java.lang.Object
- jmri.jmrix.mrc.MrcTrafficController
- - jmri.jmrix.mrc.MrcPacketizer

All Implemented Interfaces:

MrcInterface
```
public class MrcPacketizer
extends MrcTrafficController
```
Converts Stream-based I/O to/from Mrc messages. The "MrcInterface" side sends/receives MrcMessage objects. The connection to a MrcPortController is via a pair of *Streams, which then carry sequences of characters for transmission.
This is based upon the Packetizer used for LocoNet Connections due to its speed and efficiency to handle messages. This also takes some code from the AbstractMRTrafficController, when dealing with handling replies to messages sent. The MRC Command Station sends out a poll message to each handset which then has approximately 20ms to initially respond with a request. Otherwise the Command Station will poll the next handset.
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)
Some of the message formats used in this class are Copyright MRC, Inc. and used with permission as part of the JMRI project. That permission does not extend to uses in other software products. If you wish to use this code, algorithm or these message formats outside of JMRI, please contact Mrc Inc for separate permission.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`(package private) static class`	`MrcPacketizer.Echo`
`(package private) static class`	`MrcPacketizer.Failed`
`(package private) class`	`MrcPacketizer.RcvHandler`	Captive class to handle incoming characters.
`(package private) class`	`MrcPacketizer.XmtHandler`	Captive class to handle transmission

Field Summary

Fields
Modifier and Type	Field	Description
`(package private) static int`	`BADCOMMAND`
`(package private) static int`	`CONFIRMATIONONLY`
`(package private) int`	`consecutiveMissedPolls`
`MrcPortController`	`controller`
`(package private) static int`	`DOUBLELOCOCONTROL`
`protected boolean`	`echo`	true if the external hardware is not echoing messages, so we must
`(package private) static int`	`IDLESTATE`
`java.io.DataInputStream`	`istream`
`(package private) int`	`mCurrentState`
`(package private) static int`	`MISSEDPOLL`
`(package private) MrcMessage`	`noData`
`(package private) byte[]`	`noDataMsg`
`java.io.OutputStream`	`ostream`
`protected java.lang.Runnable`	`rcvHandler`	RcvHandler (a local class) object to implement the receive thread
`(package private) static java.lang.Object`	`transmitLock`
`(package private) static int`	`WAITFORCMDRECEIVED`
`protected java.lang.Runnable`	`xmtHandler`	XmtHandler (a local class) object to implement the transmit thread
`java.util.LinkedList<MrcMessage>`	`xmtList`	Synchronized list used as a transmit queue.

Fields inherited from class jmri.jmrix.mrc.MrcTrafficController
adaptermemo, cabAddress, receivedByteCount, receivedMsgCount, trafficListeners, transmittedMsgCount

Fields inherited from interface jmri.jmrix.mrc.MrcInterface
ALL, CLOCK, POLL, POWER, PROGRAMMING, SENSORS, THROTTLEINFO, TURNOUTS

Constructor Summary

Constructors
Constructor Description

MrcPacketizer()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`connectPort(MrcPortController p)`	Make connection to existing MrcPortController object.
`void`	`disconnectPort(MrcPortController p)`	Break connection to existing MrcPortController object.
`boolean`	`isXmtBusy()`	Implement abstract method to signal if there's a backlog of information waiting to be sent.
`protected void`	`messageFailed(MrcMessage m)`
`protected void`	`messageTransmitted(MrcMessage msg)`	When a message is finally transmitted, forward it to listeners if echoing is needed.
`protected byte`	`readByteProtected(java.io.DataInputStream istream)`	Read a single byte, protecting against various timeouts, etc.
`void`	`sendMrcMessage(MrcMessage m)`	Forward a preformatted MrcMessage to the actual interface.
`void`	`startThreads()`	Invoked at startup to start the threads needed here.
`boolean`	`status()`
`protected void`	`transmitWait(int waitTime, int state, java.lang.String InterruptMessage, int x)`

Methods inherited from class jmri.jmrix.mrc.MrcTrafficController
addTrafficListener, changeTrafficListener, getAdapterMemo, getCabNumber, getReceivedByteCount, getReceivedMsgCount, getSystemPrefix, getTransmittedMsgCount, getUserName, notifyRcv, notifyXmit, removeTrafficListener, resetStatistics, setAdapterMemo, setCabNumber

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - echo
```
protected boolean echo
```
    true if the external hardware is not echoing messages, so we must
  - xmtList
```
public java.util.LinkedList<MrcMessage> xmtList
```
    Synchronized list used as a transmit queue.
    This is public to allow access from the internal class(es) when compiling with Java 1.1
  - xmtHandler
```
protected java.lang.Runnable xmtHandler
```
    XmtHandler (a local class) object to implement the transmit thread
  - rcvHandler
```
protected java.lang.Runnable rcvHandler
```
    RcvHandler (a local class) object to implement the receive thread
  - controller
```
public MrcPortController controller
```
  - istream
```
public java.io.DataInputStream istream
```
  - ostream
```
public java.io.OutputStream ostream
```
  - IDLESTATE
```
static final int IDLESTATE
```
    See Also:
    
    Constant Field Values
  - WAITFORCMDRECEIVED
```
static final int WAITFORCMDRECEIVED
```
    See Also:
    
    Constant Field Values
  - DOUBLELOCOCONTROL
```
static final int DOUBLELOCOCONTROL
```
    See Also:
    
    Constant Field Values
  - MISSEDPOLL
```
static final int MISSEDPOLL
```
    See Also:
    
    Constant Field Values
  - BADCOMMAND
```
static final int BADCOMMAND
```
    See Also:
    
    Constant Field Values
  - CONFIRMATIONONLY
```
static final int CONFIRMATIONONLY
```
    See Also:
    
    Constant Field Values
  - mCurrentState
```
int mCurrentState
```
  - consecutiveMissedPolls
```
int consecutiveMissedPolls
```
  - noData
```
final MrcMessage noData
```
  - noDataMsg
```
final byte[] noDataMsg
```
  - transmitLock
```
static final java.lang.Object transmitLock
```
- Constructor Detail
  - MrcPacketizer
```
public MrcPacketizer()
```
- Method Detail
  - status
```
public boolean status()
```
    Specified by:
    
    status in interface MrcInterface
    
    Specified by:
    
    status in class MrcTrafficController
  - sendMrcMessage
```
public void sendMrcMessage(MrcMessage m)
```
    Forward a preformatted MrcMessage to the actual interface. The message is converted to a byte array and queue for transmission
    
    Specified by:
    
    sendMrcMessage in interface MrcInterface
    
    Specified by:
    
    sendMrcMessage in class MrcTrafficController
    
    Parameters:
    
    m - Message to send;
  - isXmtBusy
```
public boolean isXmtBusy()
```
    Implement abstract method to signal if there's a backlog of information waiting to be sent.
    
    Specified by:
    
    isXmtBusy in class MrcTrafficController
    
    Returns:
    
    true if busy, false if nothing waiting to send
  - connectPort
```
public void connectPort(MrcPortController p)
```
    Make connection to existing MrcPortController object.
    
    Parameters:
    
    p - Port controller for connected. Save this for a later disconnect call
  - disconnectPort
```
public void disconnectPort(MrcPortController p)
```
    Break connection to existing MrcPortController object. Once broken, attempts to send via "message" member will fail.
    
    Parameters:
    
    p - previously connected port
  - readByteProtected
```
protected byte readByteProtected(java.io.DataInputStream istream)
                          throws java.io.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 - data input stream from layout
    
    Returns:
    
    byte stream from interface
    
    Throws:
    
    java.io.IOException - from read errors
  - transmitWait
```
protected void transmitWait(int waitTime,
                            int state,
                            java.lang.String InterruptMessage,
                            int x)
```
  - messageFailed
```
protected void messageFailed(MrcMessage m)
```
  - messageTransmitted
```
protected void messageTransmitted(MrcMessage msg)
```
    When a message is finally transmitted, forward it to listeners if echoing is needed.
    
    Parameters:
    
    msg - message to tag a transmitted message
  - startThreads
```
public void startThreads()
```
    Invoked at startup to start the threads needed here.

Class MrcPacketizer

Nested Class Summary

Field Summary

Fields inherited from class jmri.jmrix.mrc.MrcTrafficController

Fields inherited from interface jmri.jmrix.mrc.MrcInterface

Constructor Summary

Method Summary

Methods inherited from class jmri.jmrix.mrc.MrcTrafficController

Methods inherited from class java.lang.Object

Field Detail

echo

xmtList

xmtHandler

rcvHandler

controller

istream

ostream

IDLESTATE

WAITFORCMDRECEIVED

DOUBLELOCOCONTROL

MISSEDPOLL

BADCOMMAND

CONFIRMATIONONLY

mCurrentState

consecutiveMissedPolls

noData

noDataMsg

transmitLock

Constructor Detail

MrcPacketizer

Method Detail

status

sendMrcMessage

isXmtBusy

connectPort

disconnectPort

readByteProtected

transmitWait

messageFailed

messageTransmitted

startThreads