robot3
Class LNPManager

java.lang.Object
  |
  +--robot3.LNPManager

All Implemented Interfaces:

java.lang.Runnable

public final class LNPManager

extends java.lang.Object

implements java.lang.Runnable

This class handles the whole LNP protocol. As soon as you create a new instance of this class, i.e. the first time you call the getInstance method, a new thread is created that keeps the IR tower awake. The tower sends then a 0 every 4th second. Example of use :
LNPManager manager = LNPManager.getInstance("COM1");
manager.addLNPListener(this);
manager.integrityWrite("This is a test");
History:
01/13/2001: 1st release date
Problems known :
- the manager receives its own packets
- the manager can only handle one IR tower at a time
- there is no simple way to stop the manager from keeping the IR tower alive and from reading data from the IR tower, i.e. even when your main method is finished, the JVM doesn't stop.

Nested Class Summary

private class

LNPManager.WakeupThread This class keeps the tower awake by sending a 0 every 4th second.

Field Summary

private javax.comm.SerialPort	IRTower The serial port to which the IRTower is connected
private java.util.Vector	listeners The Vector containing the listeners
private byte	lnpHostAddress The hostAddress, which can be changed by calling setHostAddress, 0x10 by default.
private static byte	lnpHostMask The lnpHostMask, 0xF0 by default
private static byte	lnpPortMask The lnpPortMask, 0x0F by default
private static int	MAX_SIZE The maximum size of a LNP packet
private static LNPManager	theInstance Contains the only instance of the LNPManager.

Constructor Summary

private

LNPManager(java.lang.String comPort) Private constructor of the class.

Method Summary

void	addLNPListener(LNPListener listener) This methods adds the parameter to the list of the listener to call when a new message (integrity or addressing) is received.
private void	addressingRead(java.io.InputStream in) Called by run when a 0xF1 is received.
void	addressingWrite(byte[] data, byte sourcePort, byte destHostId, byte destPort) Sends a addressing packet containing the data of the parameter.
void	addressingWrite(java.lang.String data, byte sourcePort, byte destHostId, byte destPort) Sends a addressing packet containing the data of the parameter.
private static boolean	checkChecksum(byte firstByte, byte length, byte[] data, byte checksum) Checks if the checksum is correct.
private static int	checksum(byte[] data, int length) Computes the checksum.
static LNPManager	getInstance(java.lang.String comPort) Static mlethod that return an instance of the current class.
private void	integrityRead(java.io.InputStream in) Called by the read loop when a 0xF0 is read from the serial port.
void	integrityWrite(byte[] data) Sends a integrity packet containing the data of the parameter.
void	integrityWrite(java.lang.String data) Sends a integrity packet containing the data of the parameter.
private void	logicalWrite(byte[] data) Used to send a logical packet, i.e.
private void	openPort(java.lang.String comPort) Opens the serial port to which the IR tower is connected.
void	removeLNPListener(LNPListener listener) Removes the parameter from the list of the listeners to call when a new message is received.
void	run() DO NOT CALL THIS METHOD DIRECTLY : it's public because it is the implementation of a interface.
private void	sendAddressingEvent(byte[] buffer) Sends a WrongChecksumEvent to all the listeners.
private void	sendIntegrityEvent(byte[] buffer) Sends a IntegrityEvent to all the listeners.
private void	sendWrongChecksumEvent() Sends a WrongChecksumEvent to all the listeners.
void	setHostAddress(int hostAddress) Sets the host address of the LNPManager.

Methods inherited from class java.lang.Object

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

Field Detail

theInstance

private static LNPManager theInstance

Contains the only instance of the LNPManager.

lnpHostMask

private static final byte lnpHostMask

The lnpHostMask, 0xF0 by default

See Also:

Constant Field Values

lnpPortMask

private static final byte lnpPortMask

The lnpPortMask, 0x0F by default

See Also:

Constant Field Values

lnpHostAddress

private byte lnpHostAddress

The hostAddress, which can be changed by calling setHostAddress, 0x10 by default.

listeners

private java.util.Vector listeners

The Vector containing the listeners

IRTower

private javax.comm.SerialPort IRTower

The serial port to which the IRTower is connected

MAX_SIZE

private static final int MAX_SIZE

The maximum size of a LNP packet

See Also:

Constant Field Values

Constructor Detail

LNPManager

private LNPManager(java.lang.String comPort)

Private constructor of the class. The constructor is private because this class implements the singleton pattern (i.e., to get an instance, you call the static method getInstance(). The method stats a new thread that keeps the IR tower awake.

Parameters:

comPort - the name of the serial port to which the IR tower is connected.

Method Detail

getInstance

public static LNPManager getInstance(java.lang.String comPort)

Static mlethod that return an instance of the current class. If no other instance exists, creates one. The class cannot handle two IR towers at that time. If you ever try to do so, it will lead to some undefined behavior.

Parameters:

comPort - the name of the serial port to which the IR tower is connected.

Returns:

a new instance of the class if no other instance was created, or the last isntance used.

addLNPListener

public void addLNPListener(LNPListener listener)

This methods adds the parameter to the list of the listener to call when a new message (integrity or addressing) is received. At the current time, the LNPManager dispatches all the messages received, even if the listners don't have the corrct port number.

Parameters:

listener - the new object to call when a new message is received.

removeLNPListener

public void removeLNPListener(LNPListener listener)

Removes the parameter from the list of the listeners to call when a new message is received.

Parameters:

listener - the object to remove from the list of the listeners to call when a new message is received.

openPort

private void openPort(java.lang.String comPort)

Opens the serial port to which the IR tower is connected. This methods also sets some parameter to the serial port : baud rate : 2400, 8 databits, 1 stopbit, no parity.

Parameters:

comPort - the serial port to which the IR tower is connected.

run

public void run()

DO NOT CALL THIS METHOD DIRECTLY : it's public because it is the implementation of a interface. When a new LNPMAnager is created, the constructor creates a new thread, that calls this method. It starts a new wake up thread, and loops on what is received on the serial port.

Specified by:

run in interface java.lang.Runnable

integrityRead

private void integrityRead(java.io.InputStream in)

Called by the read loop when a 0xF0 is read from the serial port. Reads the packet, checks the checksum, and (if ok) sends a event to all the listeners. If the checksum is wrong, sends a wrong checksum event to the listeners.

Parameters:

in - the InputStream from which to read the data.

sendIntegrityEvent

private void sendIntegrityEvent(byte[] buffer)

Sends a IntegrityEvent to all the listeners.

Parameters:

buffer - the buffer

sendWrongChecksumEvent

private void sendWrongChecksumEvent()

Sends a WrongChecksumEvent to all the listeners.

sendAddressingEvent

private void sendAddressingEvent(byte[] buffer)

Sends a WrongChecksumEvent to all the listeners. Extracts from, to and data informations from the buffer, and call the appropriate method of the interface.

Parameters:

buffer - The buffer containing the received data.

addressingRead

private void addressingRead(java.io.InputStream in)

Called by run when a 0xF1 is received. Reads the length, the data, checks the checksum, sends an addressing event to the listeners if the checksum is Ok, a wrong checksum event otherwise.

Parameters:

in - the InputStream from which to read the data.

integrityWrite

public void integrityWrite(java.lang.String data)

Sends a integrity packet containing the data of the parameter.

Parameters:

data - the data to send.

integrityWrite

public void integrityWrite(byte[] data)

Sends a integrity packet containing the data of the parameter.

Parameters:

data - the data to send.

addressingWrite

public void addressingWrite(java.lang.String data,
                            byte sourcePort,
                            byte destHostId,
                            byte destPort)

Sends a addressing packet containing the data of the parameter.

Parameters:

data - the data to send.

sourcePort - the port number from which you send the data

destHostId - the host to which you send the data

addressingWrite

public void addressingWrite(byte[] data,
                            byte sourcePort,
                            byte destHostId,
                            byte destPort)

Sends a addressing packet containing the data of the parameter.

Parameters:

data - the data to send.

sourcePort - the port number from which you send the data

destHostId - the host to which you send the data

checksum

private static int checksum(byte[] data,
                            int length)

Computes the checksum.

Parameters:

data - the data on which to perform the checksum

length - the length on which to perform the checksum

Returns:

the checksum

checkChecksum

private static boolean checkChecksum(byte firstByte,
                                     byte length,
                                     byte[] data,
                                     byte checksum)

Checks if the checksum is correct.

Parameters:

firstByte - 0xF0 or 0XF1, depending on the kind of packet

length - the length on which to check the checksum

data - the data on which to check the checksum

checksum - the received checksum

Returns:

true if the checksum is ok, false otherwise.

logicalWrite

private void logicalWrite(byte[] data)

Used to send a logical packet, i.e. a raw packet. Waits for the IR tower to be available, and sends the data to it. param data the data to send.

setHostAddress

public void setHostAddress(int hostAddress)

Sets the host address of the LNPManager. This method automatically applies the hostMask to the parameter.

Parameters:

hostAddress - : the address of the LNPManager.