/**
  * Format the faulty source code line and point to the error.
  *
  * @param d The diagnostic for which the error line should be printed
  */
 protected String formatSourceLine(JCDiagnostic d, int nSpaces) {
   StringBuilder buf = new StringBuilder();
   DiagnosticSource source = d.getDiagnosticSource();
   int pos = d.getIntPosition();
   if (d.getIntPosition() == Position.NOPOS) throw new AssertionError();
   String line = (source == null ? null : source.getLine(pos));
   if (line == null) return "";
   buf.append(indent(line, nSpaces));
   int col = source.getColumnNumber(pos, false);
   if (config.isCaretEnabled()) {
     buf.append("\n");
     for (int i = 0; i < col - 1; i++) {
       buf.append((line.charAt(i) == '\t') ? "\t" : " ");
     }
     buf.append(indent("^", nSpaces));
   }
   return buf.toString();
 }
 // where
 private long getPosition(JCDiagnostic d, PositionKind pk) {
   switch (pk) {
     case START:
       return d.getIntStartPosition();
     case END:
       return d.getIntEndPosition();
     case LINE:
       return d.getLineNumber();
     case COLUMN:
       return d.getColumnNumber();
     case OFFSET:
       return d.getIntPosition();
     default:
       throw new AssertionError("Unknown diagnostic position: " + pk);
   }
 }
 public boolean displaySource(JCDiagnostic d) {
   return config.getVisible().contains(DiagnosticPart.SOURCE)
       && d.getType() != FRAGMENT
       && d.getIntPosition() != Position.NOPOS;
 }