Best way to limit max number of characters per line in JEditorPane ?

Hi,

I need to write swing based editor using which allows the user to
write a plain text document, which has a fixed maximum column width.
The column width will be supplied by the model class later. I finally
managed to write one using a document filter, as shown below. My
question is this the best (or a reasonable) way to realize this or are
there better options / solutions / ideas ?

Any comments are welcome.

[code]
public class LMEditor extends JFrame {

    private int frameWidth = 600 ;
    private int frameHeight = 400 ;
    private JEditorPane motivationTxtEdt = null ;
                private static final int MAXCOLUMNS = 30 ;

    public LMEditor(){
        super() ;
        initialize() ;
    }

    public void initialize() {

        // Init frame
        setDefaultCloseOperation(EXIT_ON_CLOSE) ;
        this.setSize(frameWidth,frameHeight) ;

.... irrelevant code ...

        motivationTxtEdt = new JEditorPane() ;
        motivationTxtEdt.setBounds(20,120,400,300) ;
        motivationTxtEdt.setContentType("text/plain") ;
        Document motivationDoc = motivationTxtEdt.getDocument();
                    DocumentFilter motivationFilter = new
ColumnWidthDocumentFilter(MAXCOLUMNS,motivationTxtEdt);
                    ((AbstractDocument) motivationDoc).setDocumentFilter
(motivationFilter);
        LMEditorPanel.add(motivationTxtEdt) ;

         setVisible(true) ;

    }

    class ColumnWidthDocumentFilter extends DocumentFilter {

        int maxColumnWidth = 0 ;
        JEditorPane motivationEditorPane = null ;

        public ColumnWidthDocumentFilter(int maxColumnWidth, JEditorPane
motivationEditorPane) {

            this.maxColumnWidth = maxColumnWidth ;
            this.motivationEditorPane = motivationEditorPane ;

        }

        public void insertString(DocumentFilter.FilterBypass fb, int offset,
String string,
                AttributeSet attr) throws BadLocationException {
            super.insertString(fb, offset, string, attr);
        }

        public void remove(DocumentFilter.FilterBypass fb, int offset, int
length)
                throws BadLocationException {
            super.remove(fb, offset, length);
   }

        public void replace(DocumentFilter.FilterBypass fb, int offset, int
length, String text,
                AttributeSet attrs) throws BadLocationException {

            // Get the caret position
            int caretPosition = motivationEditorPane.getCaretPosition() ;
            // Get line and linestart of root Document
            Element root = fb.getDocument().getDefaultRootElement() ;
            int line = root.getElementIndex( caretPosition );
            int lineStart = root.getElement( line ).getStartOffset();

            if (((caretPosition - lineStart + 1) < this.maxColumnWidth) ||
(text == "\n")) {
                super.replace(fb, offset, length, text, attrs);
            }

          }

        }