My issue lies in my DocumentLister AreaListener. I can't seem to figure out how to pass in the text the user enters into one of the JTextAreas for my conversions and return it to the other JTextArea.
The goal of the program is to take in a user entered Roman or Arabic Number in one of the fields, convert it and return the value of the conversion to the other field in real time.
My GUI and conversion methods work, I just can't seem to wrap my head around obtaining that string from the user and printing it in real time.
public class ArabicToRomanGUI_Hard extends JFrame
{
private static final long serialVersionUID = 1L;
JPanel panel = new JPanel();
//constructor to add text fields to frame
public ArabicToRomanGUI_Hard()
{
JTextArea left = new JTextArea(10, 20);
JTextArea right = new JTextArea(10, 20);
setLayout(new GridLayout(1, 2));
add(new JScrollPane(left));
add(new JScrollPane(right));
MirrorDocument leftDoc = new MirrorDocument();
MirrorDocument rightDoc = new MirrorDocument();
left.setDocument(leftDoc);
right.setDocument(rightDoc);
leftDoc.addDocumentListener(new DocumentHandler(rightDoc));
rightDoc.addDocumentListener(new DocumentHandler(leftDoc));
leftDoc.getDocument().addDocumentListener(AreaListener);
rightDoc.getDocument().addDocumentListener(AreaListener);
}
DocumentListener listener = new DocumentListener()
public class AreaListener implements DocumentListener
{
//DocumentListener listener = new DocumentListener()
@Override
public void changedUpdate(DocumentEvent e)
{
convertInput();
}
@Override
public void insertUpdate(DocumentEvent e)
{
convertInput();
}
@Override
public void removeUpdate(DocumentEvent e)
{
convertInput();
}
private void convertInput(DocumentEvent e)
{
boolean arabicEntered = false;
boolean romanEntered = false;
for (char ch : userInputtedText.toCharArray())
{
if(Character.isLetter(ch))
{
romanEntered = true;
}
if(Character.isDigit(ch))
{
arabicEntered = true;
}
}
if(romanEntered = true)
{
if(ConversionLogic_Hard.getCheckFail() == false)
{
ConversionLogic_Hard.ConvertFromRomanToArabic(userInputtedText); //converts String of RomanNumerals to an arabic int
String arabicNumberAsString = ConversionLogic_Hard.getConvertedRomanNumeral(); //converts number from int to string
}
}
if(arabicEntered == true)
{
if(ConversionLogic_Hard.getCheckFail() == false)
{
ConversionLogic_Hard.ConvertFromArabicToRoman(userInputtedText); //converts String arabicNumberal to String roman numberal
String romanNumberalAsString = ConversionLogic_Hard.getConvertedRomanNumeral(); //gets romanNumberal as String
}
}
}//end convertInput
}//end AreaListener
//creates a flag to test the state of the TextArea
public class MirrorDocument extends PlainDocument
{
private boolean ignoreUpdatedText;
public void setIgnoreUpdates(boolean ignoreUpdatesText)
{
this.ignoreUpdatedText = ignoreUpdatesText;
}
public boolean isIgnoreUpdates()
{
return ignoreUpdatedText;
}
}
//when an event occurs checks the ignoreUpdatedText flag of the document to check if it is false.
//then sets the flag in the checkdocument to true to prevent the document listener from processing any new events.
//then updates the checkdocument.
public static class DocumentHandler implements DocumentListener
{
private MirrorDocument checkDocument;
private boolean ignoreUpdatedText = false;
private JTextArea leftdoc, rightdoc;
boolean arabicEntered = false;
boolean romanEntered = false;
public DocumentHandler(MirrorDocument checkDocument)
{
this.checkDocument = checkDocument;
}
@Override
public void removeUpdate(DocumentEvent e)
{
Document doc = e.getDocument();
if (doc instanceof MirrorDocument)
{
MirrorDocument mirrordoc = (MirrorDocument) doc;
if (!mirrordoc.isIgnoreUpdates())
{
try
{
checkDocument.setIgnoreUpdates(true);
checkDocument.remove(e.getOffset(), e.getLength());
}
catch (BadLocationException exc)
{
exc.printStackTrace();
}
finally
{
checkDocument.setIgnoreUpdates(false);
}
}
}
}//End removeUpdate
@Override
public void changedUpdate(DocumentEvent e)
{
//NOT USED
}
@Override
public void insertUpdate(DocumentEvent e)
{
Document doc = e.getDocument();
if (doc instanceof MirrorDocument)
{
MirrorDocument mirrordoc = (MirrorDocument) doc;
if( !mirrordoc.isIgnoreUpdates())
{
try
{
String textInput = e.getDocument().getText(e.getOffset(), e.getLength());
checkDocument.setIgnoreUpdates(true);
checkDocument.insertString(e.getOffset(), textInput, null);
}
catch(BadLocationException exc)
{
exc.printStackTrace();
}
finally
{
checkDocument.setIgnoreUpdates(false);
}
}
}
}//End insertUpdate
}
}//class
You can use a DocumentFilter to listen for changes.
When you create the DocumentFilter you can specify the text field to be updated with the converted text.
Using this approach you can then remove the DocumentFilter from the text field before you set its text so you avoid the recursion of two text fields trying to update one another.
The filter might look something like:
import javax.swing.*;
import javax.swing.text.*;
import java.awt.Toolkit;
public class ConversionFilter extends DocumentFilter
{
private boolean arabic;
private JTextField converted;
public ConversionFilter(boolean arabic, JTextField converted)
{
this.arabic = arabic;
this.converted = converted;
}
@Override
public void insertString(FilterBypass fb, int offs, String str, AttributeSet a)
throws BadLocationException
{
super.insertString(fb, offs, str, a);
convertInput(fb);
}
@Override
public void replace(final FilterBypass fb, final int offs, final int length, final String str, final AttributeSet a)
throws BadLocationException
{
super.replace(fb, offs, length, str, a);
convertInput(fb);
}
@Override
public void remove(DocumentFilter.FilterBypass fb, int offset, int length)
throws BadLocationException
{
super.remove(fb, offset, length);
convertInput(fb);
}
private void convertInput(DocumentFilter.FilterBypass fb)
{
// Remove the DocumentFilter from the text field to be converted
AbstractDocument document = (AbstractDocument)converted.getDocument();
DocumentFilter df = document.getDocumentFilter();
document.setDocumentFilter( null );
// Do the conversion and update the text field
String text = fb.getDocument().getText();
String convertedText = arabic ? convertToRoman(text) : convertToArabic(text);
converted.setText( convertedText );
// Restore the DocumentFilter on the converted text field
document.setDocumentFilter( df );
}
}
Then to use the filter the code might be something like:
JTextField arabicTextField = new JTextField(...);
JTextField romanTextField = new JTextField(...);
AbstractDocument arabicDocument = (AbstractDocument)arabicTextField.getDocument();
arabicDocument.setDocumentFilter( new ConversonFilter(true, romanTextField) );
AbstractDocument romanDocument = (AbstractDocument)romanTextField.getDocument();
romanDocument.setDocumentFilter( new ConversonFilter(false, arabicTextField) );
I used a DocumentFilter instead of a DocumentListener to be notified of changes to the Document simply because of the getter/setter method for the DocumentFilter make is easy to remove and restore the filter.