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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.MBean;
import org.jgroups.annotations.ManagedAttribute;
import org.jgroups.annotations.Property;
import org.jgroups.stack.Protocol;
import org.jgroups.util.Average;
import org.jgroups.util.MessageBatch;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.function.Supplier;

/**
 * Protocol measuring latency between stacks. On {@link Protocol#down(org.jgroups.Event)}, a header is added to the
 * message with the ID of the PERF protocol and the start time is set in the header.
 * On {@link Protocol#up(org.jgroups.Event)}, the time difference is computed and a rolling average is updated in PERF.
 * Note that we can have several measurements by inserting PERF protocols with different IDs (Protocol.id) into the stack.
 * If PERF is used to measure latency between nodes running on different physical boxes, it is important that the clocks
 * are synchronized, or else latency cannot be computed correctly (may even be negative).
 * @author Bela Ban
 * @since  3.5
 */
@MBean(description="Measures latency between PERF instances")
public class PERF extends Protocol {
    protected Average avg;
    protected Address local_addr;

    @Property(description="Number of samples to maintain for rolling average")
    protected int     avg_size=20;

    @ManagedAttribute(description="Average latency in ns")
    public double latencyInNs() {return avg.getAverage();}

    @ManagedAttribute(description="Average latency in ms")
    public double latencyInMs() {return avg.getAverage() / 1000000.0;}

    public void init() throws Exception {
        super.init();
        avg=new Average();
    }

    public void resetStats() {
        super.resetStats();
        avg.clear();
    }

    public Object down(Event evt) {
        switch(evt.getType()) {
            case Event.SET_LOCAL_ADDRESS:
                local_addr=evt.getArg();
                break;
        }
        return down_prot.down(evt);
    }

    public Object down(Message msg) {
        msg.putHeader(id, new PerfHeader(System.nanoTime()));
        return down_prot.down(msg);
    }

    public Object up(Message msg) {
        PerfHeader hdr=msg.getHeader(id);
        if(hdr == null)
            log.error("%s: no perf header found", local_addr);
        else {
            long time=System.nanoTime() - hdr.start_time;
            if(time <= 0)
                log.error("%d: time is <= 0", time);
            else
                avg.add(time);
        }
        return up_prot.up(msg);
    }

    public void up(MessageBatch batch) {
        for(Message msg: batch) {
            PerfHeader hdr=msg.getHeader(id);
            if(hdr == null)
                log.error("%s: no perf header found", local_addr);
            else {
                long time=System.nanoTime() - hdr.start_time;
                if(time <= 0)
                    log.error("%d: time is <= 0", time);
                else
                    avg.add(time);
            }
        }

        super.up(batch);
    }

    protected static class PerfHeader extends Header {
        protected long start_time; // in ns

        public PerfHeader() {
        }

        public PerfHeader(long start_time) {
            this.start_time=start_time;
        }
        public short getMagicId() {return 84;}
        public Supplier create() {
            return PerfHeader::new;
        }

        @Override
        public int serializedSize() {
            return Global.LONG_SIZE;
        }

        @Override
        public void writeTo(DataOutput out) throws IOException {
            out.writeLong(start_time);
        }

        @Override
        public void readFrom(DataInput in) throws IOException {
            start_time=in.readLong();
        }
    }
}