com.threerings.presents.client
Class DeltaCalculator

java.lang.Object
  com.threerings.presents.client.DeltaCalculator

public class DeltaCalculator
extends Object

Used to compute the client/server time delta, attempting to account for the network delay experienced when the server sends its current time to the client.

Field Summary

protected long[]	_deltas Client/server time delta estimates.
protected int	_iter The number of ping/pong iterations we've made.
protected PingRequest	_ping A reference to the most recently sent ping which we use to obtain the appropriate send stamp when we get the corresponding receive stamp.
protected static int	CLOCK_SYNC_PING_COUNT The number of times we PING during clock sync to try to smooth out network jiggling.

Constructor Summary

DeltaCalculator()
Constructs a delta calculator which is used to calculate the time delta between the client and server, accounting reasonably well for the delay introduced by sending a timestamp over the network from the server to the client.

Method Summary

long	getTimeDelta() Returns the best estimate client/server time-delta.
boolean	gotPong(PongResponse pong) Must be called when the pong response arrives back from the server.
boolean	isDone() Returns true if this calculator has enough data to compute a time delta estimate.
void	sentPing(PingRequest ping) Must be called when a ping message is sent to the server.
boolean	shouldSendPing() Should we send another ping?

Methods inherited from class java.lang.Object

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

Field Detail

_iter

protected int _iter

The number of ping/pong iterations we've made.

_deltas

protected long[] _deltas

Client/server time delta estimates.

_ping

protected PingRequest _ping

A reference to the most recently sent ping which we use to obtain the appropriate send stamp when we get the corresponding receive stamp.

CLOCK_SYNC_PING_COUNT

protected static final int CLOCK_SYNC_PING_COUNT

The number of times we PING during clock sync to try to smooth out network jiggling.

See Also:

Constant Field Values

Constructor Detail

DeltaCalculator

public DeltaCalculator()

Constructs a delta calculator which is used to calculate the time delta between the client and server, accounting reasonably well for the delay introduced by sending a timestamp over the network from the server to the client.

Method Detail

shouldSendPing

public boolean shouldSendPing()

Should we send another ping?

sentPing

public void sentPing(PingRequest ping)

Must be called when a ping message is sent to the server.

gotPong

public boolean gotPong(PongResponse pong)

Must be called when the pong response arrives back from the server.

Returns:

true if we've iterated sufficiently many times to establish a stable time delta estimate.

getTimeDelta

public long getTimeDelta()

Returns the best estimate client/server time-delta.

isDone

public boolean isDone()

Returns true if this calculator has enough data to compute a time delta estimate. Stick a fork in it!