lejos.pc.comm
Class NXTCommUSB

java.lang.Object
  lejos.pc.comm.NXTCommUSB

All Implemented Interfaces:

NXTCommRequest, NXTComm

Direct Known Subclasses:

NXTCommFantom, NXTCommLibnxt

public abstract class NXTCommUSB
extends java.lang.Object
implements NXTComm

Base Implementation of NXTComm for USB This module implements two types of I/O over USB. 1. The standard Lego LCP format used for LCP command processing. 2. A Simple packet based protocol that can be used to transport a simple byte stream. Protocol 2 is required (rather then using raw USB operations), to allow the signaling of things like open, and close over the connection. Notes This module assumes that the device read and write functions have a built in timeout period of approx 20 seconds. This module assumes that this timeout exists and uses it to timeout some requests. Should not be used directly - use NXTCommFactory to create an appropriate NXTComm object for your system and the protocol you are using.

Field Summary

Fields inherited from interface lejos.pc.comm.NXTComm

LCP, PACKET, RAW

Constructor Summary

NXTCommUSB()

Method Summary

int	available() The number of bytes that can be read without blocking.
void	close() Close the current device.
java.io.InputStream	getInputStream() Return an InputStream for reading a stream of data from the NXT over this connection.
java.io.OutputStream	getOutputStream() Return an OutputStream for writing a stream of data to the NXT over this connection.
boolean	open(NXTInfo nxt) Connect to a NXT found by a search or created from mname and address.
boolean	open(NXTInfo nxtInfo, int mode) Open a connection to the specified device, and make it available for use.
byte[]	read() Read bytes from the device
NXTInfo[]	search(java.lang.String name, int protocol) Locate availabe nxt devices and return them.
byte[]	sendRequest(byte[] data, int replyLen) Send a Lego Command Protocol (LCP) request to the device.
void	write(byte[] data) Write bytes to the device.

Methods inherited from class java.lang.Object

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

Constructor Detail

NXTCommUSB

public NXTCommUSB()

Method Detail

search

public NXTInfo[] search(java.lang.String name,
                        int protocol)

Locate availabe nxt devices and return them. Optionally filter the list to those that match name.

Specified by:

search in interface NXTComm

Parameters:

name - The name to search for. If null return all devices.

protocol - The protocol to search for, must be USB

Returns:

The list of devices.

open

public boolean open(NXTInfo nxtInfo,
                    int mode)

Open a connection to the specified device, and make it available for use.

Specified by:

open in interface NXTComm

Parameters:

nxtInfo - The device to connect to.

mode - the I/O mode to be used on this connection.

Returns:

true if the device is now open, false otherwise.

open

public boolean open(NXTInfo nxt)
             throws NXTCommException

Description copied from interface: NXTComm

Connect to a NXT found by a search or created from mname and address.

Specified by:

open in interface NXTComm

Parameters:

nxt - the NXTInfo object for the NXT

Returns:

true if the open succeeded

Throws:

NXTCommException

close

public void close()

Close the current device.

Specified by:

close in interface NXTCommRequest

sendRequest

public byte[] sendRequest(byte[] data,
                          int replyLen)
                   throws java.io.IOException

Send a Lego Command Protocol (LCP) request to the device.

Specified by:

sendRequest in interface NXTCommRequest

Parameters:

data - The command to send.

replyLen - How many bytes in the optional reply.

Returns:

The optional reply, or null

Throws:

java.io.IOException - Thrown on errors.

read

public byte[] read()
            throws java.io.IOException

Read bytes from the device

Specified by:

read in interface NXTComm

Returns:

An array of bytes read from the device. null if at EOF

Throws:

java.io.IOException

available

public int available()
              throws java.io.IOException

The number of bytes that can be read without blocking.

Specified by:

available in interface NXTComm

Returns:

Bytes available to be read.

Throws:

java.io.IOException

write

public void write(byte[] data)
           throws java.io.IOException

Write bytes to the device.

Specified by:

write in interface NXTComm

Parameters:

data - Data to be written.

Throws:

java.io.IOException

getOutputStream

public java.io.OutputStream getOutputStream()

Description copied from interface: NXTComm

Return an OutputStream for writing a stream of data to the NXT over this connection.

Specified by:

getOutputStream in interface NXTComm

Returns:

the OutputStream object

getInputStream

public java.io.InputStream getInputStream()

Description copied from interface: NXTComm

Return an InputStream for reading a stream of data from the NXT over this connection.

Specified by:

getInputStream in interface NXTComm

Returns:

the InputStream object