Map<Element, Element> map;

  CollectionBenchmarkSampleData elems;

  @Param({"0", "1", "100", "10000"})
  int elements;

  @BeforeExperiment
  public void prepareContents() throws Exception {
    mapsImpl = mapEnums.get(implName);
    elems = new CollectionBenchmarkSampleData(elements);
    contents = Maps.newHashMap();
    for (Element key : elems.getValuesInSet()) {
      contents.put(key, key);
    }