Class Packet

java.lang.Object
  Packet

public class Packet
extends java.lang.Object

   
 Packet defines the Fishnet packet headers and some constants.
 

Field Summary

static int	BROADCAST_ADDRESS
static int	HEADER_SIZE
static int	MAX_ADDRESS
static int	MAX_PACKET_SIZE
static int	MAX_PAYLOAD_SIZE
static int	MAX_TTL

Constructor Summary

Packet(int dest, int src, int ttl, int protocol, int seq, byte[] payload)
Constructing a new packet.

Method Summary

int	getDest()
byte[]	getPayload()
int	getProtocol()
int	getSeq()
int	getSrc()
int	getTTL()
boolean	isValid() Tests if this Packet is valid or not
byte[]	pack() Convert the Packet object into a byte array for sending over the wire.
void	setTTL(int ttl) Sets the TTL of this packet
java.lang.String	toString() Provides a string representation of the packet.
static Packet	unpack(byte[] packedPacket) Unpacks a byte array to create a Packet object Assumes the array has been formatted using pack method in Packet
static boolean	validAddress(int addr) Tests if the address is a valid one

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

BROADCAST_ADDRESS

public static final int BROADCAST_ADDRESS

See Also:

Constant Field Values

MAX_ADDRESS

public static final int MAX_ADDRESS

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Constant Field Values

HEADER_SIZE

public static final int HEADER_SIZE

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Constant Field Values

MAX_PACKET_SIZE

public static final int MAX_PACKET_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_TTL

public static final int MAX_TTL

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Constant Field Values

Constructor Detail

Packet

public Packet(int dest,
              int src,
              int ttl,
              int protocol,
              int seq,
              byte[] payload)
       throws java.lang.IllegalArgumentException

Constructing a new packet.

Parameters:

dest - The destination fishnet address.

src - The source fishnet address.

ttl - The time-to-live value for this packet.

protocol - What type of packet this is.

seq - The sequence number of the packet.

payload - The payload of the packet.

Throws:

java.lang.IllegalArgumentException - If the given arguments are invalid

Method Detail

toString

public java.lang.String toString()

Provides a string representation of the packet.

Overrides:

toString in class java.lang.Object

Returns:

A string representation of the packet.

getDest

public int getDest()

Returns:

The address of the destination node

getSrc

public int getSrc()

Returns:

The address of the src node

getTTL

public int getTTL()

Returns:

The TTL of the packet

setTTL

public void setTTL(int ttl)

Sets the TTL of this packet

Parameters:

ttl - TTL to set

getProtocol

public int getProtocol()

Returns:

The protocol used for this packet

getSeq

public int getSeq()

Returns:

The sequence number of this packet

getPayload

public byte[] getPayload()

Returns:

The payload of this packet

pack

public byte[] pack()

Convert the Packet object into a byte array for sending over the wire. Format: destination address: 1 byte source address: 1 byte ttl (time to live): 1 byte protocol: 1 byte packet length: 1 byte packet sequence num: 4 bytes payload: <= MAX_PAYLOAD_SIZE bytes

Returns:

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

unpack

public static Packet unpack(byte[] packedPacket)

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

Parameters:

packedPacket - String representation of the packet

Returns:

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

validAddress

public static boolean validAddress(int addr)

Tests if the address is a valid one

Parameters:

addr - Address to check

Returns:

True is address is valid, else false

isValid

public boolean isValid()

Tests if this Packet is valid or not

Returns:

True if packet is valid, else false