lejos.nxt.rcxcomm
Class PacketHandler

java.lang.Object
  lejos.nxt.rcxcomm.PacketHandler

Direct Known Subclasses:

LLCHandler, LLCReliableHandler

public abstract class PacketHandler
extends Object

Abstract packet handler. Implementations must include sendPacket, receivePacket and isPacketAvailable(). The other methods are optional.

Field Summary

protected PacketHandler

lowerHandler

Constructor Summary

PacketHandler()

PacketHandler(PacketHandler handler)

Method Summary

void	close() Close this packet handler and all lower layers.
int	getError() Get the last error.
boolean	isAckAvailable() Check if an ack is available
abstract boolean	isPacketAvailable() Check if a packet is available
void	open(byte source, byte destination) Set the source and destination for this connection.
int	receiveAck(byte[] buffer)
abstract int	receivePacket(byte[] buffer) Receive a packet.
void	reset() Reset sequence numbers for this handler
abstract boolean	sendPacket(byte[] packet, int len) Send a packet.
void	setListen(boolean listen) Set or unset the listen flag to keep a PC serial tower alive

Methods inherited from class java.lang.Object

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

Field Detail

lowerHandler

protected PacketHandler lowerHandler

Constructor Detail

PacketHandler

public PacketHandler()

PacketHandler

public PacketHandler(PacketHandler handler)

Method Detail

open

public void open(byte source,
                 byte destination)

Set the source and destination for this connection.

reset

public void reset()

Reset sequence numbers for this handler

setListen

public void setListen(boolean listen)

Set or unset the listen flag to keep a PC serial tower alive

Parameters:

listen - true to set listen mode, else false

sendPacket

public abstract boolean sendPacket(byte[] packet,
                                   int len)

Send a packet.

Parameters:

packet - the bytes to send

len - the number of bytes to send

Returns:

true if the send was successful, else false

receivePacket

public abstract int receivePacket(byte[] buffer)

Receive a packet.

Parameters:

buffer - the buffer to receive the packet into

Returns:

the number of bytes received

receiveAck

public int receiveAck(byte[] buffer)

isPacketAvailable

public abstract boolean isPacketAvailable()

Check if a packet is available

Returns:

true if a Packet is available, else false

isAckAvailable

public boolean isAckAvailable()

Check if an ack is available

Returns:

true if a ack is available, else false

close

public void close()

Close this packet handler and all lower layers.

getError

public int getError()

Get the last error.

Returns:

the error number, or zero for success