ch.dermitza.securenio.packet.worker

Class VariableLengthPacketWorker

java.lang.Object

ch.dermitza.securenio.packet.worker.AbstractPacketWorker

ch.dermitza.securenio.packet.worker.VariableLengthPacketWorker

All Implemented Interfaces:

java.lang.Runnable

Direct Known Subclasses:

TestPacketWorker

public abstract class VariableLengthPacketWorker
extends AbstractPacketWorker

An abstract, extensible implementation of a variable length packet worker. This worker extends AbstractPacketWorker to support variable length packets.

For the default implementation, packets should extend PacketIF and have a 3-byte header: 1 byte for packet designation and 2 bytes for message length. This results in 255 packet types, with maximum packet length of 32,767 bytes if using java shorts or 65,535 bytes if using an unsigned length implementation. NOTE: packet length excludes the 3-byte header, i.e. is payload length. If more packet types or a larger packet (payload) size is needed, use the argument constructor. Note that the largest header size the constructor can take is 2 bytes, and the length variable can either be 2 or 4 bytes, representing java shorts and ints respectively.

Application code should extend the singular method assemblePacket(ch.dermitza.securenio.socket.SocketIF, short, byte[]) to assemble the reconstructed packet and subsequently AbstractPacketWorker.fireListeners(SocketIF, ch.dermitza.securenio.packet.PacketIF) with the reconstructed packet.

Field Summary

Fields

Modifier and Type	Field and Description
static int	HEADER_LENGTH The default header length
static int	SIZE_LENGTH The default packet size length

Fields inherited from class ch.dermitza.securenio.packet.worker.AbstractPacketWorker

pendingData, pendingSockets

Constructor Summary

Constructors

Constructor and Description
VariableLengthPacketWorker() Initializes this packet worker to work with packets having a 1 byte header and 2 bytes payload length.
VariableLengthPacketWorker(boolean singleByte, boolean shortSize) Initializes this packet worker to work with packets having a custom header and payload length.

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract void	assemblePacket(SocketIF socket, short head, byte[] data) This method is called from the packet worker when a complete packet has been received.
protected void	processData() Process data received on pending sockets, in a FIFO fashion.

Methods inherited from class ch.dermitza.securenio.packet.worker.AbstractPacketWorker

addData, addListener, fireListeners, isRunning, removeListener, run, setRunning

Methods inherited from class java.lang.Object

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

Field Detail

HEADER_LENGTH

public static final int HEADER_LENGTH

The default header length

See Also:

Constant Field Values

SIZE_LENGTH

public static final int SIZE_LENGTH

The default packet size length

See Also:

Constant Field Values

Constructor Detail

VariableLengthPacketWorker

public VariableLengthPacketWorker(boolean singleByte,
                          boolean shortSize)

Initializes this packet worker to work with packets having a custom header and payload length.

Parameters:

singleByte - true if the header is one byte, false if it is 2 bytes long

shortSize - true if the payload length is 2 bytes, false if it is 4 bytes long

VariableLengthPacketWorker

public VariableLengthPacketWorker()

Initializes this packet worker to work with packets having a 1 byte header and 2 bytes payload length.

Method Detail

processData

protected void processData()

Process data received on pending sockets, in a FIFO fashion. If data received is not enough to reconstruct a packet, the socket's pending status is removed, as we cannot do further processing on it. The socket's pending status will be re-instantiated once more data on that particular socket has been received. Sockets that have been completely drained from data are also removed here.

Specified by:

processData in class AbstractPacketWorker

assemblePacket

protected abstract void assemblePacket(SocketIF socket,
                  short head,
                  byte[] data)

This method is called from the packet worker when a complete packet has been received. It should be extended to reconstruct the packet into what the application code needs, and subsequently fire the packet listeners to act on the packet received.

Parameters:

socket - The socket on which a complete packet was received

head - The head of the packet

data - The packet's payload

See Also:

AbstractPacketWorker.fireListeners(SocketIF, ch.dermitza.securenio.packet.PacketIF)