Java Reference
In-Depth Information
To summarize, the basic steps in using a communications port are as follows:
1. Get an Enumeration (see Using Iterators or Enumerations for Data-Independent Ac-
cess ) of CommPortIdentifier s by calling the static CommPortIdentifier method
getPortIdentifiers() , and choose the port you want.
2. Call the CommPortIdentifier 's open() method; cast the resulting CommPort object
to a SerialPort object or ParallelPort as appropriate.
3. Set the communications parameters (i.e., baud rate, parity, stop bits, and the like),
either individually or all at once, using the convenience routine setSeri-
alPortParams() for a serial port or “mode” for a parallel port.
4. Call the getInputStream and getOutputStream methods of the CommPort object,
and construct any additional Stream or Writer objects (see Chapter 10 ).
You are then ready to read and write on the port. Example 10-13 is code that implements all
these steps for a serial port. For parallel ports the API is similar; consult the online docu-
mentation.
Example 10-13. src/main/java/javacomm/CommPortSimple.java
/**
* Open a serial port using Java Communications.
* @author Ian F. Darwin, http://www.darwinsys.com/
*/
public
public class
class CommPortSimple
CommPortSimple {
private
private static
final String HELLO = "Hello?" ;
/** How long to wait for the open to finish up. */
public
static final
public static
int TIMEOUTSECONDS = 30 ;
/** The baud rate to use. */
public
static final
final int
public static
int BAUD = 19200 ;
/** The input stream */
protected
static final
final int
protected BufferedReader is ;
/** The output stream */
protected
protected PrintStream os ;
/** The chosen Port Identifier */
CommPortIdentifier thePortID ;
/** The chosen Port itself */
CommPort thePort ;
public
public static
static void
void main ( String [] argv ) throws
throws Exception {
iif ( argv . length != 1 ) {
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