Package jmri.jmrix.zimo

Class Mx1Packetizer

java.lang.Object

jmri.jmrix.zimo.Mx1TrafficController

jmri.jmrix.zimo.Mx1Packetizer

All Implemented Interfaces:

Mx1Interface

public class Mx1Packetizer
extends Mx1TrafficController

Access to Zimo Mx1 messages via stream-based I/O. The "Mx1Interface" * side sends/receives Mx1Message objects. The connection to a Mx1PortController is via a pair of *Streams, which then carry sequences of characters for transmission.

Messages come to this via the main GUI thread, and are forwarded back to listeners in that same thread. Reception and transmission are handled in dedicated threads by RcvHandler and XmtHandler objects. Those are internal classes defined here. The thread priorities are:

• RcvHandler - at highest available priority
• XmtHandler - down one, which is assumed to be above the GUI
• (everything else)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	Mx1Packetizer.MessageQueued
(package private) class	Mx1Packetizer.RcvHandler	Handle incoming characters.
(package private) class	Mx1Packetizer.RetryHandler	Class to handle the re-transmission of messages that have not had a Level 1 response from the command station.
(package private) class	Mx1Packetizer.XmtHandler	Captive class to handle transmission

Field Summary

Fields

Modifier and Type	Field	Description
(package private) final int[]	crc8bit_table
(package private) static final int	DLE
(package private) static final int	EOT
(package private) DataInputStream	istream
(package private) byte	lastSequence
(package private) OutputStream	ostream
(package private) Mx1Packetizer.RcvHandler	rcvHandler	RcvHandler (a local class) object to implement the receive thread
(package private) Mx1Packetizer.RetryHandler	retryHandler	XmtHandler (a local class) object to implement the transmit thread
(package private) static final int	SOH
(package private) Mx1Packetizer.XmtHandler	xmtHandler	XmtHandler (a local class) object to implement the transmit thread
(package private) LinkedList<byte[]>	xmtList	Synchronized list used as a transmit queue
(package private) ConcurrentHashMap<Integer,Mx1Packetizer.MessageQueued>	xmtPackets

Fields inherited from class jmri.jmrix.zimo.Mx1TrafficController

adaptermemo, ASCII, BINARY, listeners, mCommandStation, protocol

Fields inherited from interface jmri.jmrix.zimo.Mx1Interface

ALL, POWER, PROGRAMMING, SENSORS, SLOTINFO, TURNOUTS

Constructor Summary

Constructors

Constructor	Description
Mx1Packetizer(Mx1CommandStation pCommandStation, boolean prot)

Method Summary

Modifier and Type	Method	Description
void	connectPort(Mx1PortController p)	Make connection to existing Mx1PortController object.
void	disconnectPort(Mx1PortController p)	Break connection to existing LnPortController object.
(package private) void	formatByteToPacket(byte b, ArrayList<Byte> message)
int	get16BitCRC(Mx1Message m)
(package private) byte	get8BitCRC(Mx1Message m)
(package private) byte	getNextSequenceNo()
(package private) void	isAckReplyRequired(Mx1Message m)
(package private) void	l1AckPacket(Mx1Message m)
(package private) void	l2AckPacket(Mx1Message m)
(package private) void	notifyLater(Mx1Message m, Mx1Listener reply)
(package private) void	processPacketForSending(Mx1Message m)
protected byte	readByteProtected(DataInputStream istream)	Read a single byte, protecting against various timeouts, etc.
void	sendMx1Message(Mx1Message m, Mx1Listener reply)	Forward a preformatted Mx1Message to the actual interface.
void	startThreads()	Invoked at startup to start the threads needed here.
boolean	status()

Methods inherited from class jmri.jmrix.zimo.Mx1TrafficController

addMx1Listener, getAdapterMemo, getCommandStation, getProtocol, getSystemPrefix, getUserName, notify, removeMx1Listener, setAdapterMemo

Methods inherited from class java.lang.Object

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

Field Details

xmtList

LinkedList<byte[]> xmtList

Synchronized list used as a transmit queue

xmtPackets

ConcurrentHashMap<Integer,Mx1Packetizer.MessageQueued> xmtPackets

xmtHandler

Mx1Packetizer.XmtHandler xmtHandler

XmtHandler (a local class) object to implement the transmit thread

retryHandler

Mx1Packetizer.RetryHandler retryHandler

XmtHandler (a local class) object to implement the transmit thread

rcvHandler

Mx1Packetizer.RcvHandler rcvHandler

RcvHandler (a local class) object to implement the receive thread

istream

DataInputStream istream

ostream

OutputStream ostream

lastSequence

byte lastSequence

SOH

static final int SOH

See Also:

• Constant Field Values

EOT

static final int EOT

See Also:

• Constant Field Values

DLE

static final int DLE

See Also:

• Constant Field Values

crc8bit_table

final int[] crc8bit_table

Constructor Details

Mx1Packetizer

public Mx1Packetizer(Mx1CommandStation pCommandStation,
 boolean prot)

Method Details

status

public boolean status()

Specified by:

status in interface Mx1Interface

Specified by:

status in class Mx1TrafficController

sendMx1Message

public void sendMx1Message(Mx1Message m,
 Mx1Listener reply)

Forward a preformatted Mx1Message to the actual interface. End of Message is added here, then the message is converted to a byte array and queued for transmission

Specified by:

sendMx1Message in interface Mx1Interface

Specified by:

sendMx1Message in class Mx1TrafficController

Parameters:

m - Message to send; will be updated with CRC

reply - the listener to notify of a response

getNextSequenceNo

byte getNextSequenceNo()

processPacketForSending

void processPacketForSending(Mx1Message m)

formatByteToPacket

void formatByteToPacket(byte b,
 ArrayList<Byte> message)

connectPort

public void connectPort(Mx1PortController p)

Make connection to existing Mx1PortController object.

Parameters:

p - Port controller for connected. Save this for a later disconnect call

disconnectPort

public void disconnectPort(Mx1PortController p)

Break connection to existing LnPortController object. Once broken, attempts to send via "message" member will fail.

Parameters:

p - previously connected port

readByteProtected

protected byte readByteProtected(DataInputStream istream)
                          throws IOException

Read a single byte, protecting against various timeouts, etc.

When a port is set to have a receive timeout (via the enableReceiveTimeout() method), some will return zero bytes or an EOFException at the end of the timeout. In that case, the read should be repeated to get the next real character.

Parameters:

istream - the input stream

Returns:

the first byte in the stream

Throws:

IOException - if unable to read istream

notifyLater

void notifyLater(Mx1Message m,
 Mx1Listener reply)

isAckReplyRequired

void isAckReplyRequired(Mx1Message m)

l1AckPacket

void l1AckPacket(Mx1Message m)

l2AckPacket

void l2AckPacket(Mx1Message m)

startThreads

public void startThreads()

Invoked at startup to start the threads needed here.

get16BitCRC

public int get16BitCRC(Mx1Message m)

get8BitCRC

byte get8BitCRC(Mx1Message m)