dk.itu.haas.GPS.Garmin
Class GarminPacket

java.lang.Object
  |
  +--dk.itu.haas.GPS.Garmin.GarminPacket

Direct Known Subclasses:

PositionDataPacket, ProductDataPacket, ProtocolDataPacket, PVTDataPacket, RecordsPacket, TimeDataPacket, WaypointDataPacket

public class GarminPacket

extends java.lang.Object

A class that encapsulates the basic functionality of a packet.

Field Summary

static int	Cmnd_Abort_Transfer Abort current transfer.
static int	Cmnd_Start_Pvt_Data Start transmitting PVT (Position, velocity, time) Data.
static int	Cmnd_Stop_Pvt_Data Stop transmitting PVT (Position, velocity, time) Data.
static int	Cmnd_Transfer_Alm Transfer almanac.
static int	Cmnd_Transfer_Posn Transfer position.
static int	Cmnd_Transfer_Prx Transfer proximity waypoints.
static int	Cmnd_Transfer_Rte Transfer routes.
static int	Cmnd_Transfer_Time Transfer time.
static int	Cmnd_Transfer_Trk Transfer track log.
static int	Cmnd_Transfer_Wpt Transfer waypoints.
static int	Cmnd_Turn_Off_Pwr Turn off power.
static int	DLE Data link escape.
static int	ETX End of text.
protected int[]	packet The packet in byte-form.
static int	Pid_Ack_Byte
static int	Pid_Command_Data
static int	Pid_Date_Time_Data
static int	Pid_Nak_Byte
static int	Pid_Position_Data
static int	Pid_Product_Data
static int	Pid_Product_Rqst
static int	Pid_Protocol_Array
static int	Pid_Pvt_Data
static int	Pid_Records
static int	Pid_Wpt_Data
static int	Pid_Xfer_Cmplt

Constructor Summary

GarminPacket(int[] p)
Creates a new GarminPacket with the contents of p.

GarminPacket(int[] p, boolean calcChecksum)
Creates a new GarminPacket with the contents of p.

Method Summary

int	calcChecksum() Calculates the checksum for the packet.
static GarminPacket	createBasicPacket(int type, int[] data) This method is capable of making the data-packets from L000 (basic link protocol).
static GarminPacket	createCommandPacket(int type) This is a factory-method capable of creating instances the commandpackets from A010.
protected int	getByte(int i) Returns the packet-byte at position i.
int	getDataLength() Returns the amount of bytes in the data-field of this packet.
int	getID() Returns the ID (ie. type) of the packet.
protected int	getLength() Returns the length of the entire packet in bytes.
protected int[]	getPacket() Returns the packet in it's original byte-form.
java.lang.String	getRawPacket() Debug-method.
static java.lang.String	idToString(int id) Method that translates a packet-id into a human-readable string.
int	isLegal() Checks if the packet is valid with regards to header, footer,data-field-length and checksum.
protected short	readByte(int packet_index) Method that reads a Garmin-byte in the packet and returns it as a short.
protected double	readDouble(int packet_index) Method that reads a Garmin-double in the packet and returns it as a double.
protected float	readFloat(int packet_index) Method that reads a Garmin-float in the packet and returns it as a float.
protected int	readLong(int packet_index) Method that reads a Garmin-long in the packet and returns it as an int.
protected java.lang.String	readNullTerminatedString(int packet_index) Method that reads a null-terminated string.
protected int	readWord(int packet_index) Method that reads a Garmin-word in the packet and returns it as an int.
java.lang.String	toString() Returns a human-readable string with information to the packet's contents.

Methods inherited from class java.lang.Object

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

Field Detail

Pid_Ack_Byte

public static final int Pid_Ack_Byte

See Also:

Constant Field Values

Pid_Nak_Byte

public static final int Pid_Nak_Byte

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Constant Field Values

Pid_Protocol_Array

public static final int Pid_Protocol_Array

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Constant Field Values

Pid_Product_Rqst

public static final int Pid_Product_Rqst

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Constant Field Values

Pid_Product_Data

public static final int Pid_Product_Data

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Constant Field Values

Pid_Command_Data

public static final int Pid_Command_Data

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Constant Field Values

Pid_Xfer_Cmplt

public static final int Pid_Xfer_Cmplt

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Constant Field Values

Pid_Date_Time_Data

public static final int Pid_Date_Time_Data

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Constant Field Values

Pid_Position_Data

public static final int Pid_Position_Data

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Constant Field Values

Pid_Records

public static final int Pid_Records

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Constant Field Values

Pid_Wpt_Data

public static final int Pid_Wpt_Data

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Constant Field Values

Pid_Pvt_Data

public static final int Pid_Pvt_Data

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Constant Field Values

Cmnd_Abort_Transfer

public static final int Cmnd_Abort_Transfer

Abort current transfer.

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Constant Field Values

Cmnd_Transfer_Alm

public static final int Cmnd_Transfer_Alm

Transfer almanac.

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Constant Field Values

Cmnd_Transfer_Posn

public static final int Cmnd_Transfer_Posn

Transfer position.

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Constant Field Values

Cmnd_Transfer_Prx

public static final int Cmnd_Transfer_Prx

Transfer proximity waypoints.

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Constant Field Values

Cmnd_Transfer_Rte

public static final int Cmnd_Transfer_Rte

Transfer routes.

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Constant Field Values

Cmnd_Transfer_Time

public static final int Cmnd_Transfer_Time

Transfer time.

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Constant Field Values

Cmnd_Transfer_Trk

public static final int Cmnd_Transfer_Trk

Transfer track log.

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Constant Field Values

Cmnd_Transfer_Wpt

public static final int Cmnd_Transfer_Wpt

Transfer waypoints.

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Constant Field Values

Cmnd_Turn_Off_Pwr

public static final int Cmnd_Turn_Off_Pwr

Turn off power.

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Constant Field Values

Cmnd_Start_Pvt_Data

public static final int Cmnd_Start_Pvt_Data

Start transmitting PVT (Position, velocity, time) Data.

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Constant Field Values

Cmnd_Stop_Pvt_Data

public static final int Cmnd_Stop_Pvt_Data

Stop transmitting PVT (Position, velocity, time) Data.

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Constant Field Values

DLE

public static final int DLE

Data link escape. Packet boundary.

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Constant Field Values

ETX

public static final int ETX

End of text. Packet boundary.

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Constant Field Values

packet

protected int[] packet

The packet in byte-form. It is required that the array-length is trimmed to the size of the packet.

Constructor Detail

GarminPacket

public GarminPacket(int[] p)

Creates a new GarminPacket with the contents of p. Throws InvalidPacketException if packet is malformed.

GarminPacket

public GarminPacket(int[] p,
                    boolean calcChecksum)

Creates a new GarminPacket with the contents of p. if calcChecksum is true, the packet will have it's checksum recalculated. Throws InvalidPacketException if packet is malformed.

Method Detail

calcChecksum

public int calcChecksum()

Calculates the checksum for the packet. Does not insert it into the correct position of the int[] packet array.
The method assumes that the packet is a valid Garmin-packet with all values containing their final values.

getID

public int getID()

Returns the ID (ie. type) of the packet.

getDataLength

public int getDataLength()

Returns the amount of bytes in the data-field of this packet.

getByte

protected int getByte(int i)

Returns the packet-byte at position i.

getPacket

protected int[] getPacket()

Returns the packet in it's original byte-form.
Note: The array returned is a clone of the array contained in the class. Changing the values in the array will not affect the contents of the class.

getLength

protected int getLength()

Returns the length of the entire packet in bytes.

readWord

protected int readWord(int packet_index)

Method that reads a Garmin-word in the packet and returns it as an int. This method can be used to read both int and word from a Garmin-packet.

readLong

protected int readLong(int packet_index)

Method that reads a Garmin-long in the packet and returns it as an int.

readNullTerminatedString

protected java.lang.String readNullTerminatedString(int packet_index)

Method that reads a null-terminated string.

idToString

public static java.lang.String idToString(int id)

Method that translates a packet-id into a human-readable string.

getRawPacket

public java.lang.String getRawPacket()

Debug-method. Returns a String-representation of the bytes in the packet.

createCommandPacket

public static GarminPacket createCommandPacket(int type)

This is a factory-method capable of creating instances the commandpackets from A010. (Device Command Protocol 1) returns null if it can't make a packet from the argument supplied.
type can be one of the following constants:

• Cmnd_Turn_Off_Pwr
• Cmnd_Transfer_Posn
• Cmnd_Transfer_Time
• Cmnd_Abort_Transfer
• Cmnd_Transfer_Alm
• Cmnd_Transfer_Prx
• Cmnd_Transfer_Rte
• Cmnd_Transfer_Trk
• Cmnd_Transfer_Wpt
• Cmnd_Start_Pvt_Data
• Cmnd_Stop_Pvt_Data

createBasicPacket

public static GarminPacket createBasicPacket(int type,
                                             int[] data)

This method is capable of making the data-packets from L000 (basic link protocol).
type can be one of the following constants:

• Pid_Ack_Byte
• Pid_Nak_Byte
• Pid_Protocol_Array
• Pid_Product_Rqst
• Pid_Product_Data

The argument data is an array of int that will be put in the data-field of the packet.

isLegal

public int isLegal()

Checks if the packet is valid with regards to header, footer,data-field-length and checksum. Returns the index of the illegal byte. If packet is ok, -1 is returned.

readByte

protected short readByte(int packet_index)

Method that reads a Garmin-byte in the packet and returns it as a short.

readDouble

protected double readDouble(int packet_index)

Method that reads a Garmin-double in the packet and returns it as a double.

toString

public java.lang.String toString()

Returns a human-readable string with information to the packet's contents.

Overrides:

toString in class java.lang.Object

readFloat

protected float readFloat(int packet_index)

Method that reads a Garmin-float in the packet and returns it as a float.