public void addAttribute (Attribute attribute, Object value, int beginIndex, int endIndex)

Adds an attribute to a subrange of the string.

Parameters:
attribute    the attribute key
value    The value of the attribute. May be null.
beginIndex    Index of the first character of the range.
endIndex    Index of the character following the last character of the range.

Exceptions:
NullPointerException    if attribute is null.
IllegalArgumentException    if beginIndex is less then 0, endIndex is greater than the length of the string, or beginIndex and endIndex together don't define a non-empty subrange of the string.