Class Transport

java.lang.Object
  Transport

public class Transport

extends java.lang.Object

   
 This conveys the header for reliable message transfer.
 This is carried in the payload of a Packet, and in turn the data being
 transferred is carried in the payload of the Transport packet.
 

Field Summary

static int	ACK
static int	DATA
static int	FIN
static int	HEADER_SIZE
static int	MAX_PACKET_SIZE
static int	MAX_PAYLOAD_SIZE
static int	MAX_PORT_NUM
static int	SYN

Constructor Summary

Transport(int srcPort, int destPort, int type, int window, int seqNum, byte[] payload)
Constructing a new transport packet.

Method Summary

int	getDestPort()
byte[]	getPayload()
int	getSeqNum()
int	getSrcPort()
int	getType()
int	getWindow()
byte[]	pack() Convert the Transport packet object into a byte array for sending over the wire.
static Transport	unpack(byte[] packet) Unpacks a byte array to create a Transport object Assumes the array has been formatted using pack method in Transport

Methods inherited from class java.lang.Object

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

Field Detail

MAX_PACKET_SIZE

public static final int MAX_PACKET_SIZE

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Constant Field Values

HEADER_SIZE

public static final int HEADER_SIZE

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Constant Field Values

MAX_PAYLOAD_SIZE

public static final int MAX_PAYLOAD_SIZE

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Constant Field Values

MAX_PORT_NUM

public static final int MAX_PORT_NUM

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Constant Field Values

SYN

public static final int SYN

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Constant Field Values

ACK

public static final int ACK

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Constant Field Values

FIN

public static final int FIN

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Constant Field Values

DATA

public static final int DATA

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Constant Field Values

Constructor Detail

Transport

public Transport(int srcPort,
                 int destPort,
                 int type,
                 int window,
                 int seqNum,
                 byte[] payload)
          throws java.lang.IllegalArgumentException

Constructing a new transport packet.

Parameters:

srcPort - The source port

destPort - The destination port

type - The type of packet. Either SYN, ACK, FIN, or DATA

window - The window size

seqNum - The sequence number of the packet

payload - The payload of the packet.

Method Detail

getSrcPort

public int getSrcPort()

Returns:

The source port

getDestPort

public int getDestPort()

Returns:

The destination port

getType

public int getType()

Returns:

The type of the packet

getWindow

public int getWindow()

Returns:

The window size

getSeqNum

public int getSeqNum()

Returns:

The sequence number

getPayload

public byte[] getPayload()

Returns:

The payload

pack

public byte[] pack()

Convert the Transport packet object into a byte array for sending over the wire. Format: source port = 1 byte destination port = 1 byte type = 1 byte window size = 4 bytes sequence number = 4 bytes packet length = 1 byte payload <= MAX_PAYLOAD_SIZE bytes

Returns:

A byte[] for transporting over the wire. Null if failed to pack for some reason

unpack

public static Transport unpack(byte[] packet)

Unpacks a byte array to create a Transport object Assumes the array has been formatted using pack method in Transport

Parameters:

packet - String representation of the transport packet

Returns:

Transport object created or null if the byte[] representation was corrupted