(バージョン情報なし。おそらく SVN 版にしか存在しないでしょう)
Objects of this class can be obtained from IntlBreakIterator objects. While the break iterators provide a sequence of boundary positions when iterated, IntlPartsIterator objects provide, as a convenience, the text fragments comprehended between two successive boundaries.
The keys may represent the offset of the left boundary, right boundary, or they may just the sequence of non-negative integers. See IntlBreakIterator::getPartsIterator().