).append("\n");
return sb.toString();
}
@ManagedOperation(description="TODO")
public String printStabilityMessages() {
StringBuilder sb=new StringBuilder();
sb.append(Util.printListWithDelimiter(stability_msgs, "\n"));
return sb.toString();
}
public String printStabilityHistory() {
StringBuilder sb=new StringBuilder();
int i=1;
for(Digest digest: stability_msgs) {
sb.append(i++).append(": ").append(digest).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="Keeps information about the last N times a digest was set or merged")
public String printDigestHistory() {
StringBuilder sb=new StringBuilder(local_addr + ":\n");
for(String tmp: digest_history)
sb.append(tmp).append("\n");
return sb.toString();
}
@ManagedOperation(description="TODO")
public String printLossRates() {
StringBuilder sb=new StringBuilder();
NakReceiverWindow win;
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
win=entry.getValue();
sb.append(entry.getKey()).append(": ").append(win.printLossRate()).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="Returns the sizes of all NakReceiverWindow.RetransmitTables")
public String printRetransmitTableSizes() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
NakReceiverWindow win=entry.getValue();
sb.append(entry.getKey() + ": ").append(win.getRetransmiTableSize())
.append(" (capacity=" + win.getRetransmitTableCapacity())
.append(", fill factor=" + win.getRetransmitTableFillFactor() + "%)\n");
}
return sb.toString();
}
@ManagedOperation(description="Compacts the retransmission tables")
public void compact() {
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
NakReceiverWindow win=entry.getValue();
win.compact();
}
}
@ManagedAttribute
public double getAverageLossRate() {
double retval=0.0;
int count=0;
if(xmit_table.isEmpty())
return 0.0;
for(NakReceiverWindow win: xmit_table.values()) {
retval+=win.getLossRate();
count++;
}
return retval / (double)count;
}
@ManagedAttribute
public double getAverageSmoothedLossRate() {
double retval=0.0;
int count=0;
if(xmit_table.isEmpty())
return 0.0;
for(NakReceiverWindow win: xmit_table.values()) {
retval+=win.getSmoothedLossRate();
count++;
}
return retval / (double)count;
}
public Vector<Integer> providedUpServices() {
Vector<Integer> retval=new Vector<Integer>(5);
retval.addElement(new Integer(Event.GET_DIGEST));
retval.addElement(new Integer(Event.SET_DIGEST));
retval.addElement(new Integer(Event.OVERWRITE_DIGEST));
retval.addElement(new Integer(Event.MERGE_DIGEST));
return retval;
}
public void start() throws Exception {
timer=getTransport().getTimer();
if(timer == null)
throw new Exception("timer is null");
running=true;
leaving=false;
}
public void stop() {
running=false;
reset(); // clears sent_msgs and destroys all NakReceiverWindows
}
/**
* <b>Callback</b>. Called by superclass when event may be handled.<p> <b>Do not use <code>down_prot.down()</code> in this
* method as the event is passed down by default by the superclass after this method returns !</b>
*/
public Object down(Event evt) {
switch(evt.getType()) {
case Event.MSG:
Message msg=(Message)evt.getArg();
Address dest=msg.getDest();
if(dest != null && !dest.isMulticastAddress() || msg.isFlagSet(Message.NO_RELIABILITY))
break; // unicast address: not null and not mcast, pass down unchanged
send(evt, msg);
return null; // don't pass down the stack
case Event.STABLE: // generated by STABLE layer. Delete stable messages passed in arg
stable((Digest)evt.getArg());
return null; // do not pass down further (Bela Aug 7 2001)
case Event.GET_DIGEST:
return getDigest();
case Event.SET_DIGEST:
setDigest((Digest)evt.getArg());
return null;
case Event.OVERWRITE_DIGEST:
overwriteDigest((Digest)evt.getArg());
return null;
case Event.MERGE_DIGEST:
mergeDigest((Digest)evt.getArg());
return null;
case Event.TMP_VIEW:
View tmp_view=(View)evt.getArg();
Vector<Address> mbrs=tmp_view.getMembers();
members.clear();
members.addAll(mbrs);
// adjustReceivers(false);
break;
case Event.VIEW_CHANGE:
tmp_view=(View)evt.getArg();
mbrs=tmp_view.getMembers();
members.clear();
members.addAll(mbrs);
view=tmp_view;
adjustReceivers(members);
is_server=true; // check vids from now on
Set<Address> tmp=new LinkedHashSet<Address>(members);
tmp.add(null); // for null destination (= mcast)
sent.keySet().retainAll(tmp);
received.keySet().retainAll(tmp);
xmit_stats.keySet().retainAll(tmp);
// in_progress.keySet().retainAll(mbrs); // remove elements which are not in the membership
break;
case Event.BECOME_SERVER:
is_server=true;
break;
case Event.SET_LOCAL_ADDRESS:
local_addr=(Address)evt.getArg();
break;
case Event.DISCONNECT:
leaving=true;
reset();
break;
case Event.REBROADCAST:
rebroadcasting=true;
rebroadcast_digest=(Digest)evt.getArg();
try {
rebroadcastMessages();
}
finally {
rebroadcasting=false;
rebroadcast_digest_lock.lock();
try {
rebroadcast_digest=null;
}
finally {
rebroadcast_digest_lock.unlock();
}
}
return null;
}
return down_prot.down(evt);
}
/**
* <b>Callback</b>. Called by superclass when event may be handled.<p> <b>Do not use <code>PassUp</code> in this
* method as the event is passed up by default by the superclass after this method returns !</b>
*/
public Object up(Event evt) {
switch(evt.getType()) {
case Event.MSG:
Message msg=(Message)evt.getArg();
if(msg.isFlagSet(Message.NO_RELIABILITY))
break;
NakAckHeader hdr=(NakAckHeader)msg.getHeader(this.id);
if(hdr == null)
break; // pass up (e.g. unicast msg)
if(!is_server) { // discard messages while not yet server (i.e., until JOIN has returned)
if(log.isTraceEnabled())
log.trace("message " + msg.getSrc() + "::" + hdr.seqno + " was discarded (not yet server)");
return null;
}
// Changed by bela Jan 29 2003: we must not remove the header, otherwise further xmit requests will fail !
//hdr=(NakAckHeader)msg.removeHeader(getName());
switch(hdr.type) {
case NakAckHeader.MSG:
handleMessage(msg, hdr);
return null; // transmitter passes message up for us !
case NakAckHeader.XMIT_REQ:
if(hdr.range == null) {
if(log.isErrorEnabled()) {
log.error("XMIT_REQ: range of xmit msg is null; discarding request from " + msg.getSrc());
}
return null;
}
handleXmitReq(msg.getSrc(), hdr.range.low, hdr.range.high, hdr.sender);
return null;
case NakAckHeader.XMIT_RSP:
handleXmitRsp(msg, hdr);
return null;
default:
if(log.isErrorEnabled()) {
log.error("NakAck header type " + hdr.type + " not known !");
}
return null;
}
case Event.STABLE: // generated by STABLE layer. Delete stable messages passed in arg
stable((Digest)evt.getArg());
return null; // do not pass up further (Bela Aug 7 2001)
case Event.SUSPECT:
// release the promise if rebroadcasting is in progress... otherwise we wait forever. there will be a new
// flush round anyway
if(rebroadcasting) {
cancelRebroadcasting();
}
break;
}
return up_prot.up(evt);
}
/* --------------------------------- Private Methods --------------------------------------- */
/**
* Adds the message to the sent_msgs table and then passes it down the stack. Change Bela Ban May 26 2002: we don't
* store a copy of the message, but a reference ! This saves us a lot of memory. However, this also means that a
* message should not be changed after storing it in the sent-table ! See protocols/DESIGN for details.
* Made seqno increment and adding to sent_msgs atomic, e.g. seqno won't get incremented if adding to
* sent_msgs fails e.g. due to an OOM (see http://jira.jboss.com/jira/browse/JGRP-179). bela Jan 13 2006
*/
private void send(Event evt, Message msg) {
if(msg == null)
throw new NullPointerException("msg is null; event is " + evt);
if(!running) {
if(log.isTraceEnabled())
log.trace("[" + local_addr + "] discarded message as we're not in the 'running' state, message: " + msg);
return;
}
long msg_id;
NakReceiverWindow win=xmit_table.get(local_addr);
if(win == null) { // discard message if there is no entry for local_addr
if(log.isWarnEnabled() && log_discard_msgs)
log.warn(local_addr + ": discarded message from " + local_addr + " with no window, my view is " + view);
return;
}
if(msg.getSrc() == null)
msg.setSrc(local_addr); // this needs to be done so we can check whether the message sender is the local_addr
seqno_lock.lock();
try {
try { // incrementing seqno and adding the msg to sent_msgs needs to be atomic
msg_id=seqno +1;
msg.putHeader(this.id, NakAckHeader.createMessageHeader(msg_id));
win.add(msg_id, msg);
seqno=msg_id;
}
catch(Throwable t) {
throw new RuntimeException("failure adding msg " + msg + " to the retransmit table for " + local_addr, t);
}
}
finally {
seqno_lock.unlock();
}
try { // moved down_prot.down() out of synchronized clause (bela Sept 7 2006) http://jira.jboss.com/jira/browse/JGRP-300
if(log.isTraceEnabled())
log.trace("sending " + local_addr + "#" + msg_id);
down_prot.down(evt); // if this fails, since msg is in sent_msgs, it can be retransmitted
}
catch(Throwable t) { // eat the exception, don't pass it up the stack
if(log.isWarnEnabled()) {
log.warn("failure passing message down", t);
}
}
}
/**
* Finds the corresponding NakReceiverWindow and adds the message to it (according to seqno). Then removes as many
* messages as possible from the NRW and passes them up the stack. Discards messages from non-members.
*/
private void handleMessage(Message msg, NakAckHeader hdr) {
Address sender=msg.getSrc();
if(sender == null) {
if(log.isErrorEnabled())
log.error("sender of message is null");
return;
}
NakReceiverWindow win=xmit_table.get(sender);
if(win == null) { // discard message if there is no entry for sender
if(leaving)
return;
if(log.isWarnEnabled() && log_discard_msgs)
log.warn(local_addr + ": dropped message from " + sender + " (not in table " + xmit_table.keySet() +"), view=" + view);
return;
}
boolean loopback=local_addr.equals(sender);
boolean added=loopback || win.add(hdr.seqno, msg);
if(added && log.isTraceEnabled())
log.trace(new StringBuilder().append(local_addr).append(": received ").append(sender).append('#').append(hdr.seqno));
// OOB msg is passed up. When removed, we discard it. Affects ordering: http://jira.jboss.com/jira/browse/JGRP-379
if(added && msg.isFlagSet(Message.OOB)) {
if(loopback)
msg=win.get(hdr.seqno); // we *have* to get a message, because loopback means we didn't add it to win !
if(msg != null && msg.isFlagSet(Message.OOB)) {
if(msg.setTransientFlagIfAbsent(Message.OOB_DELIVERED))
up_prot.up(new Event(Event.MSG, msg));
}
}
// Efficient way of checking whether another thread is already processing messages from 'sender'.
// If that's the case, we return immediately and let the existing thread process our message
// (https://jira.jboss.org/jira/browse/JGRP-829). Benefit: fewer threads blocked on the same lock, these threads
// can be returned to the thread pool
final AtomicBoolean processing=win.getProcessing();
if(!processing.compareAndSet(false, true)) {
return;
}
boolean remove_msgs=discard_delivered_msgs && !loopback;
boolean released_processing=false;
try {
while(true) {
// we're removing a msg and set processing to false (if null) *atomically* (wrt to add())
List<Message> msgs=win.removeMany(processing, remove_msgs, max_msg_batch_size);
if(msgs == null || msgs.isEmpty()) {
released_processing=true;
if(rebroadcasting)
checkForRebroadcasts();
return;
}
for(final Message msg_to_deliver: msgs) {
// discard OOB msg if it has already been delivered (http://jira.jboss.com/jira/browse/JGRP-379)
if(msg_to_deliver.isFlagSet(Message.OOB) && !msg_to_deliver.setTransientFlagIfAbsent(Message.OOB_DELIVERED))
continue;
//msg_to_deliver.removeHeader(getName()); // Changed by bela Jan 29 2003: not needed (see above)
try {
up_prot.up(new Event(Event.MSG, msg_to_deliver));
}
catch(Throwable t) {
log.error("couldn't deliver message " + msg_to_deliver, t);
}
}
}
}
finally {
// processing is always set in win.remove(processing) above and never here ! This code is just a
// 2nd line of defense should there be an exception before win.remove(processing) sets processing
if(!released_processing)
processing.set(false);
}
}
/**
* Retransmits messsages first_seqno to last_seqno from original_sender from xmit_table to xmit_requester,
* called when XMIT_REQ is received.
* @param xmit_requester The sender of the XMIT_REQ, we have to send the requested copy of the message to this address
* @param first_seqno The first sequence number to be retransmitted (<= last_seqno)
* @param last_seqno The last sequence number to be retransmitted (>= first_seqno)
* @param original_sender The member who originally sent the messsage. Guaranteed to be non-null
*/
private void handleXmitReq(Address xmit_requester, long first_seqno, long last_seqno, Address original_sender) {
if(first_seqno > last_seqno)
return;
if(log.isTraceEnabled()) {
StringBuilder sb=new StringBuilder();
sb.append(local_addr).append(": received xmit request from ").append(xmit_requester).append(" for ");
sb.append(original_sender).append(" [").append(first_seqno).append(" - ").append(last_seqno).append("]");
log.trace(sb.toString());
}
if(stats) {
xmit_reqs_received+=last_seqno - first_seqno +1;
updateStats(received, xmit_requester, 1, 0, 0);
}
NakReceiverWindow win=xmit_table.get(original_sender);
if(win == null) {
if(log.isErrorEnabled()) {
StringBuilder sb=new StringBuilder();
sb.append("(requester=").append(xmit_requester).append(", local_addr=").append(this.local_addr);
sb.append(") ").append(original_sender).append(" not found in retransmission table");
// don't print the table unless we are in trace mode because it can be LARGE
if (log.isTraceEnabled()) {
sb.append(":\n").append(printMessages());
}
if(print_stability_history_on_failed_xmit) {
sb.append(" (stability history:\n").append(printStabilityHistory());
}
log.error(sb.toString());
}
return;
}
long diff=last_seqno - first_seqno +1;
if(diff >= 10) {
List<Message> msgs=win.get(first_seqno, last_seqno);
if(msgs != null) {
for(Message msg: msgs)
sendXmitRsp(xmit_requester, msg);
}
}
else {
for(long i=first_seqno; i <= last_seqno; i++) {
Message msg=win.get(i);
if(msg == null) {
if(log.isWarnEnabled() && log_not_found_msgs && !local_addr.equals(xmit_requester)) {
StringBuilder sb=new StringBuilder();
sb.append("(requester=").append(xmit_requester).append(", local_addr=").append(this.local_addr);
sb.append(") message ").append(original_sender).append("::").append(i);
sb.append(" not found in retransmission table of ").append(original_sender).append(":\n").append(win);
if(print_stability_history_on_failed_xmit) {
sb.append(" (stability history:\n").append(printStabilityHistory());
}
log.warn(sb.toString());
}
continue;
}
sendXmitRsp(xmit_requester, msg);
}
}
}
private void cancelRebroadcasting() {
rebroadcast_lock.lock();
try {
rebroadcasting=false;
rebroadcast_done.signalAll();
}
finally {
rebroadcast_lock.unlock();
}
}
private static void updateStats(ConcurrentMap<Address,StatsEntry> map, Address key, int req, int rsp, int missing) {
StatsEntry entry=map.get(key);
if(entry == null) {
entry=new StatsEntry();
StatsEntry tmp=map.putIfAbsent(key, entry);
if(tmp != null)
entry=tmp;
}
entry.xmit_reqs+=req;
entry.xmit_rsps+=rsp;
entry.missing_msgs_rcvd+=missing;
}
/**
* Sends a message msg to the requester. We have to wrap the original message into a retransmit message, as we need
* to preserve the original message's properties, such as src, headers etc.
* @param dest
* @param msg
*/
private void sendXmitRsp(Address dest, Message msg) {
if(msg == null) {
if(log.isErrorEnabled())
log.error("message is null, cannot send retransmission");
return;
}
if(stats) {
xmit_rsps_sent++;
updateStats(sent, dest, 0, 1, 0);
}
if(msg.getSrc() == null)
msg.setSrc(local_addr);
if(use_mcast_xmit) { // we simply send the original multicast message
down_prot.down(new Event(Event.MSG, msg));
return;
}
Message xmit_msg=msg.copy(true, true); // copy payload and headers
xmit_msg.setDest(dest);
NakAckHeader hdr=(NakAckHeader)xmit_msg.getHeader(id);
hdr.type=NakAckHeader.XMIT_RSP; // change the type in the copy from MSG --> XMIT_RSP
down_prot.down(new Event(Event.MSG, xmit_msg));
}
private void handleXmitRsp(Message msg, NakAckHeader hdr) {
if(msg == null)
return;
try {
if(stats) {
xmit_rsps_received++;
updateStats(received, msg.getSrc(), 0, 1, 0);
}
msg.setDest(null);
hdr.type=NakAckHeader.MSG; // change the type back from XMIT_RSP --> MSG
up(new Event(Event.MSG, msg));
if(rebroadcasting)
checkForRebroadcasts();
}
catch(Exception ex) {
if(log.isErrorEnabled()) {
log.error("failed reading retransmitted message", ex);
}
}
}
/**
* Takes the argument highest_seqnos and compares it to the current digest. If the current digest has fewer messages,
* then send retransmit messages for the missing messages. Return when all missing messages have been received. If
* we're waiting for a missing message from P, and P crashes while waiting, we need to exclude P from the wait set.
*/
private void rebroadcastMessages() {
Digest my_digest;
Map<Address,Digest.Entry> their_digest;
Address sender;
Digest.Entry their_entry, my_entry;
long their_high, my_high;
long sleep=max_rebroadcast_timeout / NUM_REBROADCAST_MSGS;
long wait_time=max_rebroadcast_timeout, start=System.currentTimeMillis();
while(wait_time > 0) {
rebroadcast_digest_lock.lock();
try {
if(rebroadcast_digest == null)
break;
their_digest=rebroadcast_digest.getSenders();
}
finally {
rebroadcast_digest_lock.unlock();
}
my_digest=getDigest();
boolean xmitted=false;
for(Map.Entry<Address,Digest.Entry> entry: their_digest.entrySet()) {
sender=entry.getKey();
their_entry=entry.getValue();
my_entry=my_digest.get(sender);
if(my_entry == null)
continue;
their_high=their_entry.getHighest();
// Cannot ask for 0 to be retransmitted because the first seqno in NAKACK and UNICAST(2) is always 1 !
// Also, we need to ask for retransmission of my_high+1, because we already *have* my_high, and don't
// need it, so the retransmission range is [my_high+1 .. their_high]: *exclude* my_high, but *include*
// their_high
my_high=Math.max(1, my_entry.getHighest() +1);
if(their_high > my_high) {
if(log.isTraceEnabled())
log.trace("[" + local_addr + "] fetching " + my_high + "-" + their_high + " from " + sender);
retransmit(my_high, their_high, sender, true); // use multicast to send retransmit request
xmitted=true;
}
}
if(!xmitted)
return; // we're done; no retransmissions are needed anymore. our digest is >= rebroadcast_digest
rebroadcast_lock.lock();
try {
try {
my_digest=getDigest();
rebroadcast_digest_lock.lock();
try {
if(!rebroadcasting || my_digest.isGreaterThanOrEqual(rebroadcast_digest))
return;
}
finally {
rebroadcast_digest_lock.unlock();
}
rebroadcast_done.await(sleep, TimeUnit.MILLISECONDS);
wait_time-=(System.currentTimeMillis() - start);
}
catch(InterruptedException e) {
}
}
finally {
rebroadcast_lock.unlock();
}
}
}
protected void checkForRebroadcasts() {
Digest tmp=getDigest();
boolean cancel_rebroadcasting;
rebroadcast_digest_lock.lock();
try {
cancel_rebroadcasting=tmp.isGreaterThanOrEqual(rebroadcast_digest);
}
finally {
rebroadcast_digest_lock.unlock();
}
if(cancel_rebroadcasting) {
cancelRebroadcasting();
}
}
/**
* Remove old members from NakReceiverWindows. Essentially removes all entries from xmit_table that are not
* in <code>members</code>. This method is not called concurrently multiple times
*/
private void adjustReceivers(List<Address> new_members) {
for(Address member: xmit_table.keySet()) {
if(!new_members.contains(member)) {
if(local_addr != null && local_addr.equals(member))
continue;
NakReceiverWindow win=xmit_table.remove(member);
win.destroy();
if(log.isDebugEnabled())
log.debug("removed " + member + " from xmit_table (not member anymore)");
}
}
}
/**
* Returns a message digest: for each member P the lowest, highest delivered and highest received seqno is added
*/
public Digest getDigest() {
final Map<Address,Digest.Entry> map=new HashMap<Address,Digest.Entry>();
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
Address sender=entry.getKey(); // guaranteed to be non-null (CCHM)
NakReceiverWindow win=entry.getValue(); // guaranteed to be non-null (CCHM)
long[] digest=win.getDigest();
map.put(sender, new Digest.Entry(digest[0], digest[1], digest[2]));
}
return new Digest(map);
}
/**
* Creates a NakReceiverWindow for each sender in the digest according to the sender's seqno. If NRW already exists,
* reset it.
*/
private void setDigest(Digest digest) {
setDigest(digest, false);
}
/**
* For all members of the digest, adjust the NakReceiverWindows in xmit_table. If no entry
* exists, create one with the initial seqno set to the seqno of the member in the digest. If the member already
* exists, and is not the local address, replace it with the new entry (http://jira.jboss.com/jira/browse/JGRP-699)
* if the digest's seqno is greater than the seqno in the window.
*/
private void mergeDigest(Digest digest) {
setDigest(digest, true);
}
/**
* Overwrites existing entries, but does NOT remove entries not found in the digest
* @param digest
*/
private void overwriteDigest(Digest digest) {
if(digest == null)
return;
StringBuilder sb=new StringBuilder("\n[overwriteDigest()]\n");
sb.append("existing digest: " + getDigest()).append("\nnew digest: " + digest);
for(Map.Entry<Address, Digest.Entry> entry: digest.getSenders().entrySet()) {
Address sender=entry.getKey();
Digest.Entry val=entry.getValue();
if(sender == null || val == null)
continue;
long highest_delivered_seqno=val.getHighestDeliveredSeqno();
long low_seqno=val.getLow();
NakReceiverWindow win=xmit_table.get(sender);
if(win != null) {
if(local_addr.equals(sender)) {
win.setHighestDelivered(highest_delivered_seqno);
continue; // don't destroy my own window
}
xmit_table.remove(sender);
win.destroy(); // stops retransmission
}
win=createNakReceiverWindow(sender, highest_delivered_seqno, low_seqno);
xmit_table.put(sender, win);
}
sb.append("\n").append("resulting digest: " + getDigest());
digest_history.add(sb.toString());
if(log.isDebugEnabled())
log.debug(sb.toString());
}
/**
* Sets or merges the digest. If there is no entry for a given member in xmit_table, create a new NakReceiverWindow.
* Else skip the existing entry, unless it is a merge. In this case, skip the existing entry if its seqno is
* greater than or equal to the one in the digest, or reset the window and create a new one if not.
* @param digest The digest
* @param merge Whether to merge the new digest with our own, or not
*/
private void setDigest(Digest digest, boolean merge) {
if(digest == null)
return;
StringBuilder sb=new StringBuilder(merge? "\n[mergeDigest()]\n" : "\n[setDigest()]\n");
sb.append("existing digest: " + getDigest()).append("\nnew digest: " + digest);
boolean set_own_seqno=false;
for(Map.Entry<Address, Digest.Entry> entry: digest.getSenders().entrySet()) {
Address sender=entry.getKey();
Digest.Entry val=entry.getValue();
if(sender == null || val == null)
continue;
long highest_delivered_seqno=val.getHighestDeliveredSeqno();
long low_seqno=val.getLow();
NakReceiverWindow win=xmit_table.get(sender);
if(win != null) {
// We only reset the window if its seqno is lower than the seqno shipped with the digest. Also, we
// don't reset our own window (https://jira.jboss.org/jira/browse/JGRP-948, comment 20/Apr/09 03:39 AM)
if(!merge
|| (local_addr != null && local_addr.equals(sender)) // never overwrite our own entry
|| win.getHighestDelivered() >= highest_delivered_seqno) // my seqno is >= digest's seqno for sender
continue;
xmit_table.remove(sender);
win.destroy(); // stops retransmission
if(sender.equals(local_addr)) { // Adjust the seqno: https://jira.jboss.org/browse/JGRP-1251
seqno_lock.lock();
try {
seqno=highest_delivered_seqno;
set_own_seqno=true;
}
finally {
seqno_lock.unlock();
}
}
}
win=createNakReceiverWindow(sender, highest_delivered_seqno, low_seqno);
xmit_table.put(sender, win);
}
sb.append("\n").append("resulting digest: " + getDigest());
if(set_own_seqno)
sb.append("\nnew seqno for " + local_addr + ": " + seqno);
digest_history.add(sb.toString());
if(log.isDebugEnabled())
log.debug(sb.toString());
}
private NakReceiverWindow createNakReceiverWindow(Address sender, long initial_seqno, long lowest_seqno) {
NakReceiverWindow win=new NakReceiverWindow(sender, this, initial_seqno, lowest_seqno, timer, use_range_based_retransmitter,
xmit_table_num_rows, xmit_table_msgs_per_row,
xmit_table_resize_factor, xmit_table_max_compaction_time, false);
if(use_stats_for_retransmission)
win.setRetransmitTimeouts(new ActualInterval(sender));
else if(exponential_backoff > 0)
win.setRetransmitTimeouts(new ExponentialInterval(exponential_backoff));
else
win.setRetransmitTimeouts(new StaticInterval(retransmit_timeouts));
if(stats)
win.setListener(this);
return win;
}
/**
* Garbage collect messages that have been seen by all members. Update sent_msgs: for the sender P in the digest
* which is equal to the local address, garbage collect all messages <= seqno at digest[P]. Update xmit_table:
* for each sender P in the digest and its highest seqno seen SEQ, garbage collect all delivered_msgs in the
* NakReceiverWindow corresponding to P which are <= seqno at digest[P].
*/
private void stable(Digest digest) {
NakReceiverWindow recv_win;
long my_highest_rcvd; // highest seqno received in my digest for a sender P
long stability_highest_rcvd; // highest seqno received in the stability vector for a sender P
if(members == null || local_addr == null || digest == null) {
if(log.isWarnEnabled())
log.warn("members, local_addr or digest are null !");
return;
}
if(log.isTraceEnabled()) {
log.trace("received stable digest " + digest);
}
stability_msgs.add(digest);
Address sender;
Digest.Entry val;
long high_seqno_delivered, high_seqno_received;
for(Map.Entry<Address, Digest.Entry> entry: digest.getSenders().entrySet()) {
sender=entry.getKey();
if(sender == null)
continue;
val=entry.getValue();
high_seqno_delivered=val.getHighestDeliveredSeqno();
high_seqno_received=val.getHighestReceivedSeqno();
// check whether the last seqno received for a sender P in the stability vector is > last seqno
// received for P in my digest. if yes, request retransmission (see "Last Message Dropped" topic
// in DESIGN)
recv_win=xmit_table.get(sender);
if(recv_win != null) {
my_highest_rcvd=recv_win.getHighestReceived();
stability_highest_rcvd=high_seqno_received;
if(stability_highest_rcvd >= 0 && stability_highest_rcvd > my_highest_rcvd) {
if(log.isTraceEnabled()) {
log.trace("my_highest_rcvd (" + my_highest_rcvd + ") < stability_highest_rcvd (" +
stability_highest_rcvd + "): requesting retransmission of " +
sender + '#' + stability_highest_rcvd);
}
retransmit(stability_highest_rcvd, stability_highest_rcvd, sender);
}
}
high_seqno_delivered-=gc_lag;
if(high_seqno_delivered < 0) {
continue;
}
if(log.isTraceEnabled())
log.trace("deleting msgs <= " + high_seqno_delivered + " from " + sender);
// delete *delivered* msgs that are stable
if(recv_win != null) {
recv_win.stable(high_seqno_delivered); // delete all messages with seqnos <= seqno
}
}
}
/* ---------------------- Interface Retransmitter.RetransmitCommand ---------------------- */
/**
* Implementation of Retransmitter.RetransmitCommand. Called by retransmission thread when gap is detected.
*/
public void retransmit(long first_seqno, long last_seqno, Address sender) {
retransmit(first_seqno, last_seqno, sender, false);
}
protected void retransmit(long first_seqno, long last_seqno, final Address sender, boolean multicast_xmit_request) {
NakAckHeader hdr;
Message retransmit_msg;
Address dest=sender; // to whom do we send the XMIT request ?
if(multicast_xmit_request || this.use_mcast_xmit_req) {
dest=null;
}
else {
if(xmit_from_random_member && !local_addr.equals(sender)) {
Address random_member=(Address)Util.pickRandomElement(members);
if(random_member != null && !local_addr.equals(random_member)) {
dest=random_member;
if(log.isTraceEnabled())
log.trace("picked random member " + dest + " to send XMIT request to");
}
}
}
hdr=NakAckHeader.createXmitRequestHeader(first_seqno, last_seqno, sender);
retransmit_msg=new Message(dest, null, null);
retransmit_msg.setFlag(Message.OOB);
if(log.isTraceEnabled())
log.trace(local_addr + ": sending XMIT_REQ ([" + first_seqno + ", " + last_seqno + "]) to " + dest);
retransmit_msg.putHeader(this.id, hdr);
ConcurrentMap<Long,Long> tmp=xmit_stats.get(sender);
if(tmp == null) {
tmp=new ConcurrentHashMap<Long,Long>();
ConcurrentMap<Long,Long> tmp2=xmit_stats.putIfAbsent(sender, tmp);
if(tmp2 != null)
tmp=tmp2;
}
for(long seq=first_seqno; seq < last_seqno; seq++) {
tmp.putIfAbsent(seq, System.currentTimeMillis());
}
down_prot.down(new Event(Event.MSG, retransmit_msg));
if(stats) {
xmit_reqs_sent+=last_seqno - first_seqno +1;
updateStats(sent, sender, 1, 0, 0);
}
xmit_history.add(sender + ": " + first_seqno + "-" + last_seqno);
}
/* ------------------- End of Interface Retransmitter.RetransmitCommand -------------------- */
/* ----------------------- Interface NakReceiverWindow.Listener ---------------------- */
public void missingMessageReceived(long seqno, final Address original_sender) {
ConcurrentMap<Long,Long> tmp=xmit_stats.get(original_sender);
if(tmp != null) {
Long timestamp=tmp.remove(seqno);
if(timestamp != null) {
long diff=System.currentTimeMillis() - timestamp;
BoundedList<Long> list=xmit_times_history.get(original_sender);
if(list == null) {
list=new BoundedList<Long>(xmit_history_max_size);
BoundedList<Long> list2=xmit_times_history.putIfAbsent(original_sender, list);
if(list2 != null)
list=list2;
}
list.add(diff);
// compute the smoothed average for retransmission times for original_sender
// needs to be synchronized because we rely on the previous value for computation of the next value
synchronized(smoothed_avg_xmit_times) {
Double smoothed_avg=smoothed_avg_xmit_times.get(original_sender);
if(smoothed_avg == null)
smoothed_avg=INITIAL_SMOOTHED_AVG;
// the smoothed avg takes 90% of the previous value, 100% of the new value and averages them
// then, we add 10% to be on the safe side (an xmit value should rather err on the higher than lower side)
smoothed_avg=((smoothed_avg * WEIGHT) + diff) / 2;
smoothed_avg=smoothed_avg * (2 - WEIGHT);
smoothed_avg_xmit_times.put(original_sender, smoothed_avg);
}
}
}
if(stats) {
missing_msgs_received++;
updateStats(received, original_sender, 0, 0, 1);
}
}
/** Called when a message gap is detected */
public void messageGapDetected(long from, long to, Address src) {
;
}
/* ------------------- End of Interface NakReceiverWindow.Listener ------------------- */
private void reset() {
seqno_lock.lock();
try {
seqno=0;
}
finally {
seqno_lock.unlock();
}
for(NakReceiverWindow win: xmit_table.values()) {
win.destroy();
}
xmit_table.clear();
}
@ManagedOperation(description="TODO")
public String printMessages() {
StringBuilder ret=new StringBuilder(local_addr + ":\n");
for(Map.Entry<Address,NakReceiverWindow> entry: xmit_table.entrySet()) {
Address addr=entry.getKey();
NakReceiverWindow win=entry.getValue();
ret.append(addr).append(": ").append(win.toString()).append('\n');
}
return ret.toString();
}
@ManagedOperation(description="TODO")
public String printRetransmissionAvgs() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,BoundedList<Long>> entry: xmit_times_history.entrySet()) {
Address sender=entry.getKey();
BoundedList<Long> list=entry.getValue();
long tmp=0;
int i=0;
for(Long val: list) {
tmp+=val;
i++;
}
double avg=i > 0? tmp / i: -1;
sb.append(sender).append(": ").append(avg).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="TODO")
public String printSmoothedRetransmissionAvgs() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,Double> entry: smoothed_avg_xmit_times.entrySet()) {
sb.append(entry.getKey()).append(": ").append(entry.getValue()).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="TODO")
public String printRetransmissionTimes() {
StringBuilder sb=new StringBuilder();
for(Map.Entry<Address,BoundedList<Long>> entry: xmit_times_history.entrySet()) {
Address sender=entry.getKey();
BoundedList<Long> list=entry.getValue();
sb.append(sender).append(": ").append(list).append("\n");
}
return sb.toString();
}
@ManagedOperation(description="Prints the last N retransmission requests")
public String printXmitHistory() {
StringBuilder sb=new StringBuilder();
for(String req: xmit_history)
sb.append(req).append("\n");
return sb.toString();
}
@ManagedAttribute
public double getTotalAverageRetransmissionTime() {
long total=0;
int i=0;
for(BoundedList<Long> list: xmit_times_history.values()) {
for(Long val: list) {
total+=val;
i++;
}
}
return i > 0? total / i: -1;
}
@ManagedAttribute
public double getTotalAverageSmoothedRetransmissionTime() {
double total=0.0;
int cnt=0;
synchronized(smoothed_avg_xmit_times) {
for(Double val: smoothed_avg_xmit_times.values()) {
if(val != null) {
total+=val;
cnt++;
}
}
}
return cnt > 0? total / cnt : -1;
}
/** Returns the smoothed average retransmission time for a given sender */
public double getSmoothedAverageRetransmissionTime(Address sender) {
synchronized(smoothed_avg_xmit_times) {
Double retval=smoothed_avg_xmit_times.get(sender);
if(retval == null) {
retval=INITIAL_SMOOTHED_AVG;
smoothed_avg_xmit_times.put(sender, retval);
}
return retval;
}
}
// ProbeHandler interface
public Map<String, String> handleProbe(String... keys) {
Map<String,String> retval=new HashMap<String,String>();
for(String key: keys) {
if(key.equals("digest-history"))
retval.put(key, printDigestHistory());
if(key.equals("dump-digest"))
retval.put(key, "\n" + printMessages());
}
return retval;
}
// ProbeHandler interface
public String[] supportedKeys() {
return new String[]{"digest-history", "dump-digest"};
}
private class ActualInterval implements Interval {
private final Address sender;
public ActualInterval(Address sender) {
this.sender=sender;
}
public long next() {
return (long)getSmoothedAverageRetransmissionTime(sender);
}
public Interval copy() {
return this;
}
}
static class StatsEntry {
long xmit_reqs, xmit_rsps, missing_msgs_rcvd;
public String toString() {
StringBuilder sb=new StringBuilder();
sb.append(xmit_reqs).append(" xmit_reqs").append(", ").append(xmit_rsps).append(" xmit_rsps");
sb.append(", ").append(missing_msgs_rcvd).append(" missing msgs");
return sb.toString();
}
}
/* ----------------------------- End of Private Methods ------------------------------------ */
}