Java/Development Class/COM Port

Choose a port, any port!

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.util.Enumeration; import java.util.HashMap; import javax.rum.rumPortIdentifier; import javax.rum.SerialPort; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; /**

* Choose a port, any port!
* 
* Java Communications is a "standard extention" and must be downloaded and
* installed separately from the JDK before you can even compile this program.
* 
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: PortChooser.java,v 1.9 2004/04/11 23:50:40 ian Exp $
*/

public class PortChooser extends JDialog implements ItemListener {

 /** A mapping from names to CommPortIdentifiers. */
 protected HashMap map = new HashMap();
 /** The name of the choice the user made. */
 protected String selectedPortName;
 /** The CommPortIdentifier the user chose. */
 protected CommPortIdentifier selectedPortIdentifier;
 /** The JComboBox for serial ports */
 protected JComboBox serialPortsChoice;
 /** The JComboBox for parallel ports */
 protected JComboBox parallelPortsChoice;
 /** The JComboBox for anything else */
 protected JComboBox other;
 /** The SerialPort object */
 protected SerialPort ttya;
 /** To display the chosen */
 protected JLabel choice;
 /** Padding in the GUI */
 protected final int PAD = 5;
 /**
  * This will be called from either of the JComboBoxen when the user selects
  * any given item.
  */
 public void itemStateChanged(ItemEvent e) {
   // Get the name
   selectedPortName = (String) ((JComboBox) e.getSource())
       .getSelectedItem();
   // Get the given CommPortIdentifier
   selectedPortIdentifier = (CommPortIdentifier) map.get(selectedPortName);
   // Display the name.
   choice.setText(selectedPortName);
 }
 /* The public "getter" to retrieve the chosen port by name. */
 public String getSelectedName() {
   return selectedPortName;
 }
 /* The public "getter" to retrieve the selection by CommPortIdentifier. */
 public CommPortIdentifier getSelectedIdentifier() {
   return selectedPortIdentifier;
 }
 /** A test program to show up this chooser. */
 public static void main(String[] ap) {
   PortChooser c = new PortChooser(null);
   c.setVisible(true); // blocking wait
   System.out.println("You chose " + c.getSelectedName() + " (known by "
       + c.getSelectedIdentifier() + ").");
   System.exit(0);
 }
 /**
  * Construct a PortChooser --make the GUI and populate the ComboBoxes.
  */
 public PortChooser(JFrame parent) {
   super(parent, "Port Chooser", true);
   makeGUI();
   populate();
   finishGUI();
 }
 /**
  * Build the GUI. You can ignore this for now if you have not yet worked
  * through the GUI chapter. Your mileage may vary.
  */
 protected void makeGUI() {
   Container cp = getContentPane();
   JPanel centerPanel = new JPanel();
   cp.add(BorderLayout.CENTER, centerPanel);
   centerPanel.setLayout(new GridLayout(0, 2, PAD, PAD));
   centerPanel.add(new JLabel("Serial Ports", JLabel.RIGHT));
   serialPortsChoice = new JComboBox();
   centerPanel.add(serialPortsChoice);
   serialPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Parallel Ports", JLabel.RIGHT));
   parallelPortsChoice = new JComboBox();
   centerPanel.add(parallelPortsChoice);
   parallelPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Unknown Ports", JLabel.RIGHT));
   other = new JComboBox();
   centerPanel.add(other);
   other.setEnabled(false);
   centerPanel.add(new JLabel("Your choice:", JLabel.RIGHT));
   centerPanel.add(choice = new JLabel());
   JButton okButton;
   cp.add(BorderLayout.SOUTH, okButton = new JButton("OK"));
   okButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       PortChooser.this.dispose();
     }
   });
 }
 /**
  * Populate the ComboBoxes by asking the Java Communications API what ports
  * it has. Since the initial information comes from a Properties file, it
  * may not exactly reflect your hardware.
  */
 protected void populate() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, putting serial and parallel into ComboBoxes
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier) pList.nextElement();
     // System.out.println("Port " + cpi.getName());
     map.put(cpi.getName(), cpi);
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       serialPortsChoice.setEnabled(true);
       serialPortsChoice.addItem(cpi.getName());
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       parallelPortsChoice.setEnabled(true);
       parallelPortsChoice.addItem(cpi.getName());
     } else {
       other.setEnabled(true);
       other.addItem(cpi.getName());
     }
   }
   serialPortsChoice.setSelectedIndex(-1);
   parallelPortsChoice.setSelectedIndex(-1);
 }
 protected void finishGUI() {
   serialPortsChoice.addItemListener(this);
   parallelPortsChoice.addItemListener(this);
   other.addItemListener(this);
   pack();
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

}

 </source>
   
  
 
  

Demonstrate the port conflict resolution mechanism

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.util.Enumeration; import java.util.HashMap; import javax.rum.rumPort; import javax.rum.rumPortIdentifier; import javax.rum.rumPortOwnershipListener; import javax.rum.NoSuchPortException; import javax.rum.ParallelPort; import javax.rum.PortInUseException; import javax.rum.SerialPort; import javax.rum.UnsupportedCommOperationException; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; /** Demonstrate the port conflict resolution mechanism.

* Run two copies of this program and choose the same port in each.
* $Id: PortOwner.java,v 1.1 2000/02/27 03:45:34 ian Exp $
*/

public class PortOwner extends CommPortOpen {

 /** A name for showing which of several instances of this program */
 String myName;
 public PortOwner(String name)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   super(null);
   myName = name;
   thePortID.addPortOwnershipListener(new MyResolver());
 }
 public void converse() {
   // lah de dah...
   // To simulate a long conversation on the port...
   
   try {
     Thread.sleep(1000 * 1000);
   } catch (InterruptedException cantHappen) {
     //
   }
 }
 /** An inner class that handles the ports conflict resolution. */
 class MyResolver implements CommPortOwnershipListener {
   protected boolean owned = false;
   public void ownershipChange(int whaHoppen) {
     switch (whaHoppen) {
     case PORT_OWNED:
       System.out.println("An open succeeded.");
       owned = true;
       break;
     case PORT_UNOWNED:
       System.out.println("A close succeeded.");
       owned = false;
       break;
     case PORT_OWNERSHIP_REQUESTED: 
       if (owned) {
         if (JOptionPane.showConfirmDialog(null,
           "I"ve been asked to give up the port, should I?",
           "Port Conflict (" + myName + ")",
           JOptionPane.OK_CANCEL_OPTION) == 0)
         thePort.close();
       } else {
         System.out.println("Somebody else has the port");
       }
     }
   }
 }
 public static void main(String[] argv)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   if (argv.length != 1) {
     System.err.println("Usage: PortOwner aname");
     System.exit(1);
   }
     
   new PortOwner(argv[0]).converse();
   System.exit(0);
 }

} /**

* Open a serial port using Java Communications.
*
* @author  Ian F. Darwin, http://www.darwinsys.ru/
*/

class CommPortOpen {

 /** How long to wait for the open to finish up. */
 public static final int TIMEOUTSECONDS = 30;
 /** The baud rate to use. */
 public static final int BAUD = 19200;
 /** The parent JFrame, for the chooser. */
 protected JFrame parent;
 /** The input stream */
 protected BufferedReader is;
 /** The output stream */
 protected PrintStream os;
 /** The chosen Port Identifier */
 CommPortIdentifier thePortID;
 /** The chosen Port itself */
 CommPort thePort;
 public static void main(String[] argv)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new CommPortOpen(null).converse();
   System.exit(0);
 }
 /* Constructor */
 public CommPortOpen(JFrame f)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   
   // Use the PortChooser from before. Pop up the JDialog.
   PortChooser chooser = new PortChooser(null);
   String portName = null;
   do {
     chooser.setVisible(true);
     
     // Dialog done. Get the port name.
     portName = chooser.getSelectedName();
     if (portName == null)
       System.out.println("No port selected. Try again.\n");
   } while (portName == null);
   // Get the CommPortIdentifier.
   thePortID = chooser.getSelectedIdentifier();
   // Now actually open the port.
   // This form of openPort takes an Application Name and a timeout.
   // 
   System.out.println("Trying to open " + thePortID.getName() + "...");
   switch (thePortID.getPortType()) {
   case CommPortIdentifier.PORT_SERIAL:
     thePort = thePortID.open("DarwinSys DataComm",
       TIMEOUTSECONDS * 1000);
     SerialPort myPort = (SerialPort) thePort;
     // set up the serial port
     myPort.setSerialPortParams(BAUD, SerialPort.DATABITS_8,
       SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
     break;
   case CommPortIdentifier.PORT_PARALLEL:
     thePort = thePortID.open("DarwinSys Printing",
       TIMEOUTSECONDS * 1000);
     ParallelPort pPort = (ParallelPort)thePort;
     // Tell API to pick "best available mode" - can fail!
     // myPort.setMode(ParallelPort.LPT_MODE_ANY);
     // Print what the mode is
     int mode = pPort.getMode();
     switch (mode) {
       case ParallelPort.LPT_MODE_ECP:
         System.out.println("Mode is: ECP");
         break;
       case ParallelPort.LPT_MODE_EPP:
         System.out.println("Mode is: EPP");
         break;
       case ParallelPort.LPT_MODE_NIBBLE:
         System.out.println("Mode is: Nibble Mode.");
         break;
       case ParallelPort.LPT_MODE_PS2:
         System.out.println("Mode is: Byte mode.");
         break;
       case ParallelPort.LPT_MODE_SPP:
         System.out.println("Mode is: Compatibility mode.");
         break;
       // ParallelPort.LPT_MODE_ANY is a "set only" mode;
       // tells the API to pick "best mode"; will report the
       // actual mode it selected.
       default:
         throw new IllegalStateException("Parallel mode " + 
           mode + " invalid.");
     }
     break;
   default:  // Neither parallel nor serial??
     throw new IllegalStateException("Unknown port type " + thePortID);
   }
   // Get the input and output streams
   // Printers can be write-only
   try {
     is = new BufferedReader(new InputStreamReader(thePort.getInputStream()));
   } catch (IOException e) {
     System.err.println("Can"t open input stream: write-only");
     is = null;
   }
   os = new PrintStream(thePort.getOutputStream(), true);
 }
 /** This method will be overridden by non-trivial subclasses
  * to hold a conversation. 
  */
 protected void converse() throws IOException {
   System.out.println("Ready to read and write port.");
   // Input/Output code not written -- must subclass.
   // Finally, clean up.
   if (is != null)
     is.close();
   os.close();
 }

} class PortChooser extends JDialog implements ItemListener {

 /** A mapping from names to CommPortIdentifiers. */
 protected HashMap map = new HashMap();
 /** The name of the choice the user made. */
 protected String selectedPortName;
 /** The CommPortIdentifier the user chose. */
 protected CommPortIdentifier selectedPortIdentifier;
 /** The JComboBox for serial ports */
 protected JComboBox serialPortsChoice;
 /** The JComboBox for parallel ports */
 protected JComboBox parallelPortsChoice;
 /** The JComboBox for anything else */
 protected JComboBox other;
 /** The SerialPort object */
 protected SerialPort ttya;
 /** To display the chosen */
 protected JLabel choice;
 /** Padding in the GUI */
 protected final int PAD = 5;
 /** This will be called from either of the JComboBoxen when the
  * user selects any given item.
  */
 public void itemStateChanged(ItemEvent e) {
   // Get the name
   selectedPortName = (String)((JComboBox)e.getSource()).getSelectedItem();
   // Get the given CommPortIdentifier
   selectedPortIdentifier = (CommPortIdentifier)map.get(selectedPortName);
   // Display the name.
   choice.setText(selectedPortName);
 }
 /* The public "getter" to retrieve the chosen port by name. */
 public String getSelectedName() {
   return selectedPortName;
 }
 /* The public "getter" to retrieve the selection by CommPortIdentifier. */
 public CommPortIdentifier getSelectedIdentifier() {
   return selectedPortIdentifier;
 }
 /** A test program to show up this chooser. */
 public static void main(String[] ap) {
   PortChooser c = new PortChooser(null);
   c.setVisible(true);  // blocking wait
   System.out.println("You chose " + c.getSelectedName() +
     " (known by " + c.getSelectedIdentifier() + ").");
   System.exit(0);
 }
 /** Construct a PortChooser --make the GUI and populate the ComboBoxes.
  */
 public PortChooser(JFrame parent) {
   super(parent, "Port Chooser", true);
   makeGUI();
   populate();
   finishGUI();
 }
 /** Build the GUI. You can ignore this for now if you have not
  * yet worked through the GUI chapter. Your mileage may vary.
  */
 protected void makeGUI() {
   Container cp = getContentPane();
   JPanel centerPanel = new JPanel();
   cp.add(BorderLayout.CENTER, centerPanel);
   centerPanel.setLayout(new GridLayout(0,2, PAD, PAD));
   centerPanel.add(new JLabel("Serial Ports", JLabel.RIGHT));
   serialPortsChoice = new JComboBox();
   centerPanel.add(serialPortsChoice);
   serialPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Parallel Ports", JLabel.RIGHT));
   parallelPortsChoice = new JComboBox();
   centerPanel.add(parallelPortsChoice);
   parallelPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Unknown Ports", JLabel.RIGHT));
   other = new JComboBox();
   centerPanel.add(other);
   other.setEnabled(false);
   centerPanel.add(new JLabel("Your choice:", JLabel.RIGHT));
   centerPanel.add(choice = new JLabel());
   JButton okButton;
   cp.add(BorderLayout.SOUTH, okButton = new JButton("OK"));
   okButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       PortChooser.this.dispose();
     }
   });
 }
 /** Populate the ComboBoxes by asking the Java Communications API
  * what ports it has.  Since the initial information comes from
  * a Properties file, it may not exactly reflect your hardware.
  */
 protected void populate() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, putting serial and parallel into ComboBoxes
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier)pList.nextElement();
     // System.out.println("Port " + cpi.getName());
     map.put(cpi.getName(), cpi);
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       serialPortsChoice.setEnabled(true);
       serialPortsChoice.addItem(cpi.getName());
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       parallelPortsChoice.setEnabled(true);
       parallelPortsChoice.addItem(cpi.getName());
     } else {
       other.setEnabled(true);
       other.addItem(cpi.getName());
     }
   }
   serialPortsChoice.setSelectedIndex(-1);
   parallelPortsChoice.setSelectedIndex(-1);
 }
 protected void finishGUI() {
   serialPortsChoice.addItemListener(this);
   parallelPortsChoice.addItemListener(this);
   other.addItemListener(this);
   pack();
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

}

 </source>
   
  
 
  

List the ports

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.util.Enumeration; import javax.rum.rumPortIdentifier; /**

* List the ports.
* 
* @author Ian F. Darwin, http://www.darwinsys.ru/
* @version $Id: CommPortLister.java,v 1.4 2004/02/09 03:33:51 ian Exp $
*/

public class CommPortLister {

 /** Simple test program. */
 public static void main(String[] ap) {
   new CommPortLister().list();
 }
 /** Ask the Java Communications API * what ports it thinks it has. */
 protected void list() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list.
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier) pList.nextElement();
     System.out.print("Port " + cpi.getName() + " ");
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       System.out.println("is a Serial Port: " + cpi);
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       System.out.println("is a Parallel Port: " + cpi);
     } else {
       System.out.println("is an Unknown Port: " + cpi);
     }
   }
 }

}

 </source>
   
  
 
  

Open a serial port using Java Communications

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.util.Enumeration; import java.util.HashMap; import javax.rum.rumPort; import javax.rum.rumPortIdentifier; import javax.rum.NoSuchPortException; import javax.rum.ParallelPort; import javax.rum.PortInUseException; import javax.rum.SerialPort; import javax.rum.UnsupportedCommOperationException; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; /**

* Open a serial port using Java Communications.
*
* @author  Ian F. Darwin, http://www.darwinsys.ru/
*/

public class CommPortOpen {

 /** How long to wait for the open to finish up. */
 public static final int TIMEOUTSECONDS = 30;
 /** The baud rate to use. */
 public static final int BAUD = 19200;
 /** The parent JFrame, for the chooser. */
 protected JFrame parent;
 /** The input stream */
 protected BufferedReader is;
 /** The output stream */
 protected PrintStream os;
 /** The chosen Port Identifier */
 CommPortIdentifier thePortID;
 /** The chosen Port itself */
 CommPort thePort;
 public static void main(String[] argv)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new CommPortOpen(null).converse();
   System.exit(0);
 }
 /* Constructor */
 public CommPortOpen(JFrame f)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   
   // Use the PortChooser from before. Pop up the JDialog.
   PortChooser chooser = new PortChooser(null);
   String portName = null;
   do {
     chooser.setVisible(true);
     
     // Dialog done. Get the port name.
     portName = chooser.getSelectedName();
     if (portName == null)
       System.out.println("No port selected. Try again.\n");
   } while (portName == null);
   // Get the CommPortIdentifier.
   thePortID = chooser.getSelectedIdentifier();
   // Now actually open the port.
   // This form of openPort takes an Application Name and a timeout.
   // 
   System.out.println("Trying to open " + thePortID.getName() + "...");
   switch (thePortID.getPortType()) {
   case CommPortIdentifier.PORT_SERIAL:
     thePort = thePortID.open("DarwinSys DataComm",
       TIMEOUTSECONDS * 1000);
     SerialPort myPort = (SerialPort) thePort;
     // set up the serial port
     myPort.setSerialPortParams(BAUD, SerialPort.DATABITS_8,
       SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
     break;
   case CommPortIdentifier.PORT_PARALLEL:
     thePort = thePortID.open("DarwinSys Printing",
       TIMEOUTSECONDS * 1000);
     ParallelPort pPort = (ParallelPort)thePort;
     // Tell API to pick "best available mode" - can fail!
     // myPort.setMode(ParallelPort.LPT_MODE_ANY);
     // Print what the mode is
     int mode = pPort.getMode();
     switch (mode) {
       case ParallelPort.LPT_MODE_ECP:
         System.out.println("Mode is: ECP");
         break;
       case ParallelPort.LPT_MODE_EPP:
         System.out.println("Mode is: EPP");
         break;
       case ParallelPort.LPT_MODE_NIBBLE:
         System.out.println("Mode is: Nibble Mode.");
         break;
       case ParallelPort.LPT_MODE_PS2:
         System.out.println("Mode is: Byte mode.");
         break;
       case ParallelPort.LPT_MODE_SPP:
         System.out.println("Mode is: Compatibility mode.");
         break;
       // ParallelPort.LPT_MODE_ANY is a "set only" mode;
       // tells the API to pick "best mode"; will report the
       // actual mode it selected.
       default:
         throw new IllegalStateException("Parallel mode " + 
           mode + " invalid.");
     }
     break;
   default:  // Neither parallel nor serial??
     throw new IllegalStateException("Unknown port type " + thePortID);
   }
   // Get the input and output streams
   // Printers can be write-only
   try {
     is = new BufferedReader(new InputStreamReader(thePort.getInputStream()));
   } catch (IOException e) {
     System.err.println("Can"t open input stream: write-only");
     is = null;
   }
   os = new PrintStream(thePort.getOutputStream(), true);
 }
 /** This method will be overridden by non-trivial subclasses
  * to hold a conversation. 
  */
 protected void converse() throws IOException {
   System.out.println("Ready to read and write port.");
   // Input/Output code not written -- must subclass.
   // Finally, clean up.
   if (is != null)
     is.close();
   os.close();
 }

} class PortChooser extends JDialog implements ItemListener {

 /** A mapping from names to CommPortIdentifiers. */
 protected HashMap map = new HashMap();
 /** The name of the choice the user made. */
 protected String selectedPortName;
 /** The CommPortIdentifier the user chose. */
 protected CommPortIdentifier selectedPortIdentifier;
 /** The JComboBox for serial ports */
 protected JComboBox serialPortsChoice;
 /** The JComboBox for parallel ports */
 protected JComboBox parallelPortsChoice;
 /** The JComboBox for anything else */
 protected JComboBox other;
 /** The SerialPort object */
 protected SerialPort ttya;
 /** To display the chosen */
 protected JLabel choice;
 /** Padding in the GUI */
 protected final int PAD = 5;
 /** This will be called from either of the JComboBoxen when the
  * user selects any given item.
  */
 public void itemStateChanged(ItemEvent e) {
   // Get the name
   selectedPortName = (String)((JComboBox)e.getSource()).getSelectedItem();
   // Get the given CommPortIdentifier
   selectedPortIdentifier = (CommPortIdentifier)map.get(selectedPortName);
   // Display the name.
   choice.setText(selectedPortName);
 }
 /* The public "getter" to retrieve the chosen port by name. */
 public String getSelectedName() {
   return selectedPortName;
 }
 /* The public "getter" to retrieve the selection by CommPortIdentifier. */
 public CommPortIdentifier getSelectedIdentifier() {
   return selectedPortIdentifier;
 }
 /** A test program to show up this chooser. */
 public static void main(String[] ap) {
   PortChooser c = new PortChooser(null);
   c.setVisible(true);  // blocking wait
   System.out.println("You chose " + c.getSelectedName() +
     " (known by " + c.getSelectedIdentifier() + ").");
   System.exit(0);
 }
 /** Construct a PortChooser --make the GUI and populate the ComboBoxes.
  */
 public PortChooser(JFrame parent) {
   super(parent, "Port Chooser", true);
   makeGUI();
   populate();
   finishGUI();
 }
 /** Build the GUI. You can ignore this for now if you have not
  * yet worked through the GUI chapter. Your mileage may vary.
  */
 protected void makeGUI() {
   Container cp = getContentPane();
   JPanel centerPanel = new JPanel();
   cp.add(BorderLayout.CENTER, centerPanel);
   centerPanel.setLayout(new GridLayout(0,2, PAD, PAD));
   centerPanel.add(new JLabel("Serial Ports", JLabel.RIGHT));
   serialPortsChoice = new JComboBox();
   centerPanel.add(serialPortsChoice);
   serialPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Parallel Ports", JLabel.RIGHT));
   parallelPortsChoice = new JComboBox();
   centerPanel.add(parallelPortsChoice);
   parallelPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Unknown Ports", JLabel.RIGHT));
   other = new JComboBox();
   centerPanel.add(other);
   other.setEnabled(false);
   centerPanel.add(new JLabel("Your choice:", JLabel.RIGHT));
   centerPanel.add(choice = new JLabel());
   JButton okButton;
   cp.add(BorderLayout.SOUTH, okButton = new JButton("OK"));
   okButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       PortChooser.this.dispose();
     }
   });
 }
 /** Populate the ComboBoxes by asking the Java Communications API
  * what ports it has.  Since the initial information comes from
  * a Properties file, it may not exactly reflect your hardware.
  */
 protected void populate() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, putting serial and parallel into ComboBoxes
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier)pList.nextElement();
     // System.out.println("Port " + cpi.getName());
     map.put(cpi.getName(), cpi);
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       serialPortsChoice.setEnabled(true);
       serialPortsChoice.addItem(cpi.getName());
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       parallelPortsChoice.setEnabled(true);
       parallelPortsChoice.addItem(cpi.getName());
     } else {
       other.setEnabled(true);
       other.addItem(cpi.getName());
     }
   }
   serialPortsChoice.setSelectedIndex(-1);
   parallelPortsChoice.setSelectedIndex(-1);
 }
 protected void finishGUI() {
   serialPortsChoice.addItemListener(this);
   parallelPortsChoice.addItemListener(this);
   other.addItemListener(this);
   pack();
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

}

 </source>
   
  
 
  

Port Finder

   <source lang="java">

import java.io.*; import javax.rum.*; import java.util.*; public class Main {

   public static void main(String[] args)
   {
       Enumeration ports = CommPortIdentifier.getPortIdentifiers();
       
       while(ports.hasMoreElements())
       {
           CommPortIdentifier cpi =
                          (CommPortIdentifier)ports.nextElement();
           System.out.println("Port " + cpi.getName());
       }
   }

}

 </source>
   
  
 
  

Port Reader

   <source lang="java">

import java.io.*; import javax.rum.*; import java.util.*; public class PortReader SerialPortEventListener {

 static Enumeration ports;
 static CommPortIdentifier pID;
 InputStream inStream;
 SerialPort serPort;
 public PortReader() throws Exception{
   serPort = (SerialPort) pID.open("PortReader", 2000);
   inStream = serPort.getInputStream();
   serPort.addEventListener(this);
   serPort.notifyOnDataAvailable(true);
   serPort.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1,
       SerialPort.PARITY_NONE);
 }
 public void serialEvent(SerialPortEvent event) {
   switch (event.getEventType()) {
   case SerialPortEvent.BI:
     System.out.println("SerialPortEvent.BI occurred");
   case SerialPortEvent.OE:
     System.out.println("SerialPortEvent.OE occurred");
   case SerialPortEvent.FE:
     System.out.println("SerialPortEvent.FE occurred");
   case SerialPortEvent.PE:
     System.out.println("SerialPortEvent.PE occurred");
   case SerialPortEvent.CD:
     System.out.println("SerialPortEvent.CD occurred");
   case SerialPortEvent.CTS:
     System.out.println("SerialPortEvent.CTS occurred");
   case SerialPortEvent.DSR:
     System.out.println("SerialPortEvent.DSR occurred");
   case SerialPortEvent.RI:
     System.out.println("SerialPortEvent.RI occurred");
   case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
     System.out.println("SerialPortEvent.OUTPUT_BUFFER_EMPTY occurred");
     break;
   case SerialPortEvent.DATA_AVAILABLE:
     System.out.println("SerialPortEvent.DATA_AVAILABLE occurred");
     byte[] readBuffer = new byte[20];
     try {
       while (inStream.available() > 0) {
         int numBytes = inStream.read(readBuffer);
       }
       System.out.print(new String(readBuffer));
     } catch (IOException ioe) {
       System.out.println("Exception " + ioe);
     }
     break;
   }
 }
 public static void main(String[] args) throws Exception{
   ports = CommPortIdentifier.getPortIdentifiers();
   while (ports.hasMoreElements()) {
     pID = (CommPortIdentifier) ports.nextElement();
     System.out.println("Port " + pID.getName());
     if (pID.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       if (pID.getName().equals("COM1")) {
         PortReader pReader = new PortReader();
         System.out.println("COM1 found");
       }
     }
   }
 }

}

 </source>
   
  
 
  

Port Sniffer

   <source lang="java">

import java.io.*; import javax.rum.*; import java.util.*; public class PortSniffer SerialPortEventListener {

   static Enumeration ports;
   static CommPortIdentifier pID;
   InputStream inStream;
   SerialPort serPort;
   
   public PortSniffer() throws Exception
   {
       serPort = (SerialPort)pID.open("PortSniffer",2000);
       inStream = serPort.getInputStream();
       serPort.addEventListener(this);
       
       serPort.notifyOnDataAvailable(true);
       serPort.notifyOnBreakInterrupt(true);
       serPort.notifyOnCarrierDetect(true);
       serPort.notifyOnCTS(true);
       serPort.notifyOnDataAvailable(true);
       serPort.notifyOnDSR(true);
       serPort.notifyOnFramingError(true);
       serPort.notifyOnOutputEmpty(true);
       serPort.notifyOnOverrunError(true);
       serPort.notifyOnParityError(true);
       serPort.notifyOnRingIndicator(true);
       
       serPort.setSerialPortParams(9600, SerialPort.DATABITS_8,
       SerialPort.STOPBITS_1,
       SerialPort.PARITY_NONE);
   }    
   public void serialEvent(SerialPortEvent event)
   {
       switch(event.getEventType())
       {
           case SerialPortEvent.BI:
               System.out.println("SerialPortEvent.BI occurred");
           case SerialPortEvent.OE:
               System.out.println("SerialPortEvent.OE occurred");
           case SerialPortEvent.FE:
               System.out.println("SerialPortEvent.FE occurred");
           case SerialPortEvent.PE:
               System.out.println("SerialPortEvent.PE occurred");
           case SerialPortEvent.CD:
               System.out.println("SerialPortEvent.CD occurred");
           case SerialPortEvent.CTS:
               System.out.println("SerialPortEvent.CTS occurred");
           case SerialPortEvent.DSR:
               System.out.println("SerialPortEvent.DSR occurred");
           case SerialPortEvent.RI:
               System.out.println("SerialPortEvent.RI occurred");
           case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
               System.out.println("SerialPortEvent.OUTPUT_BUFFER_EMPTY occurred");
               break;
           case SerialPortEvent.DATA_AVAILABLE:
               System.out.println("SerialPortEvent.DATA_AVAILABLE occurred");
               byte[] readBuffer = new byte[20];
               
               try
               {
                   while (inStream.available() > 0)
                   {
                       int numBytes = inStream.read(readBuffer);
                   }
                   System.out.print(new String(readBuffer));
                }catch (IOException ioe)
               {
                   System.out.println("Exception " + ioe);
               }
               break;
       }
   }
   
   public static void main(String[] args)throws Exception{
       ports = CommPortIdentifier.getPortIdentifiers();
       
       while(ports.hasMoreElements())
       {
           pID = (CommPortIdentifier)ports.nextElement();
           System.out.println("Port " + pID.getName());
           
           if (pID.getPortType() == CommPortIdentifier.PORT_SERIAL)
           {
               if (pID.getName().equals("COM1"))
               {
                   PortSniffer pSniffer = new PortSniffer();
                   System.out.println("COM1 found");
               }
           }
       }
   }

}

 </source>
   
  
 
  

Port Writer

   <source lang="java">

import java.io.*; import javax.rum.*; import java.util.*; public class PortWriter {

   static Enumeration ports;
   static CommPortIdentifier pID;
   static OutputStream outStream;
   SerialPort serPort;
   static String messageToSend = "message!\n";
   
   public PortWriter() throws Exception{
       serPort = (SerialPort)pID.open("PortWriter",2000);
       outStream = serPort.getOutputStream();
       serPort.setSerialPortParams(9600, SerialPort.DATABITS_8,
       SerialPort.STOPBITS_1,
       SerialPort.PARITY_NONE);
   }    
   
   public static void main(String[] args) throws Exception{
       ports = CommPortIdentifier.getPortIdentifiers();
       
       while(ports.hasMoreElements())
       {
           pID = (CommPortIdentifier)ports.nextElement();
           System.out.println("Port " + pID.getName());
           
           if (pID.getPortType() == CommPortIdentifier.PORT_SERIAL)
           {
               if (pID.getName().equals("COM1"))
               {
                   PortWriter pWriter = new PortWriter();
                   System.out.println("COM1 found");
               }
           }
       }
       outStream.write(messageToSend.getBytes());
   }

}

 </source>
   
  
 
  

Printing a File

   <source lang="java">

import java.io.*; import javax.rum.*; public class PrintFile {

 public static void main(String args[]) throws Exception {
   if (args.length != 2) {
     System.err.println("usage : java PrintFile port file");
     System.err.println("sample: java PrintFile LPT1 sample.prn");
     System.exit(-1);
   }
   String portname = args[0];
   String filename = args[1];
   // Get port
   CommPortIdentifier portId = CommPortIdentifier
       .getPortIdentifier(portname);
   // Open port
   // Requires owner name and timeout
   CommPort port = portId.open("Java Printing", 30000);
   // Setup reading from file
   FileInputStream fis = new FileInputStream(filename);
   BufferedInputStream bis = new BufferedInputStream(fis);
   // Setup output
   OutputStream os = port.getOutputStream();
   BufferedOutputStream bos = new BufferedOutputStream(os);
   int c;
   while ((c = bis.read()) != -1) {
     bos.write(c);
   }
   // Close
   bos.close();
   bis.close();
   port.close();
 }

}

 </source>
   
  
 
  

Querying Available COM Ports

   <source lang="java">

// Install the Java Comm API first. if there is no necessary file, say Dll files, the API // won"t work. import java.util.Enumeration; import javax.rum.*; import java.util.Enumeration; public class ListPorts {

 public static void main(String args[]) {
   Enumeration ports = CommPortIdentifier.getPortIdentifiers();
   while (ports.hasMoreElements()) {
     CommPortIdentifier port = (CommPortIdentifier) ports.nextElement();
     String type;
     switch (port.getPortType()) {
     case CommPortIdentifier.PORT_PARALLEL:
       type = "Parallel";
       break;
     case CommPortIdentifier.PORT_SERIAL:
       type = "Serial";
       break;
     default: /// Shouldn"t happen
       type = "Unknown";
       break;
     }
     System.out.println(port.getName() + ": " + type);
   }
 }

}

 </source>
   
  
 
  

Read from a Serial port, notifying when data arrives

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.util.Enumeration; import java.util.HashMap; import java.util.TooManyListenersException; import javax.rum.rumPort; import javax.rum.rumPortIdentifier; import javax.rum.NoSuchPortException; import javax.rum.ParallelPort; import javax.rum.PortInUseException; import javax.rum.SerialPort; import javax.rum.SerialPortEvent; import javax.rum.SerialPortEventListener; import javax.rum.UnsupportedCommOperationException; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; /**

* Read from a Serial port, notifying when data arrives.
* Simulation of part of an event-logging service.
* @version $Id: SerialReadByEvents.java,v 1.4 2004/04/11 23:50:40 ian Exp $
* @author  Ian F. Darwin, http://www.darwinsys.ru/
*/

public class SerialReadByEvents extends CommPortOpen

 implements SerialPortEventListener {
 public static void main(String[] argv)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new SerialReadByEvents(null).converse();
 }
 /* Constructor */
 public SerialReadByEvents(JFrame f)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   
   super(f);
 }
 /** 
  * Hold the conversation. 
  */
 protected void converse() throws IOException {
   if (!(thePort instanceof SerialPort)) {
     System.err.println("But I wanted a SERIAL port!");
     System.exit(1);
   }
   // Tell the Comm API that we want serial events.
   ((SerialPort)thePort).notifyOnDataAvailable(true);
   try {
     ((SerialPort)thePort).addEventListener(this);
   } catch (TooManyListenersException ev) {
     // "CantHappen" error
     System.err.println("Too many listeners(!) " + ev);
     System.exit(0);
   }
 
   
 }
 public void serialEvent(SerialPortEvent ev) {
   String line;
   try {
     line = is.readLine();
     if (line == null) {
       System.out.println("EOF on serial port.");
       System.exit(0);
     }
     os.println(line);
   } catch (IOException ex) {
     System.err.println("IO Error " + ex);
   }
 }

}

/**

* Open a serial port using Java Communications.
*
* @author  Ian F. Darwin, http://www.darwinsys.ru/
*/

class CommPortOpen {

 /** How long to wait for the open to finish up. */
 public static final int TIMEOUTSECONDS = 30;
 /** The baud rate to use. */
 public static final int BAUD = 19200;
 /** The parent JFrame, for the chooser. */
 protected JFrame parent;
 /** The input stream */
 protected BufferedReader is;
 /** The output stream */
 protected PrintStream os;
 /** The chosen Port Identifier */
 CommPortIdentifier thePortID;
 /** The chosen Port itself */
 CommPort thePort;
 public static void main(String[] argv)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new CommPortOpen(null).converse();
   System.exit(0);
 }
 /* Constructor */
 public CommPortOpen(JFrame f)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   
   // Use the PortChooser from before. Pop up the JDialog.
   PortChooser chooser = new PortChooser(null);
   String portName = null;
   do {
     chooser.setVisible(true);
     
     // Dialog done. Get the port name.
     portName = chooser.getSelectedName();
     if (portName == null)
       System.out.println("No port selected. Try again.\n");
   } while (portName == null);
   // Get the CommPortIdentifier.
   thePortID = chooser.getSelectedIdentifier();
   // Now actually open the port.
   // This form of openPort takes an Application Name and a timeout.
   // 
   System.out.println("Trying to open " + thePortID.getName() + "...");
   switch (thePortID.getPortType()) {
   case CommPortIdentifier.PORT_SERIAL:
     thePort = thePortID.open("DarwinSys DataComm",
       TIMEOUTSECONDS * 1000);
     SerialPort myPort = (SerialPort) thePort;
     // set up the serial port
     myPort.setSerialPortParams(BAUD, SerialPort.DATABITS_8,
       SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
     break;
   case CommPortIdentifier.PORT_PARALLEL:
     thePort = thePortID.open("DarwinSys Printing",
       TIMEOUTSECONDS * 1000);
     ParallelPort pPort = (ParallelPort)thePort;
     // Tell API to pick "best available mode" - can fail!
     // myPort.setMode(ParallelPort.LPT_MODE_ANY);
     // Print what the mode is
     int mode = pPort.getMode();
     switch (mode) {
       case ParallelPort.LPT_MODE_ECP:
         System.out.println("Mode is: ECP");
         break;
       case ParallelPort.LPT_MODE_EPP:
         System.out.println("Mode is: EPP");
         break;
       case ParallelPort.LPT_MODE_NIBBLE:
         System.out.println("Mode is: Nibble Mode.");
         break;
       case ParallelPort.LPT_MODE_PS2:
         System.out.println("Mode is: Byte mode.");
         break;
       case ParallelPort.LPT_MODE_SPP:
         System.out.println("Mode is: Compatibility mode.");
         break;
       // ParallelPort.LPT_MODE_ANY is a "set only" mode;
       // tells the API to pick "best mode"; will report the
       // actual mode it selected.
       default:
         throw new IllegalStateException("Parallel mode " + 
           mode + " invalid.");
     }
     break;
   default:  // Neither parallel nor serial??
     throw new IllegalStateException("Unknown port type " + thePortID);
   }
   // Get the input and output streams
   // Printers can be write-only
   try {
     is = new BufferedReader(new InputStreamReader(thePort.getInputStream()));
   } catch (IOException e) {
     System.err.println("Can"t open input stream: write-only");
     is = null;
   }
   os = new PrintStream(thePort.getOutputStream(), true);
 }
 /** This method will be overridden by non-trivial subclasses
  * to hold a conversation. 
  */
 protected void converse() throws IOException {
   System.out.println("Ready to read and write port.");
   // Input/Output code not written -- must subclass.
   // Finally, clean up.
   if (is != null)
     is.close();
   os.close();
 }

} class PortChooser extends JDialog implements ItemListener {

 /** A mapping from names to CommPortIdentifiers. */
 protected HashMap map = new HashMap();
 /** The name of the choice the user made. */
 protected String selectedPortName;
 /** The CommPortIdentifier the user chose. */
 protected CommPortIdentifier selectedPortIdentifier;
 /** The JComboBox for serial ports */
 protected JComboBox serialPortsChoice;
 /** The JComboBox for parallel ports */
 protected JComboBox parallelPortsChoice;
 /** The JComboBox for anything else */
 protected JComboBox other;
 /** The SerialPort object */
 protected SerialPort ttya;
 /** To display the chosen */
 protected JLabel choice;
 /** Padding in the GUI */
 protected final int PAD = 5;
 /** This will be called from either of the JComboBoxen when the
  * user selects any given item.
  */
 public void itemStateChanged(ItemEvent e) {
   // Get the name
   selectedPortName = (String)((JComboBox)e.getSource()).getSelectedItem();
   // Get the given CommPortIdentifier
   selectedPortIdentifier = (CommPortIdentifier)map.get(selectedPortName);
   // Display the name.
   choice.setText(selectedPortName);
 }
 /* The public "getter" to retrieve the chosen port by name. */
 public String getSelectedName() {
   return selectedPortName;
 }
 /* The public "getter" to retrieve the selection by CommPortIdentifier. */
 public CommPortIdentifier getSelectedIdentifier() {
   return selectedPortIdentifier;
 }
 /** A test program to show up this chooser. */
 public static void main(String[] ap) {
   PortChooser c = new PortChooser(null);
   c.setVisible(true);  // blocking wait
   System.out.println("You chose " + c.getSelectedName() +
     " (known by " + c.getSelectedIdentifier() + ").");
   System.exit(0);
 }
 /** Construct a PortChooser --make the GUI and populate the ComboBoxes.
  */
 public PortChooser(JFrame parent) {
   super(parent, "Port Chooser", true);
   makeGUI();
   populate();
   finishGUI();
 }
 /** Build the GUI. You can ignore this for now if you have not
  * yet worked through the GUI chapter. Your mileage may vary.
  */
 protected void makeGUI() {
   Container cp = getContentPane();
   JPanel centerPanel = new JPanel();
   cp.add(BorderLayout.CENTER, centerPanel);
   centerPanel.setLayout(new GridLayout(0,2, PAD, PAD));
   centerPanel.add(new JLabel("Serial Ports", JLabel.RIGHT));
   serialPortsChoice = new JComboBox();
   centerPanel.add(serialPortsChoice);
   serialPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Parallel Ports", JLabel.RIGHT));
   parallelPortsChoice = new JComboBox();
   centerPanel.add(parallelPortsChoice);
   parallelPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Unknown Ports", JLabel.RIGHT));
   other = new JComboBox();
   centerPanel.add(other);
   other.setEnabled(false);
   centerPanel.add(new JLabel("Your choice:", JLabel.RIGHT));
   centerPanel.add(choice = new JLabel());
   JButton okButton;
   cp.add(BorderLayout.SOUTH, okButton = new JButton("OK"));
   okButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       PortChooser.this.dispose();
     }
   });
 }
 /** Populate the ComboBoxes by asking the Java Communications API
  * what ports it has.  Since the initial information comes from
  * a Properties file, it may not exactly reflect your hardware.
  */
 protected void populate() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, putting serial and parallel into ComboBoxes
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier)pList.nextElement();
     // System.out.println("Port " + cpi.getName());
     map.put(cpi.getName(), cpi);
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       serialPortsChoice.setEnabled(true);
       serialPortsChoice.addItem(cpi.getName());
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       parallelPortsChoice.setEnabled(true);
       parallelPortsChoice.addItem(cpi.getName());
     } else {
       other.setEnabled(true);
       other.addItem(cpi.getName());
     }
   }
   serialPortsChoice.setSelectedIndex(-1);
   parallelPortsChoice.setSelectedIndex(-1);
 }
 protected void finishGUI() {
   serialPortsChoice.addItemListener(this);
   parallelPortsChoice.addItemListener(this);
   other.addItemListener(this);
   pack();
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

}

 </source>
   
  
 
  

Read from multiple Serial ports, notifying when data arrives on any

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Enumeration; import java.util.TooManyListenersException; import java.util.logging.Logger; import javax.rum.rumPortIdentifier; import javax.rum.NoSuchPortException; import javax.rum.PortInUseException; import javax.rum.SerialPort; import javax.rum.SerialPortEvent; import javax.rum.SerialPortEventListener; import javax.rum.UnsupportedCommOperationException; /**

* Read from multiple Serial ports, notifying when data arrives on any.
* 
* @version $Id: SerialLogger.java,v 1.4 2004/03/11 04:09:14 ian Exp $
* @author Ian F. Darwin, http://www.darwinsys.ru/
*/

public class SerialLogger {

 public static void main(String[] argv) throws IOException,
     NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new SerialLogger();
 }
 /* Constructor */
 public SerialLogger() throws IOException, NoSuchPortException,
     PortInUseException, UnsupportedCommOperationException {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, processing only serial ports.
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier) pList.nextElement();
     String name = cpi.getName();
     System.out.print("Port " + name + " ");
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       System.out.println("is a Serial Port: " + cpi);
       SerialPort thePort;
       try {
         thePort = (SerialPort) cpi.open("Logger", 1000);
       } catch (PortInUseException ev) {
         System.err.println("Port in use: " + name);
         continue;
       }
       // Tell the Comm API that we want serial events.
       thePort.notifyOnDataAvailable(true);
       try {
         thePort
             .addEventListener(new Logger(cpi.getName(), thePort));
       } catch (TooManyListenersException ev) {
         // "CantHappen" error
         System.err.println("Too many listeners(!) " + ev);
         System.exit(0);
       }
     }
   }
 }
 /** Handle one port. */
 public class Logger implements SerialPortEventListener {
   String portName;
   SerialPort thePort;
   BufferedReader ifile;
   public Logger(String name, SerialPort port) throws IOException {
     portName = name;
     thePort = port;
     // Make a reader for the input file.
     ifile = new BufferedReader(new InputStreamReader(thePort
         .getInputStream()));
   }
   public void serialEvent(SerialPortEvent ev) {
     String line;
     try {
       line = ifile.readLine();
       if (line == null) {
         System.out.println("EOF on serial port.");
         System.exit(0);
       }
       System.out.println(portName + ": " + line);
     } catch (IOException ex) {
       System.err.println("IO Error " + ex);
     }
   }
 }

}

 </source>
   
  
 
  

Subclasses CommPortOpen and adds send/expect handling for dealing with Hayes-type modems

   <source lang="java">

import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.util.Enumeration; import java.util.HashMap; import javax.rum.rumPort; import javax.rum.rumPortIdentifier; import javax.rum.NoSuchPortException; import javax.rum.ParallelPort; import javax.rum.PortInUseException; import javax.rum.SerialPort; import javax.rum.UnsupportedCommOperationException; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; /**

* Subclasses CommPortOpen and adds send/expect handling for dealing
* with Hayes-type modems.
*
* @author  Ian F. Darwin, http://www.darwinsys.ru/
*/
class CommPortModem extends CommPortOpen {
 /** The last line read from the serial port. */
 protected String response;
 /** A flag to control debugging output. */
 protected boolean debug = true;
 public CommPortModem(JFrame f)
   throws IOException, NoSuchPortException,PortInUseException,
     UnsupportedCommOperationException {
   super(f);
 }
 /** Send a line to a PC-style modem. Send \r\n, regardless of
  * what platform we"re on, instead of using println().
  */
 protected void send(String s) throws IOException {
   if (debug) {
     System.out.print(">>> ");
     System.out.print(s);
     System.out.println();
   }
   os.print(s);
   os.print("\r\n");
   // Expect the modem to echo the command.
   if (!expect(s)) {
     System.err.println("WARNING: Modem did not echo command.");
   }
   // The modem sends an extra blank line by way of a prompt.
   // Here we read and discard it.
   String junk = is.readLine();
   if (junk.length() != 0) {
     System.err.print("Warning: unexpected response: ");
     System.err.println(junk);
   }
 }
 /** Read a line, saving it in "response". 
  * @return true if the expected String is contained in the response, false if not.
  */
 protected boolean expect(String exp) throws IOException {
   response = is.readLine();
   if (debug) {
     System.out.print("<<< ");
     System.out.print(response);
     System.out.println();
   }
   return response.indexOf(exp) >= 0;
 }

} /**

* Dial a phone using the Java Communications Package.
*
* @author  Ian F. Darwin, http://www.darwinsys.ru/
*/

public class CommPortDial extends CommPortModem {

 protected static String number = "000-0000";
 public static void main(String[] ap)
   throws IOException, NoSuchPortException,PortInUseException,
     UnsupportedCommOperationException {
   if (ap.length == 1)
     number = ap[0];
   new CommPortDial().converse();
   System.exit(0);
 }
 public CommPortDial() 
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   super(null);
 }
 protected void converse() throws IOException {
   String resp;    // the modem response.
   // Send the reset command
   send("ATZ");
   expect("OK");
   send("ATDT" + number);
   expect("OK");
   try {
     Thread.sleep(5000);
   } catch (InterruptedException e) {
     // nothing to do
   }
   is.close();
   os.close();
 }

} class CommPortOpen {

 /** How long to wait for the open to finish up. */
 public static final int TIMEOUTSECONDS = 30;
 /** The baud rate to use. */
 public static final int BAUD = 19200;
 /** The parent JFrame, for the chooser. */
 protected JFrame parent;
 /** The input stream */
 protected BufferedReader is;
 /** The output stream */
 protected PrintStream os;
 /** The chosen Port Identifier */
 CommPortIdentifier thePortID;
 /** The chosen Port itself */
 CommPort thePort;
 public static void main(String[] argv)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new CommPortOpen(null).converse();
   System.exit(0);
 }
 /* Constructor */
 public CommPortOpen(JFrame f)
   throws IOException, NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   
   // Use the PortChooser from before. Pop up the JDialog.
   PortChooser chooser = new PortChooser(null);
   String portName = null;
   do {
     chooser.setVisible(true);
     
     // Dialog done. Get the port name.
     portName = chooser.getSelectedName();
     if (portName == null)
       System.out.println("No port selected. Try again.\n");
   } while (portName == null);
   // Get the CommPortIdentifier.
   thePortID = chooser.getSelectedIdentifier();
   // Now actually open the port.
   // This form of openPort takes an Application Name and a timeout.
   // 
   System.out.println("Trying to open " + thePortID.getName() + "...");
   switch (thePortID.getPortType()) {
   case CommPortIdentifier.PORT_SERIAL:
     thePort = thePortID.open("DarwinSys DataComm",
       TIMEOUTSECONDS * 1000);
     SerialPort myPort = (SerialPort) thePort;
     // set up the serial port
     myPort.setSerialPortParams(BAUD, SerialPort.DATABITS_8,
       SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
     break;
   case CommPortIdentifier.PORT_PARALLEL:
     thePort = thePortID.open("DarwinSys Printing",
       TIMEOUTSECONDS * 1000);
     ParallelPort pPort = (ParallelPort)thePort;
     // Tell API to pick "best available mode" - can fail!
     // myPort.setMode(ParallelPort.LPT_MODE_ANY);
     // Print what the mode is
     int mode = pPort.getMode();
     switch (mode) {
       case ParallelPort.LPT_MODE_ECP:
         System.out.println("Mode is: ECP");
         break;
       case ParallelPort.LPT_MODE_EPP:
         System.out.println("Mode is: EPP");
         break;
       case ParallelPort.LPT_MODE_NIBBLE:
         System.out.println("Mode is: Nibble Mode.");
         break;
       case ParallelPort.LPT_MODE_PS2:
         System.out.println("Mode is: Byte mode.");
         break;
       case ParallelPort.LPT_MODE_SPP:
         System.out.println("Mode is: Compatibility mode.");
         break;
       // ParallelPort.LPT_MODE_ANY is a "set only" mode;
       // tells the API to pick "best mode"; will report the
       // actual mode it selected.
       default:
         throw new IllegalStateException("Parallel mode " + 
           mode + " invalid.");
     }
     break;
   default:  // Neither parallel nor serial??
     throw new IllegalStateException("Unknown port type " + thePortID);
   }
   // Get the input and output streams
   // Printers can be write-only
   try {
     is = new BufferedReader(new InputStreamReader(thePort.getInputStream()));
   } catch (IOException e) {
     System.err.println("Can"t open input stream: write-only");
     is = null;
   }
   os = new PrintStream(thePort.getOutputStream(), true);
 }
 /** This method will be overridden by non-trivial subclasses
  * to hold a conversation. 
  */
 protected void converse() throws IOException {
   System.out.println("Ready to read and write port.");
   // Input/Output code not written -- must subclass.
   // Finally, clean up.
   if (is != null)
     is.close();
   os.close();
 }

} class PortChooser extends JDialog implements ItemListener {

 /** A mapping from names to CommPortIdentifiers. */
 protected HashMap map = new HashMap();
 /** The name of the choice the user made. */
 protected String selectedPortName;
 /** The CommPortIdentifier the user chose. */
 protected CommPortIdentifier selectedPortIdentifier;
 /** The JComboBox for serial ports */
 protected JComboBox serialPortsChoice;
 /** The JComboBox for parallel ports */
 protected JComboBox parallelPortsChoice;
 /** The JComboBox for anything else */
 protected JComboBox other;
 /** The SerialPort object */
 protected SerialPort ttya;
 /** To display the chosen */
 protected JLabel choice;
 /** Padding in the GUI */
 protected final int PAD = 5;
 /** This will be called from either of the JComboBoxen when the
  * user selects any given item.
  */
 public void itemStateChanged(ItemEvent e) {
   // Get the name
   selectedPortName = (String)((JComboBox)e.getSource()).getSelectedItem();
   // Get the given CommPortIdentifier
   selectedPortIdentifier = (CommPortIdentifier)map.get(selectedPortName);
   // Display the name.
   choice.setText(selectedPortName);
 }
 /* The public "getter" to retrieve the chosen port by name. */
 public String getSelectedName() {
   return selectedPortName;
 }
 /* The public "getter" to retrieve the selection by CommPortIdentifier. */
 public CommPortIdentifier getSelectedIdentifier() {
   return selectedPortIdentifier;
 }
 /** A test program to show up this chooser. */
 public static void main(String[] ap) {
   PortChooser c = new PortChooser(null);
   c.setVisible(true);  // blocking wait
   System.out.println("You chose " + c.getSelectedName() +
     " (known by " + c.getSelectedIdentifier() + ").");
   System.exit(0);
 }
 /** Construct a PortChooser --make the GUI and populate the ComboBoxes.
  */
 public PortChooser(JFrame parent) {
   super(parent, "Port Chooser", true);
   makeGUI();
   populate();
   finishGUI();
 }
 /** Build the GUI. You can ignore this for now if you have not
  * yet worked through the GUI chapter. Your mileage may vary.
  */
 protected void makeGUI() {
   Container cp = getContentPane();
   JPanel centerPanel = new JPanel();
   cp.add(BorderLayout.CENTER, centerPanel);
   centerPanel.setLayout(new GridLayout(0,2, PAD, PAD));
   centerPanel.add(new JLabel("Serial Ports", JLabel.RIGHT));
   serialPortsChoice = new JComboBox();
   centerPanel.add(serialPortsChoice);
   serialPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Parallel Ports", JLabel.RIGHT));
   parallelPortsChoice = new JComboBox();
   centerPanel.add(parallelPortsChoice);
   parallelPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Unknown Ports", JLabel.RIGHT));
   other = new JComboBox();
   centerPanel.add(other);
   other.setEnabled(false);
   centerPanel.add(new JLabel("Your choice:", JLabel.RIGHT));
   centerPanel.add(choice = new JLabel());
   JButton okButton;
   cp.add(BorderLayout.SOUTH, okButton = new JButton("OK"));
   okButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       PortChooser.this.dispose();
     }
   });
 }
 /** Populate the ComboBoxes by asking the Java Communications API
  * what ports it has.  Since the initial information comes from
  * a Properties file, it may not exactly reflect your hardware.
  */
 protected void populate() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, putting serial and parallel into ComboBoxes
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier)pList.nextElement();
     // System.out.println("Port " + cpi.getName());
     map.put(cpi.getName(), cpi);
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       serialPortsChoice.setEnabled(true);
       serialPortsChoice.addItem(cpi.getName());
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       parallelPortsChoice.setEnabled(true);
       parallelPortsChoice.addItem(cpi.getName());
     } else {
       other.setEnabled(true);
       other.addItem(cpi.getName());
     }
   }
   serialPortsChoice.setSelectedIndex(-1);
   parallelPortsChoice.setSelectedIndex(-1);
 }
 protected void finishGUI() {
   serialPortsChoice.addItemListener(this);
   parallelPortsChoice.addItemListener(this);
   other.addItemListener(this);
   pack();
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

}

 </source>
   
  
 
  

This program tries to do I/O in each direction using a separate Thread

   <source lang="java">

/*

* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* 
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java 
* language and environment is gratefully acknowledged.
* 
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemEvent; import java.awt.event.ItemListener; import java.io.BufferedReader; import java.io.DataInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.PrintStream; import java.util.Enumeration; import java.util.HashMap; import javax.rum.rumPort; import javax.rum.rumPortIdentifier; import javax.rum.NoSuchPortException; import javax.rum.ParallelPort; import javax.rum.PortInUseException; import javax.rum.SerialPort; import javax.rum.UnsupportedCommOperationException; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JDialog; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel;

/**

* This program tries to do I/O in each direction using a separate Thread.
* 
* @author Ian F. Darwin, http://www.darwinsys.ru/
*/

public class CommPortThreaded extends CommPortOpen {

 public static void main(String[] ap) throws IOException,
     NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   CommPortThreaded cp;
   try {
     cp = new CommPortThreaded();
     cp.converse();
   } catch (Exception e) {
     System.err.println("You lose!");
     System.err.println(e);
   }
 }
 public CommPortThreaded() throws IOException, NoSuchPortException,
     PortInUseException, UnsupportedCommOperationException {
   super(null);
 }
 /**
  * This version of converse() just starts a Thread in each direction.
  */
 protected void converse() throws IOException {
   String resp; // the modem response.
   new DataThread(is, System.out).start();
   new DataThread(new DataInputStream(System.in), os).start();
 }
 /** This inner class handles one side of a conversation. */
 class DataThread extends Thread {
   BufferedReader inStream;
   PrintStream pStream;
   /** Construct this object */
   DataThread(InputStream is, PrintStream os) {
     inStream = new BufferedReader(new InputStreamReader(is));
     pStream = os;
   }
   DataThread(BufferedReader is, PrintStream os) {
     inStream = is;
     pStream = os;
   }
   /** A Thread"s run method does the work. */
   public void run() {
     byte ch = 0;
     try {
       while ((ch = (byte) inStream.read()) != -1)
         pStream.print((char) ch);
     } catch (IOException e) {
       System.err.println("Input or output error: " + e);
       return;
     }
   }
 }

} /**

* Open a serial port using Java Communications.
* 
* @author Ian F. Darwin, http://www.darwinsys.ru/
*/

class CommPortOpen {

 /** How long to wait for the open to finish up. */
 public static final int TIMEOUTSECONDS = 30;
 /** The baud rate to use. */
 public static final int BAUD = 19200;
 /** The parent JFrame, for the chooser. */
 protected JFrame parent;
 /** The input stream */
 protected BufferedReader is;
 /** The output stream */
 protected PrintStream os;
 /** The chosen Port Identifier */
 CommPortIdentifier thePortID;
 /** The chosen Port itself */
 CommPort thePort;
 public static void main(String[] argv) throws IOException,
     NoSuchPortException, PortInUseException,
     UnsupportedCommOperationException {
   new CommPortOpen(null).converse();
   System.exit(0);
 }
 /* Constructor */
 public CommPortOpen(JFrame f) throws IOException, NoSuchPortException,
     PortInUseException, UnsupportedCommOperationException {
   // Use the PortChooser from before. Pop up the JDialog.
   PortChooser chooser = new PortChooser(null);
   String portName = null;
   do {
     chooser.setVisible(true);
     // Dialog done. Get the port name.
     portName = chooser.getSelectedName();
     if (portName == null)
       System.out.println("No port selected. Try again.\n");
   } while (portName == null);
   // Get the CommPortIdentifier.
   thePortID = chooser.getSelectedIdentifier();
   // Now actually open the port.
   // This form of openPort takes an Application Name and a timeout.
   // 
   System.out.println("Trying to open " + thePortID.getName() + "...");
   switch (thePortID.getPortType()) {
   case CommPortIdentifier.PORT_SERIAL:
     thePort = thePortID.open("DarwinSys DataComm",
         TIMEOUTSECONDS * 1000);
     SerialPort myPort = (SerialPort) thePort;
     // set up the serial port
     myPort.setSerialPortParams(BAUD, SerialPort.DATABITS_8,
         SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
     break;
   case CommPortIdentifier.PORT_PARALLEL:
     thePort = thePortID.open("DarwinSys Printing",
         TIMEOUTSECONDS * 1000);
     ParallelPort pPort = (ParallelPort) thePort;
     // Tell API to pick "best available mode" - can fail!
     // myPort.setMode(ParallelPort.LPT_MODE_ANY);
     // Print what the mode is
     int mode = pPort.getMode();
     switch (mode) {
     case ParallelPort.LPT_MODE_ECP:
       System.out.println("Mode is: ECP");
       break;
     case ParallelPort.LPT_MODE_EPP:
       System.out.println("Mode is: EPP");
       break;
     case ParallelPort.LPT_MODE_NIBBLE:
       System.out.println("Mode is: Nibble Mode.");
       break;
     case ParallelPort.LPT_MODE_PS2:
       System.out.println("Mode is: Byte mode.");
       break;
     case ParallelPort.LPT_MODE_SPP:
       System.out.println("Mode is: Compatibility mode.");
       break;
     // ParallelPort.LPT_MODE_ANY is a "set only" mode;
     // tells the API to pick "best mode"; will report the
     // actual mode it selected.
     default:
       throw new IllegalStateException("Parallel mode " + mode
           + " invalid.");
     }
     break;
   default: // Neither parallel nor serial??
     throw new IllegalStateException("Unknown port type " + thePortID);
   }
   // Get the input and output streams
   // Printers can be write-only
   try {
     is = new BufferedReader(new InputStreamReader(thePort
         .getInputStream()));
   } catch (IOException e) {
     System.err.println("Can"t open input stream: write-only");
     is = null;
   }
   os = new PrintStream(thePort.getOutputStream(), true);
 }
 /**
  * This method will be overridden by non-trivial subclasses to hold a
  * conversation.
  */
 protected void converse() throws IOException {
   System.out.println("Ready to read and write port.");
   // Input/Output code not written -- must subclass.
   // Finally, clean up.
   if (is != null)
     is.close();
   os.close();
 }

}

class PortChooser extends JDialog implements ItemListener {

 /** A mapping from names to CommPortIdentifiers. */
 protected HashMap map = new HashMap();
 /** The name of the choice the user made. */
 protected String selectedPortName;
 /** The CommPortIdentifier the user chose. */
 protected CommPortIdentifier selectedPortIdentifier;
 /** The JComboBox for serial ports */
 protected JComboBox serialPortsChoice;
 /** The JComboBox for parallel ports */
 protected JComboBox parallelPortsChoice;
 /** The JComboBox for anything else */
 protected JComboBox other;
 /** The SerialPort object */
 protected SerialPort ttya;
 /** To display the chosen */
 protected JLabel choice;
 /** Padding in the GUI */
 protected final int PAD = 5;
 /** This will be called from either of the JComboBoxen when the
  * user selects any given item.
  */
 public void itemStateChanged(ItemEvent e) {
   // Get the name
   selectedPortName = (String)((JComboBox)e.getSource()).getSelectedItem();
   // Get the given CommPortIdentifier
   selectedPortIdentifier = (CommPortIdentifier)map.get(selectedPortName);
   // Display the name.
   choice.setText(selectedPortName);
 }
 /* The public "getter" to retrieve the chosen port by name. */
 public String getSelectedName() {
   return selectedPortName;
 }
 /* The public "getter" to retrieve the selection by CommPortIdentifier. */
 public CommPortIdentifier getSelectedIdentifier() {
   return selectedPortIdentifier;
 }
 /** A test program to show up this chooser. */
 public static void main(String[] ap) {
   PortChooser c = new PortChooser(null);
   c.setVisible(true);  // blocking wait
   System.out.println("You chose " + c.getSelectedName() +
     " (known by " + c.getSelectedIdentifier() + ").");
   System.exit(0);
 }
 /** Construct a PortChooser --make the GUI and populate the ComboBoxes.
  */
 public PortChooser(JFrame parent) {
   super(parent, "Port Chooser", true);
   makeGUI();
   populate();
   finishGUI();
 }
 /** Build the GUI. You can ignore this for now if you have not
  * yet worked through the GUI chapter. Your mileage may vary.
  */
 protected void makeGUI() {
   Container cp = getContentPane();
   JPanel centerPanel = new JPanel();
   cp.add(BorderLayout.CENTER, centerPanel);
   centerPanel.setLayout(new GridLayout(0,2, PAD, PAD));
   centerPanel.add(new JLabel("Serial Ports", JLabel.RIGHT));
   serialPortsChoice = new JComboBox();
   centerPanel.add(serialPortsChoice);
   serialPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Parallel Ports", JLabel.RIGHT));
   parallelPortsChoice = new JComboBox();
   centerPanel.add(parallelPortsChoice);
   parallelPortsChoice.setEnabled(false);
   centerPanel.add(new JLabel("Unknown Ports", JLabel.RIGHT));
   other = new JComboBox();
   centerPanel.add(other);
   other.setEnabled(false);
   centerPanel.add(new JLabel("Your choice:", JLabel.RIGHT));
   centerPanel.add(choice = new JLabel());
   JButton okButton;
   cp.add(BorderLayout.SOUTH, okButton = new JButton("OK"));
   okButton.addActionListener(new ActionListener() {
     public void actionPerformed(ActionEvent e) {
       PortChooser.this.dispose();
     }
   });
 }
 /** Populate the ComboBoxes by asking the Java Communications API
  * what ports it has.  Since the initial information comes from
  * a Properties file, it may not exactly reflect your hardware.
  */
 protected void populate() {
   // get list of ports available on this particular computer,
   // by calling static method in CommPortIdentifier.
   Enumeration pList = CommPortIdentifier.getPortIdentifiers();
   // Process the list, putting serial and parallel into ComboBoxes
   while (pList.hasMoreElements()) {
     CommPortIdentifier cpi = (CommPortIdentifier)pList.nextElement();
     // System.out.println("Port " + cpi.getName());
     map.put(cpi.getName(), cpi);
     if (cpi.getPortType() == CommPortIdentifier.PORT_SERIAL) {
       serialPortsChoice.setEnabled(true);
       serialPortsChoice.addItem(cpi.getName());
     } else if (cpi.getPortType() == CommPortIdentifier.PORT_PARALLEL) {
       parallelPortsChoice.setEnabled(true);
       parallelPortsChoice.addItem(cpi.getName());
     } else {
       other.setEnabled(true);
       other.addItem(cpi.getName());
     }
   }
   serialPortsChoice.setSelectedIndex(-1);
   parallelPortsChoice.setSelectedIndex(-1);
 }
 protected void finishGUI() {
   serialPortsChoice.addItemListener(this);
   parallelPortsChoice.addItemListener(this);
   other.addItemListener(this);
   pack();
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 }

}

 </source>