DocumentFilter in java and ctrl+v is not working

Question

When I'm trying to use of this DocumentFilter the ctrl+v and ctrl+c is not working.

public class stringLengthTrim extends DocumentFilter {

private int limit;

public stringLengthTrim(int limit) {
    this.limit = limit;
}

@Override
public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr) throws BadLocationException {
    Document innerDoc = fb.getDocument();
    StringBuilder sb = new StringBuilder(innerDoc.getText(0, innerDoc.getLength()));
    sb.insert(offset, string);
    if (textOK(sb.toString())) {
        super.insertString(fb, offset, string, attr);
    }
}

@Override
public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
    Document innerDoc = fb.getDocument();
    StringBuilder sb = new StringBuilder(innerDoc.getText(0, innerDoc.getLength()));
    int start = offset;
    int end = offset + length;
    sb.replace(start, end, text);
    if (textOK(sb.toString())) {
        super.replace(fb, offset, length, text, attrs);
    }
}

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

private boolean textOK(String text) {
    if (text.length() <= limit) {
        return true;
    }
    return false;
}
}

what can i do ? i'm using this documentfilter just for control the length of input text.is another way to restrict the length of JTextarea or JTextfield?

how to set documentfilter to support ctrl+v and ctrl+c?

and this is usage:

PlainDocument cID = (PlainDocument) contentID.getDocument();
cID.setDocumentFilter(new stringLengthTrim(9));

the contentID is a JTextarea.