code: private boolean isBreakBoundary(int index) {
          BreakIterator breakiterator = search_.breakIter();
  
          if (breakiterator == null) {
              breakiterator = search_.internalBreakIter_;
          }
  
          return (breakiterator != null && breakiterator.isBoundary(index));
      }
docs: /*
  Returns TRUE if index is on a break boundary. If the UStringSearch
  has an external break iterator, test using that, otherwise test
  using the internal character break iterator.