code: protected void append(Object object, int index) {
  		if (object == null)
  			return;
  		if (object instanceof String) {
  			append((String) object, index);
  		} else if (object instanceof StringConcatenation) {
  			StringConcatenation other = (StringConcatenation) object;
  			appendSegments(index, other.getSignificantContent(), other.lineDelimiter);
  		} else if (object instanceof StringConcatenationClient) {
  			StringConcatenationClient other = (StringConcatenationClient) object;
  			other.appendTo(new SimpleTarget(this, index));
  		} else {
  			final String text = getStringRepresentation(object);
  			if (text != null) {
  				append(text, index);
  			}
  		}
  	}
docs: /*
  Add the string representation of the given object to this sequence at the given index. Does nothing if the object
  is <code>null</code>.
  
  @param object
  the to-be-appended object.
  @param index
  the index in the list of segments.