Class Layer2Frame

java.lang.Object

Layer2Frame

public class Layer2Frame
extends java.lang.Object

This class represents a Layer2 Frame according to our protocol definition. It can be used to create a new Layer2Frame from values, or to parse a string of bits into a Layer2Frame instance.

Field Summary

Fields

Modifier and Type	Field and Description
static int	BCAST_ADDRESS

Constructor Summary

Constructors

Constructor and Description
Layer2Frame(int destAddr, int srcAddr, int vlanId, java.lang.String payload) Create a new Layer2Frame, given values for many fields, and deriving the values for the other fields.
Layer2Frame(java.lang.String bits) Given a string of bits which should be a legal Layer2Frame, parse it into its component pieces.

Method Summary

Modifier and Type	Method and Description
static java.lang.String	computeParity(java.lang.String bits, int len) Compute the parity of the string of bits, by counting the number of 1 bits in the string and return the result as a 0-padded bit String of the given length.
int	getDestAddr()
int	getLength()
int	getParity()
java.lang.String	getPayload()
int	getSrcAddr()
int	getVlanId()
static java.lang.String	toBinary(int val, int length) Convert the integer value val to a string of 0s and 1s of the given length.
static int	toDecimal(java.lang.String bits)
java.lang.String	toString() Create the String of 0s and 1s representing the whole frame, with the parity field on the end, and the 0 pre-amble field on the front.

Methods inherited from class java.lang.Object

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

Field Detail

BCAST_ADDRESS

public static int BCAST_ADDRESS

Constructor Detail

Layer2Frame

public Layer2Frame(int destAddr,
                   int srcAddr,
                   int vlanId,
                   java.lang.String payload)

Create a new Layer2Frame, given values for many fields, and deriving the values for the other fields. This method is used when the code is creating a new frame to be sent. The other constructor is used for parsing a received Layer2Frame as a string of bits.

Layer2Frame

public Layer2Frame(java.lang.String bits)

Given a string of bits which should be a legal Layer2Frame, parse it into its component pieces. Throw an error if there are problems.

Method Detail

getDestAddr

public int getDestAddr()

getSrcAddr

public int getSrcAddr()

getLength

public int getLength()

getVlanId

public int getVlanId()

getPayload

public java.lang.String getPayload()

getParity

public int getParity()

toBinary

public static java.lang.String toBinary(int val,
                                        int length)

Convert the integer value val to a string of 0s and 1s of the given length.

computeParity

public static java.lang.String computeParity(java.lang.String bits,
                                             int len)

Compute the parity of the string of bits, by counting the number of 1 bits in the string and return the result as a 0-padded bit String of the given length. The code mods the value to fit in the given length.

toDecimal

public static int toDecimal(java.lang.String bits)

toString

public java.lang.String toString()

Create the String of 0s and 1s representing the whole frame, with the parity field on the end, and the 0 pre-amble field on the front.

Overrides:

toString in class java.lang.Object