How to limit the size in a cell belonging to a JTable

Question

We are handeling a JTable control and we've just realized we aren't able to capture the focuslost event in this control. Hence, We want to know how we can advise the user when he has written more character than are allowed.

Answer 1

here jr. Look at this...
//Prior to J2SE 1.4, limiting the capacity of a text component involved overriding
//the insertString() method of the component's model. Here's an example:
    JTextComponent textComp = new JTextField();
    textComp.setDocument(new FixedSizePlainDocument(10));
    class FixedSizePlainDocument extends PlainDocument {
        int maxSize;
        public FixedSizePlainDocument(int limit) {
            maxSize = limit;
        public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
            if ((getLength() + str.length()) <= maxSize) {
                super.insertString(offs, str, a);
            } else {
                throw new BadLocationException("Insertion exceeds max size of document", offs);
//J2SE 1.4 allows the ability to filter all editing operations on a text component.
//Here's an example that uses the new filtering capability to limit the capacity of the text component:
    JTextComponent textComponent = new JTextField();
    AbstractDocument doc = (AbstractDocument)textComponent.getDocument();
    doc.setDocumentFilter(new FixedSizeFilter(10));
    class FixedSizeFilter extends DocumentFilter {
        int maxSize;
        // limit is the maximum number of characters allowed.
        public FixedSizeFilter(int limit) {
            maxSize = limit;
        // This method is called when characters are inserted into the document
        public void insertString(DocumentFilter.FilterBypass fb, int offset, String str,
                AttributeSet attr) throws BadLocationException {
            replace(fb, offset, 0, str, attr);
        // This method is called when characters in the document are replace with other characters
        public void replace(DocumentFilter.FilterBypass fb, int offset, int length,
                String str, AttributeSet attrs) throws BadLocationException {
            int newLength = fb.getDocument().getLength()-length+str.length();
            if (newLength <= maxSize) {
                fb.replace(offset, length, str, attrs);
            } else {
                throw new BadLocationException("New characters exceeds max size of document", offset);
    }