org.ka2ddo.yaac.core

Class AlohaTracker

java.lang.Object

org.ka2ddo.yaac.core.AlohaTracker

All Implemented Interfaces:

TrackerListener, GpsDataListener

public class AlohaTracker
extends java.lang.Object
implements TrackerListener, GpsDataListener

This class tracks the real-time addition and removal of stations from the data cache, and computes the Aloha circle for each open RF interface, based on current data and the algorithm defined by Bob Bruninga, WB4APR. It can therefore be queried efficiently when something else needs to know the circle radius.

Author:

Andrew Pavlin, KA2DDO

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_ALOHA_1200_CAPACITY Maximum number of typical APRS packets that can be transmitted at 1200 baud over a 30-minute period.

Method Summary

Modifier and Type	Method and Description
AlohaRanger[]	getAlohaRanges() Get the currently computed Aloha ranges for this station.
static AlohaTracker	getInstance() Get a reference to the singleton AlohaTracker.
double	getLastLatitude() Get the center latitude of the computed Aloha ranges.
double	getLastLongitude() Get the center longitude of the computed Aloha ranges.
void	gpsDataUpdated(GPSDistributor distributor, GpsFix currentFix, boolean isLocal, java.lang.String source) Called by the GPSDistributor when the GPS data has been updated.
static boolean	isDoAlohaForAprsIs() Report whether APRS-IS stations will be computed into an aloha circle.
static boolean	isDoRealAlohaModel() Indicate if the Aloha circle should be calculated based on actual traffic, not on WB4APR's old ideal traffic model.
void	messageAdded(StationState ss, int index, AX25Message msg) Called when a AX25Message is added to the history for a station in the tracker.
void	messageDeleted(StationState ss, int index, AX25Message msg) Called when a AX25Message is deleted from the history for a station in the tracker.
void	satDataUpdated(GPSDistributor distributor, SatelliteCatalog satCatalog, boolean isLocal, java.lang.String source) Called when the satellite constellation in use changes.
static void	setDoAlohaForAprsIs(boolean doAlohaForAprsIs) Specify whether APRS-IS stations will be computed into an aloha circle.
static void	setDoRealAlohaModel(boolean doRealAlohaModel) Specify if the Aloha circle should be calculated based on actual traffic, not on WB4APR's old ideal traffic model.
void	stationAdded(StationState ss, int index) Called when a new station is initially added to the tracker.
void	stationDeleted(StationState ss, int index) Called when an existing station is deleted from the tracker.
void	stationUpdated(StationState ss) Called when an existing station is updated with new information in the tracker.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_ALOHA_1200_CAPACITY

public static final int MAX_ALOHA_1200_CAPACITY

Maximum number of typical APRS packets that can be transmitted at 1200 baud over a 30-minute period.

See Also:

Constant Field Values

Method Detail

getInstance

public static AlohaTracker getInstance()

Get a reference to the singleton AlohaTracker.

Returns:

the AlohaTracker object

getAlohaRanges

public AlohaRanger[] getAlohaRanges()

Get the currently computed Aloha ranges for this station.

Returns:

array of per-RF-interface AlohaRanger objects

See Also:

getLastLatitude(), getLastLongitude()

getLastLatitude

public double getLastLatitude()

Get the center latitude of the computed Aloha ranges.

Returns:

double specifying the latitude (in decimal degrees) used for the last-fetched AlohaRanges

See Also:

getAlohaRanges()

getLastLongitude

public double getLastLongitude()

Get the center longitude of the computed Aloha ranges.

Returns:

double specifying the longitude (in decimal degrees) used for the last-fetched AlohaRanges

See Also:

getAlohaRanges()

isDoAlohaForAprsIs

public static boolean isDoAlohaForAprsIs()

Report whether APRS-IS stations will be computed into an aloha circle.

Returns:

boolean true if an aloha circle will be computed for Internet ports

setDoAlohaForAprsIs

public static void setDoAlohaForAprsIs(boolean doAlohaForAprsIs)

Specify whether APRS-IS stations will be computed into an aloha circle.

Parameters:

doAlohaForAprsIs - boolean true if an aloha circle should be computed for Internet ports

isDoRealAlohaModel

public static boolean isDoRealAlohaModel()

Indicate if the Aloha circle should be calculated based on actual traffic, not on WB4APR's old ideal traffic model. This may give different answers, based on collisions hiding higher actual traffic volume and weak or poorly modulated nearby stations that can't be heard by this station.

Returns:

boolean true if Aloha circle should be calculated on actual traffic, false if on ideal model

Since:

PROVIDER_API_VERSION == 57

setDoRealAlohaModel

public static void setDoRealAlohaModel(boolean doRealAlohaModel)

Specify if the Aloha circle should be calculated based on actual traffic, not on WB4APR's old ideal traffic model. This may give different answers, based on collisions hiding higher actual traffic volume and weak or poorly modulated nearby stations that can't be heard by this station.

Parameters:

doRealAlohaModel - boolean true if Aloha circle should be calculated on actual traffic, false if on ideal model

Since:

PROVIDER_API_VERSION == 57

gpsDataUpdated

public void gpsDataUpdated(GPSDistributor distributor,
                           GpsFix currentFix,
                           boolean isLocal,
                           java.lang.String source)

Called by the GPSDistributor when the GPS data has been updated.

Specified by:

gpsDataUpdated in interface GpsDataListener

Parameters:

distributor - instance of the GPSDistributor

currentFix - current position data reported by the local GPS

isLocal - boolean true if this is GPS data for the local station, false if for a remote GPS receiver

source - String name assigned to remote GPS receiver, or null if for the local receiver

satDataUpdated

public void satDataUpdated(GPSDistributor distributor,
                           SatelliteCatalog satCatalog,
                           boolean isLocal,
                           java.lang.String source)

Called when the satellite constellation in use changes. Meaningless to the AlohaTracker.

Specified by:

satDataUpdated in interface GpsDataListener

Parameters:

distributor - instance of the GPSDistributor

satCatalog - updated SatelliteCatalog instance

isLocal - boolean true if this is GPS data for the local station, false if for a remote GPS receiver

source - String name assigned to remote GPS receiver, or null if for the local receiver

stationAdded

public void stationAdded(StationState ss,
                         int index)

Called when a new station is initially added to the tracker.

Specified by:

stationAdded in interface TrackerListener

Parameters:

ss - StationState containing the station's information; the initial AX25Message will not yet be stored within the StationState object

index - zero-based integer sequence number for this station in the StationTracker

stationUpdated

public void stationUpdated(StationState ss)

Called when an existing station is updated with new information in the tracker.

Specified by:

stationUpdated in interface TrackerListener

Parameters:

ss - StationState containing the station's information; the new AX25Message will not yet be stored within the StationState object

stationDeleted

public void stationDeleted(StationState ss,
                           int index)

Called when an existing station is deleted from the tracker.

Specified by:

stationDeleted in interface TrackerListener

Parameters:

ss - StationState containing the station's information

index - zero-based integer sequence number for this station in the StationTracker

messageAdded

public void messageAdded(StationState ss,
                         int index,
                         AX25Message msg)

Called when a AX25Message is added to the history for a station in the tracker.

Specified by:

messageAdded in interface TrackerListener

Parameters:

ss - StationState containing the station's information

index - zero-based index of the message added to the StationState object

msg - APRS Message object being added to the tracker; note that non-APRS packets that can still be decoded (such as OpenTRAC) will also be passed here; AX25Frames that cannot be decoded will pass null here

messageDeleted

public void messageDeleted(StationState ss,
                           int index,
                           AX25Message msg)

Called when a AX25Message is deleted from the history for a station in the tracker.

Specified by:

messageDeleted in interface TrackerListener

Parameters:

ss - StationState containing the station's information; the AX25Message will already be removed from the StationState object

index - zero-based index of the message removed from the StationState object

msg - APRS Message object being removed from the tracker; note that non-APRS packets that can still be decoded (such as OpenTRAC) will also be passed here; AX25Frames that cannot be decoded will pass null here