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Accessing the platform in Java Encoder pdf417 in Java Accessing the platform

Accessing the platform generate, create pdf-417 2d barcode none on java projects QR Code Safe Use reader to these sources for m PDF 417 for Java ore details about using the parallel port and for aspects of serial port I/O not covered here.. 23.4.1 Port classes There are two types of port c Java PDF-417 2d barcode lasses in javax.comm. The abstract class CommPort holds methods to control and perform I/O over a speci c port.

The class CommPortIdentifier gives information about the ports on the system and can create an instance of CommPort for a given port. 23.4.

1.1 CommPort This abstract class for port representation includes various methods such as getInputStream()and getOutputStream() to obtain streams to transmit and receive data over a port. The subclasses of CommPort, also abstract, include: r SerialPort this class works with RS-232 ports.

Methods in this class provide for. control, monitoring, transmis sion and reception. You can set parameters such as the baud rate, parity, numbers of stop bits and data bits and can choose ow control protocols. Individual control pins, such as DTR (Data Terminal Ready) and CTS (Clear to Send), can be set directly.

r ParallelPort this class works with the 8-bit IEEE-1284 parallel (or printer) port. Methods allow for setting the port mode such as the extended and enhanced modes. Also, the transmission can be suspended and restarted (useful for pausing and restarting a printout), and several status messages can be read such as paper out and printer busy.

. Concrete subclasses of Serial PDF417 for Java Port and ParallelPort are available in javax.comm for each particular platform. You do not create instances of these classes directly from their constructors but from factory methods in the CommPortIdentifier class.

23.4.1.

2 CommPortIdentifier An instance of this class, discussed further in the next section, provides information about a speci c port, such as the port s name and type, but it does not set ownership of the port or allow for any control or I/O over the port. Instead, you use the open() method of an instance of CommPortIdentifier for a speci c port to obtain an instance of a CommPort subclass for that port. As with the SerialPort and ParallelPort classes, you do not normally obtain instances of CommPortIdentifier directly from a constructor but with a factory method in CommPortIdentifier.

. 23.4.2 Finding ports The CommPortIdentifier class barcode pdf417 for Java acts as both a source of information about ports on a system and also as a descriptor of a particular port. The static method. 23.4 Port communications getPortIdentifers()provides a list of CommPortIdentifier objects for each port, serial and paralle l, on the platform:. Enumeration portList = CommPo Java PDF417 rtIdentifier.getPortIdentifiers ();. This enumeration lists the in stances of CommPortIdentifier, one for each port. The methods of this class provide information about the particular port such as its name and type via getName()and getPortType(), respectively, as the PortList example below illustrates:. import javax.comm.*; import j pdf417 2d barcode for Java ava.

util.*; /** List all the ports available on the local machine. **/ public class PortList.

public static void main (Stri ng[] args) { Enumeration port-list = CommPortIdentifier.getPortIdentifiers (); while (port-list.hasMoreElements ()) { CommPortIdentifier port-id = (CommPortIdentifier) port-list.

nextElement (); if (port-id.getPortType () == CommPortIdentifier.PORT-SERIAL) { System.

out.println ("Serial port: " + port-id.getName ());.

} else if (port-id.getPortTyp pdf417 2d barcode for Java e () == CommPortIdentifier.PORT-PARALLEL) { System.

out.println ("Parallel port: " + port-id.getName ()); } else System.

out.println ("Other port: " + port-id.getName ()); } } // main } // class PortList.

We used the constants PORT-SE RIAL and PORT-PARALLEL from the CommPortIdentifier class to test for the port type. On a desktop machine with four serial ports and two parallel ports, the output would go as:. Serial port: COM1 Serial port PDF-417 2d barcode for Java : COM2 Serial port: COM3 Serial port: COM4 Parallel port: LPT1 Parallel port: LPT2. Accessing the platform Conversely, you can test for jsp pdf417 2d barcode the presence of a port with a particular name, as follows:. import javax.comm.*; import j ava.

util.*; /** Look for COM# ports on the local machine. **/ public class PortTest.

public static void main (Stri barcode pdf417 for Java ng[] args) { String port-name; int i = 0; while (true) { i++; port-name = "COM" + i; try { CommPortIdentifier port-id = CommPortIdentifier.getPortIdentifier (port-name); System.out.

println ("Port " + port-name + " exists");. } catch (NoSuchPortException e) { System.out.println ("No port " + port-name); break; } } } // main } // class PortTest.

The output of this program mi servlet pdf417 2d barcode ght go as:.
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