Hi all.

I have problems problems restricting length of Japanese input
in JTextField. I use the following Document for restricting
the input length:

import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

public class CheckLengthDocument extends PlainDocument {

    private int numberOfChars = 0;

    public CheckLengthDocument(int c) {
        this.numberOfChars = c;
    }

    public void insertString(int offset, String str, AttributeSet
    attributeSet)
            throws BadLocationException {

        int capacity = this.numberOfChars + 1 - getContent().length();
        if (capacity >= str.length()) {
            super.insertString(offset, str, attributeSet);
        } else {
            super.insertString(offset, str.substring(0, capacity),
               attributeSet);
        }
    }
}

This document works fine with normal characters, but when entering
Japanese characters I can still enter characters when the maximum
length is reached and the newly entered characters overwrite the
previously entered characters. Of course this is not what I want.

How can I make this work correctly?

I am using JDK 1.3.1 on Windows2k/WindowsME. Switching to JDK
1.4/1.5 is not an option at the moment.

Christian