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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.annotations.*;
import org.jgroups.conf.AttributeType;
import org.jgroups.stack.Protocol;
import org.jgroups.util.*;
import java.io.DataInput;
import java.io.DataOutput;
import java.util.*;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.Predicate;
import java.util.function.Supplier;
/**
* @author Bela Ban
* @since 5.0.0
*/
@MBean(description="Heartbeat-based failure detection protocol")
public abstract class FailureDetection extends Protocol {
@Property(description="Timeout after which a node is suspected if neither a heartbeat nor data have been received from it",
type=AttributeType.TIME)
protected long timeout=40000;
@Property(description="Interval at which a HEARTBEAT is sent to the cluster",type=AttributeType.TIME)
protected long interval=8000;
@ManagedAttribute(description="Number of heartbeats sent",type=AttributeType.SCALAR)
protected int num_heartbeats_sent;
@ManagedAttribute(description="Number of heartbeats received",type=AttributeType.SCALAR)
protected int num_heartbeats_received;
@ManagedAttribute(description="Number of suspected events received",type=AttributeType.SCALAR)
protected int num_suspect_events;
@ManagedAttribute(description="Shows whether there are currently any suspected members")
protected volatile boolean has_suspected_mbrs;
protected final List members=new ArrayList<>();
protected final Set suspected_mbrs=new HashSet<>();
protected final BoundedList> suspect_history=new BoundedList<>(20);
protected final Lock lock=new ReentrantLock();
protected TimeScheduler timer;
protected final Predicate HAS_HEADER=msg -> msg != null && msg.getHeader(this.id) != null;
// task which multicasts HEARTBEAT message after 'interval' ms
@GuardedBy("lock") protected Future heartbeat_sender;
// task which checks for members exceeding timeout and suspects them
@GuardedBy("lock") protected Future timeout_checker;
protected final AtomicBoolean mcast_sent=new AtomicBoolean(false);
protected abstract Map getTimestamps();
protected abstract long getTimeoutCheckInterval();
protected abstract String getTimeoutCheckerInfo();
protected abstract void update(Address sender, boolean log_msg, boolean skip_if_exists);
protected abstract boolean needsToBeSuspected(Address mbr, T value);
public long getTimeout() {return timeout;}
public T setTimeout(long t) {this.timeout=t; return (T)this;}
public long getInterval() {return interval;}
public T setInterval(long i) {this.interval=i; return (T)this;}
public int getHeartbeatsSent() {return num_heartbeats_sent;}
public int getHeartbeatsReceived() {return num_heartbeats_received;}
public int getSuspectEventsSent() {return num_suspect_events;}
protected void retainKeys(List mbrs) {getTimestamps().keySet().retainAll(mbrs);}
protected Runnable createTimeoutChecker() {return new TimeoutChecker();}
@ManagedAttribute(description="The members of the cluster")
public String getMembers() {return Util.printListWithDelimiter(members, ",");}
@ManagedAttribute(description="Currently suspected members")
public synchronized String getSuspectedMembers() {return suspected_mbrs.toString();}
@ManagedAttribute(description="Are heartbeat tasks running")
public boolean isRunning() {
lock.lock();
try{
return isTimeoutCheckerRunning() && isHeartbeatSenderRunning();
}
finally{
lock.unlock();
}
}
@ManagedAttribute(description="Is the timeout checker task running")
public boolean isTimeoutCheckerRunning() {
return timeout_checker != null && !timeout_checker.isDone();
}
@ManagedAttribute(description="Is the heartbeat sender task running")
public boolean isHeartbeatSenderRunning() {
return heartbeat_sender != null && !heartbeat_sender.isDone();
}
@ManagedOperation(description="Resumes checking for crashed members")
public void startFailureDetection() {
startTimeoutChecker();
}
@ManagedOperation(description="Stops checking for crashed members")
public void stopFailureDetection() {
stopTimeoutChecker();
}
@ManagedOperation(description="Prints suspect history")
public String printSuspectHistory() {
StringBuilder sb=new StringBuilder();
for(Tuple tmp: suspect_history) {
sb.append(Util.utcEpoch(tmp.getVal2())).append(": ").append(tmp.getVal1()).append("\n");
}
return sb.toString();
}
public void resetStats() {
num_heartbeats_sent=num_heartbeats_received=num_suspect_events=0;
suspect_history.clear();
}
public void init() throws Exception {
timer=getTransport().getTimer();
if(timer == null)
throw new Exception("timer not set");
suspected_mbrs.clear();
has_suspected_mbrs=false;
}
public synchronized void stop() {
stopHeartbeatSender();
stopTimeoutChecker();
suspected_mbrs.clear();
has_suspected_mbrs=false;
}
public Object down(Event evt) {
switch(evt.getType()) {
case Event.VIEW_CHANGE:
down_prot.down(evt);
View v=evt.getArg();
handleViewChange(v);
return null;
case Event.UNSUSPECT:
Address mbr=evt.getArg();
unsuspect(mbr);
update(mbr, false, false);
break;
}
return down_prot.down(evt);
}
public Object down(Message msg) {
if(msg.getDest() == null)
mcast_sent.compareAndSet(false, true);
return down_prot.down(msg);
}
public Object up(Message msg) {
Address sender=msg.getSrc();
Header hdr=msg.getHeader(this.id);
if(hdr != null) {
update(sender, true, false); // updates the heartbeat entry for 'sender'
num_heartbeats_received++;
unsuspect(sender);
return null; // consume heartbeat message, do not pass to the layer above
}
update(sender, false, false);
if(has_suspected_mbrs)
unsuspect(sender);
return up_prot.up(msg); // pass up to the layer above us
}
public void up(MessageBatch batch) {
int old_size=batch.size();
batch.removeIf(HAS_HEADER, true);
int removed=old_size - batch.size();
update(batch.sender(), removed > 0, false);
if(removed > 0)
num_heartbeats_received+=removed;
if(has_suspected_mbrs)
unsuspect(batch.sender());
if(!batch.isEmpty())
up_prot.up(batch);
}
protected void handleViewChange(View v) {
List mbrs=v.getMembers();
synchronized(this) {
members.clear();
members.addAll(mbrs);
if(suspected_mbrs.retainAll(mbrs))
has_suspected_mbrs=!suspected_mbrs.isEmpty();
retainKeys(mbrs);
}
mbrs.forEach(m -> update(m, false, true));
if(mbrs.size() > 1) {
startHeartbeatSender();
startTimeoutChecker();
}
else {
stopHeartbeatSender();
stopTimeoutChecker();
}
}
protected void suspect(List suspects) {
if(suspects == null || suspects.isEmpty())
return;
num_suspect_events+=suspects.size();
final List eligible_mbrs;
synchronized(this) {
for(Address suspect: suspects) {
suspect_history.add(new Tuple<>(suspect, System.currentTimeMillis())); // need wall clock time
suspected_mbrs.add(suspect);
}
eligible_mbrs=new ArrayList<>(members);
eligible_mbrs.removeAll(suspected_mbrs);
has_suspected_mbrs=!suspected_mbrs.isEmpty();
}
// Check if we're coord, then send up the stack
if(local_addr != null && !eligible_mbrs.isEmpty() && local_addr.equals(eligible_mbrs.get(0))) {
log.debug("%s: suspecting %s", local_addr, suspects);
up_prot.up(new Event(Event.SUSPECT, suspects));
down_prot.down(new Event(Event.SUSPECT, suspects));
}
}
/**
* Removes mbr from suspected_mbrs and sends a UNSUSPECT event up and down the stack
* @param mbr The member to be unsuspected
* @return True if the member was removed from suspected_mbrs, otherwise false
*/
protected boolean unsuspect(Address mbr) {
if(mbr == null) return false;
boolean do_unsuspect;
synchronized(this) {
do_unsuspect=!suspected_mbrs.isEmpty() && suspected_mbrs.remove(mbr);
if(do_unsuspect) {
has_suspected_mbrs=!suspected_mbrs.isEmpty();
log.debug("%s: unsuspecting %s", local_addr, mbr);
}
}
if(do_unsuspect) {
up_prot.up(new Event(Event.UNSUSPECT, mbr));
down_prot.down(new Event(Event.UNSUSPECT, mbr));
}
return do_unsuspect;
}
protected void startHeartbeatSender() {
lock.lock();
try {
if(!isHeartbeatSenderRunning()) {
heartbeat_sender=timer.scheduleWithFixedDelay(new HeartbeatSender(this), 0, interval, TimeUnit.MILLISECONDS,
getTransport() instanceof TCP);
}
}
finally {
lock.unlock();
}
}
protected void stopHeartbeatSender() {
lock.lock();
try {
if(heartbeat_sender != null) {
heartbeat_sender.cancel(true);
heartbeat_sender=null;
}
}
finally {
lock.unlock();
}
}
protected void startTimeoutChecker() {
lock.lock();
try {
if(!isTimeoutCheckerRunning()) {
timeout_checker=timer.scheduleWithFixedDelay(createTimeoutChecker(), getTimeoutCheckInterval(),
getTimeoutCheckInterval(), TimeUnit.MILLISECONDS, false);
}
}
finally {
lock.unlock();
}
}
protected void stopTimeoutChecker() {
lock.lock();
try {
if(timeout_checker != null) {
timeout_checker.cancel(true);
timeout_checker=null;
}
}
finally {
lock.unlock();
}
}
public static class HeartbeatHeader extends Header {
public HeartbeatHeader() {}
public short getMagicId() {return 62;}
public Supplier create() {return HeartbeatHeader::new;}
public String toString() {return "heartbeat";}
@Override public int serializedSize() {return 0;}
@Override public void writeTo(DataOutput out) {}
@Override public void readFrom(DataInput in) {}
}
/** Class which periodically multicasts a HEARTBEAT message to the cluster */
class HeartbeatSender implements Runnable {
protected final FailureDetection enclosing;
HeartbeatSender(FailureDetection enclosing) {
this.enclosing=enclosing;
}
public void run() {
if(mcast_sent.compareAndSet(true, false))
; // suppress sending of heartbeat
else {
Message heartbeat=new EmptyMessage().setFlag(Message.TransientFlag.DONT_LOOPBACK)
.putHeader(id, new HeartbeatHeader());
down_prot.down(heartbeat);
num_heartbeats_sent++;
log.trace("%s: sent heartbeat", local_addr);
}
}
public String toString() {
return String.format("%s: %s", enclosing.getClass().getSimpleName(), getClass().getSimpleName());
}
}
class TimeoutChecker implements Runnable {
public void run() {
synchronized(this) {
retainKeys(members); // remove all non-members (// https://issues.redhat.com/browse/JGRP-2387)
}
List suspects=new LinkedList<>();
for(Iterator> it=getTimestamps().entrySet().iterator(); it.hasNext();) {
Map.Entry entry=it.next();
Address key=entry.getKey();
Object val=entry.getValue();
if(val == null) {
it.remove();
continue;
}
if(needsToBeSuspected(key, val))
suspects.add(key);
}
if(!suspects.isEmpty())
suspect(suspects);
}
public String toString() {return getTimeoutCheckerInfo();}
}
}