net.tomp2p.peers

Class RTT

java.lang.Object

net.tomp2p.peers.RTT

public class RTT
extends Object

Class responsible for measuring and storing a Round Trip Time (RTT) This is used to compare peers with similar distance when routing.

Author:

Sebastian Stephan

Constructor Summary

Constructors

Constructor and Description
RTT()
RTT(long rtt, boolean isUDP) Create RTT object with some given RTT, and a flag if the time was measured on a UDP exchange.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	beginTimeMeasurement(boolean isUDP) Begin counting the time.
long	getRtt() Get round-trip-time in milliseconds.
long	getStartMeasurementTimestamp()
boolean	isEstimated() Returns if the RTT measured is an estimate for some other peer
boolean	isUDP()
RTT	setEstimated() Marks this RTT object as an estimate
boolean	stopTimeMeasurement() Stop the time measurement and calculate the rtt BeginTimeMeasurement must have been called before Can only be called once
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

RTT

public RTT()

RTT

public RTT(long rtt,
   boolean isUDP)

Create RTT object with some given RTT, and a flag if the time was measured on a UDP exchange.

Parameters:

rtt - The rtt to be set in milliseconds

isUDP - True if this was an UDP exchange, set false if it was a TCP exchange.

Method Detail

beginTimeMeasurement

public boolean beginTimeMeasurement(boolean isUDP)

Begin counting the time. Can be called multiple times, as long as it has not yet been stopped

Returns:

True if time measurement has been started, False otherwise

stopTimeMeasurement

public boolean stopTimeMeasurement()

Stop the time measurement and calculate the rtt BeginTimeMeasurement must have been called before Can only be called once

Returns:

True if RTT was set, False otherwise

getStartMeasurementTimestamp

public long getStartMeasurementTimestamp()

getRtt

public long getRtt()

Get round-trip-time in milliseconds. If the RTT was calculated by TCP, the value will be scaled down by TCP_SCALE_DOWN_FACTOR

Returns:

round-trip-time in milliseconds, -1 if no measurement done.

isUDP

public boolean isUDP()

isEstimated

public boolean isEstimated()

Returns if the RTT measured is an estimate for some other peer

Returns:

True if it is an estimate, false otherwise

setEstimated

public RTT setEstimated()

Marks this RTT object as an estimate

Returns:

The RTT object

toString

public String toString()

Overrides:

toString in class Object