code: public boolean checkRegionMatches(String str, int strStartIndex, String search) {
          return str.regionMatches(!isSensitive, strStartIndex, search, 0, search.length());
      }
docs: Checks if one string contains another at a specific index using the case-sensitivity rule.
  <p>
  This method mimics parts of {@link String#regionMatches(boolean, int, String, int, int)}
  but takes case-sensitivity into account.
  
  @param str  the string to check, not null
  @param strStartIndex  the index to start at in str
  @param search  the start to search for, not null
  @return true if equal using the case rules
  @throws NullPointerException if either string is null