class BloombergEQVanillaOptionChain {

  public BloombergEQVanillaOptionChain narrowByOptionType(final OptionType optionType) {
    // Simple O(n) filtering on optiontype
    List<ExternalId> result = new ArrayList<ExternalId>(Collections2.filter(_identifiers, new Predicate<ExternalId>() {
      public boolean apply(ExternalId identifier) {
        return new BloombergTickerParserEQVanillaOption(identifier).getOptionType().equals(optionType);
      }
    }));
    return new BloombergEQVanillaOptionChain(result);
  }

  public  BloombergEQVanillaOptionChain(Set<ExternalId> identifiers);
  public  BloombergEQVanillaOptionChain(List<ExternalId> identifiers);
  public  BloombergEQVanillaOptionChain(BloombergEQVanillaOptionChain original);

}