Thread: interaction between serial rxtx and swing

Hi I'm a beginner in java, I'm trying to make a simple program to show available serial ports in a Jmenu
I have separate classes:

- the serialCommunication class
- the gui class
- the main class

the serialCommunication class contains the method getAvailablePorts(), so If I call it from the main class, I get the com ports list and it works
the gui class contains the methods to build the jframe and the jmenu, so when I call the method gui.build() from the main class everything works fine


now, I'd like to list the available serial ports in a Jmenu, and have the ports list rescanned every time the menu is opened but I can't call the method getAvailablePorts() from the gui class because I get an error "cannot make a static reference to the non static method..."
I think this is because the serial port instance exists only in the main class, so I can't call its methods from another class.
Could you please point me in the right direction...

here is the whole serial communication class:

import gnu.io.CommPort; import gnu.io.CommPortIdentifier; import gnu.io.SerialPort; import gnu.io.SerialPortEvent; import gnu.io.SerialPortEventListener; import java.util.*; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.Enumeration;       public class SerialCommunication implements SerialPortEventListener {   InputStream input; OutputStream output; CommPort commPort; byte buffer[] = new byte[32768]; int bufferIndex; int bufferLast; public int[] dataIn = new int[20]; public byte[] dataOut = new byte [90]; int counter = 0; int rate; int parity; int databits; int stopbits; boolean monitor = true; MessageConsumer consumer;   boolean Reply1Received = false; boolean Reply2Received = false; boolean Reply3Received = false; boolean Reply4Received = false; boolean Reply5Received = false; boolean _allowed = false;	byte[] _key = new byte[2];	int _verifyCount = 0;	int _serialCount = 0;	byte[] _inBuffer = new byte[6];	int _checkSum = 0;  	byte InByte1 = 0;	byte InByte2 = 0;	byte InByte3 = 0;	byte InByte4 = 0;  	byte[] reply1 = new byte[4];	byte[] reply2 = new byte[4];	byte[] reply3 = new byte[4];	byte[] reply4 = new byte[4];	byte[] reply5 = new byte[4];   public SerialCommunication() { super(); }   void connect ( String portName ) throws Exception   { _key[0] = 1; _key[1] = -2;     CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName); if ( portIdentifier.isCurrentlyOwned() ) { System.out.println("Error: Port is currently in use"); } else { commPort = portIdentifier.open(this.getClass().getName(),1000);   if ( commPort instanceof SerialPort ) { SerialPort serialPort = (SerialPort) commPort; serialPort.setSerialPortParams(115200,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);     input = serialPort.getInputStream();	output = serialPort.getOutputStream();      	serialPort.addEventListener(this);	serialPort.notifyOnDataAvailable(true);   } else { System.out.println("Error: Only serial ports are handled"); } } } public void addListener(MessageConsumer consumer) { this.consumer = consumer; } public void dispose(){	try{	if (input != null) input.close();	if (output != null) output.close();	}	catch	(Exception e){e.printStackTrace();  	}	try{	if (commPort != null) commPort.close();	}	catch (Exception e)	{e.printStackTrace();  	}     }       synchronized public void serialEvent(SerialPortEvent serialEvent) {     if (serialEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {   try { while (input.available() > 0) {   synchronized (buffer) { if (bufferLast == buffer.length) { byte temp[] = new byte[bufferLast << 1]; System.arraycopy(buffer, 0, temp, 0, bufferLast); buffer = temp; }     int inByte = input.read(); feed(inByte); //System.out.println(inByte); // uncomment for testing   if (this.consumer != null) this.consumer.message("" + (char) input.read());     } }     } catch (IOException e) {   System.out.println("no!"); } catch (Exception e) { } }}         public int read() { if (bufferIndex == bufferLast) return -1;   synchronized (buffer) { int outgoing = buffer[bufferIndex++] & 0xff; if (bufferIndex == bufferLast) { // rewind bufferIndex = 0; bufferLast = 0; } return outgoing; } }   public char readChar() { if (bufferIndex == bufferLast) return (char)(-1); return (char) read(); }   public void write(int what) { try { output.write(what & 0xff); output.flush();   } catch (Exception e) { // null pointer or serial port dead //errorMessage("write", e); } }     public void write(byte bytes[]) { try { output.write(bytes); output.flush();   } catch (Exception e) { e.printStackTrace(); } }   /** */ /* public static class SerialWriter implements Runnable { OutputStream out;   public SerialWriter ( OutputStream out ) { this.out = out; }   public void run () { try { int c = 0; while ( ( c = System.in.read()) > -1 ) { this.out.write(c); } } catch ( IOException e ) { e.printStackTrace(); System.exit(-1); } } }*/   public List<String> getAvailablePorts() {   List<String> list = new ArrayList<String>();   Enumeration portList = CommPortIdentifier.getPortIdentifiers();   while (portList.hasMoreElements()) { CommPortIdentifier portId = (CommPortIdentifier) portList.nextElement(); if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) { list.add(portId.getName()); } }   return list;	}   void feed(int _inByte){      	if(_allowed == false){	if(_inByte == _key[_verifyCount]){ _verifyCount++;	if(_verifyCount > 1){_allowed = true;_verifyCount = 0;}	}else{_verifyCount = 0;}}  	else{_inBuffer[_serialCount] = (byte)_inByte; if(_serialCount < 5){ _checkSum += _inByte; } _serialCount++; if(_serialCount > 5){ if(_inBuffer[5] == _checkSum){_Process(_inBuffer);} else{_BadSerialEvent();} _allowed = false; _checkSum = 0; _serialCount = 0;}}              	}      	void _Process(byte[] _input ){   InByte1 = _input[1]; InByte2 = _input[2]; InByte3 = _input[3]; InByte4 = _input[4];    	switch (_input[0]){ case 0: _SaveReply1(InByte1,InByte2,InByte3,InByte4); Reply1Received = true; break;   case 1:	_SaveReply2(InByte1,InByte2,InByte3,InByte4);	Reply2Received = true;  	break;  	case 2:	_SaveReply3(InByte1,InByte2,InByte3,InByte4);	Reply3Received = true;	break;  	case 3:	_SaveReply4(InByte1,InByte2,InByte3,InByte4);	Reply4Received = true;	break;  	case 4:	_SaveReply5(InByte1,InByte2,InByte3,InByte4);	Reply5Received = true;	break;  	}  	}      	void _BadSerialEvent(){              	}    	public void SendFunction1(int byte1, int byte2, int byte3, int byte4){  	//create _checksum	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(0);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write((byte)_checkSum);	//System.out.println((byte)_checkSum);	}  	public void SendFunction2(int byte1, int byte2, int byte3, int byte4){  	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(1);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write(_checkSum);  	}  	public void SendFunction3(int byte1, int byte2, int byte3, int byte4){  	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(2);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write(_checkSum);  	}  	public void SendFunction4(int byte1, int byte2, int byte3, int byte4){  	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(3);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write(_checkSum);  	}  	public void SendFunction5(int byte1, int byte2, int byte3, int byte4){  	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(4);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write(_checkSum);	}      	void _SaveReply1(byte byte1, byte byte2, byte byte3, byte byte4){  	reply1[0] = byte1;	reply1[1] = byte2;	reply1[2] = byte3;	reply1[3] = byte4;  	}   void _SaveReply2(byte byte1, byte byte2, byte byte3, byte byte4){  	reply2[0] = byte1;	reply2[1] = byte2;	reply2[2] = byte3;	reply2[3] = byte4;  	}   void _SaveReply3(byte byte1, byte byte2, byte byte3, byte byte4){  	reply3[0] = byte1;	reply3[1] = byte2;	reply3[2] = byte3;	reply3[3] = byte4;   }   void _SaveReply4(byte byte1, byte byte2, byte byte3, byte byte4){  	reply4[0] = byte1;	reply4[1] = byte2;	reply4[2] = byte3;	reply4[3] = byte4;   }   void _SaveReply5(byte byte1, byte byte2, byte byte3, byte byte4){  	reply5[0] = byte1;	reply5[1] = byte2;	reply5[2] = byte3;	reply5[3] = byte4;   }   public void AskDataSet1(int byte1, int byte2, int byte3, int byte4){  	//create _checksum	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(5);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write((byte)_checkSum);	Reply1Received = false;	//System.out.println((byte)_checkSum);  	}   public void AskDataSet2(int byte1, int byte2, int byte3, int byte4){  	//create _checksum	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(6);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write((byte)_checkSum);	Reply2Received = false;	//System.out.println((byte)_checkSum);   }   public void AskDataSet3(int byte1, int byte2, int byte3, int byte4){  	//create _checksum	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(7);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write((byte)_checkSum);	Reply3Received = false;	//System.out.println((byte)_checkSum);   }   public void AskDataSet4(int byte1, int byte2, int byte3, int byte4){  	//create _checksum	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(8);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write((byte)_checkSum);	Reply4Received = false;	//System.out.println((byte)_checkSum);   }   public void AskDataSet5(int byte1, int byte2, int byte3, int byte4){  	//create _checksum	_checkSum = byte1 + byte2 + byte3 + byte4;  	write(_key);	write(9);	write((byte)byte1);	write((byte)byte2);	write((byte)byte3);	write((byte)byte4);	write((byte)_checkSum);	Reply5Received = false;	//System.out.println((byte)_checkSum);   }   }

and here is the gui builder class :

  import javax.swing.*; import java.awt.*; import java.util.*; import java.awt.event.*; import eu.hansolo.steelseries.gauges.*; import org.*;     public class guiPanel {       JPanel mainPanel; ArrayList<JTextField> textFieldList; JFrame theFrame; ArrayList<JLabel> rpmLabels; ArrayList<JLabel> tpsLabels; ArrayList<JRadioButtonMenuItem> comRadioButtons; int rpmMax = 0; int tpsMax = 0;   JMenuBar menuBar; JMenu serialMenu, submenu;   ArrayList<String> comPortsList;   ActionListener serialMenuListener;               public void refreshComPorts(Object[] comPortsObj){  	comPortsList = new ArrayList<String>();	comRadioButtons = new ArrayList<JRadioButtonMenuItem>();	ButtonGroup group = new ButtonGroup(); //	System.out.println(port.getAvailablePorts());	if(comPortsObj != null){ for (int i = 0; i < comPortsObj.length; i++){	comPortsList.add((String)comPortsObj[i]);  	JRadioButtonMenuItem e = new JRadioButtonMenuItem(comPortsList.get(i));	comRadioButtons.add(e);	//group.add(e);	serialMenu.add(e); }  	//JMenuItem comList = new JMenuItem("Com Port");	//item.addActionListener(actionListener);           //System.out.println(comPortsList);	}           }           public void buildGui() {  	/******************************************************set look and feel***********************************************/  	try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch(Exception e) { System.out.println("Error setting native LAF: " + e); }          	theFrame = new JFrame("Injection Manager"); //create main window	theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //close operation setup	BorderLayout layout = new BorderLayout(); //create border layout used in background jpanel	JPanel background = new JPanel(layout); //create background jpanel	background.setBorder(BorderFactory.createEmptyBorder(10,10,10,10)); //set background borders distance from the main window borders    	textFieldList = new ArrayList<JTextField>(); //arraylist of textfields for the table values	rpmLabels = new ArrayList<JLabel>(); //arraylist of Jlabels for rpm grid steps	tpsLabels = new ArrayList<JLabel>(); //arraylist of jlabels for tps grid steps  	theFrame.getContentPane().add(background); //put the background jpanel over the main window theFrame	GridLayout grid = new GridLayout(13,13); //create grid layout to organize the textfields	grid.setVgap(8); //set the distance top - bottom of the cells	grid.setHgap(8); //set the distance right - left of the cells	mainPanel = new JPanel(grid); //create mainpanel, a new jpanel with the grid layout	background.add(BorderLayout.CENTER, mainPanel); //add mainpanel to background jpanel in the center position  	rpmMax = 8000;	tpsMax = 930;     /***************************************************************************text fields***********************************************/  	for(int f = 11;f >= 0; f --){	String labelTpsVal = Integer.toString(tpsMax / 11 * f) ;	//System.out.println(labelTpsVal);	JLabel TpsLab = new JLabel(labelTpsVal);	tpsLabels.add(TpsLab);	mainPanel.add(TpsLab);  	for (int i = 0; i < 12; i++){	JTextField t = new JTextField(2);	textFieldList.add(t);	mainPanel.add(t);	}	}    	//JLabel emptyLabel = new JLabel(" ");	//mainPanel.add(emptyLabel);  	JLabel spaceLab = new JLabel(" ");	rpmLabels.add(spaceLab);	mainPanel.add(spaceLab);        	for(int j = 0;j < 12; j ++){	String labelRpmVal = Integer.toString(rpmMax / 11 * j);	//System.out.println(labelRpmVal);	JLabel RpmLab = new JLabel(labelRpmVal);	rpmLabels.add(RpmLab);	mainPanel.add(RpmLab);	}     /*********************************************************************************************menu bar***************************/      	menuBar = new JMenuBar();	serialMenu = new JMenu("Serial Port");  	menuBar.add(serialMenu);	theFrame.setJMenuBar(menuBar);  	//JMenuItem comPort = new JMenu("Com Port");	serialMenu.addActionListener(serialMenuListener);	//menu.add(comPort);    	/*JMenuItem comList = new JMenuItem("Com Port");	//item.addActionListener(actionListener);	comPort.add(comList);	*/              	Box buttonBox = new Box(BoxLayout.Y_AXIS);  	JButton fetch = new JButton ("Fetch");	//fetch.addActionListener(new FetchListener());	buttonBox.add(fetch);      	JButton send = new JButton ("Send");	//send.addActionListener(new SendListener());	buttonBox.add(send);  	buttonBox.setBorder(BorderFactory.createEmptyBorder(10,10,10,10));	background.add(BorderLayout.EAST, buttonBox);              	theFrame.setBounds(300,300,300,300);	theFrame.pack();	theFrame.setVisible(true);     }     }

and here the main class :

public class mainClass {      	public static void main(String[] args) throws Exception { SerialCommunication port = new SerialCommunication();   guiPanel gui = new guiPanel(); gui.buildGui();} }

if I add this line "System.out.println(port.getAvailablePorts()); " within the gui class, I get the error "port cannot be resolved" so I can't access the serialCommunication instance variable "port" from that class or other classes.
Which is the correct way to do this?
Do the classes need to be in the same package?

ok, I declared "port" in the gui class, and it works, thanks.
Just one more question...if I have two or more classes that need to "use" the same serialcommunication class, do I need to instantiate a serialCommunication object in each class?

nice ques to learn from u all