package tim.prune.load; import javax.swing.text.AttributeSet; import javax.swing.text.BadLocationException; import javax.swing.text.PlainDocument; /** * Document class to restrict text input to single character * for selection of custom delimiter */ public class OneCharDocument extends PlainDocument { public void insertString(int offs, String str, AttributeSet a) throws BadLocationException { //This rejects the insertion if it would make //the contents too long. if ((getLength() + str.length()) <= 1) super.insertString(offs, str, a); } }