private List<EventPair<?>> collectStatistics() {
    final List<EventPair<?>> data = new ArrayList<>(15);

    data.add(JavaExtractMethodCollector.PARAMETERS_COUNT_FIELD.with(myVariableData.getInputVariables().size()));

    final Map<PsiVariable, ParameterInfo> resultParams = getParameterInfos(getChosenParameters());
    final List<Pair<ParameterInfo, ParameterInfo>> parameterChanges = ContainerUtil.map(getChosenParameters(), (param) ->
      new Pair<>(resultParams.get(param.variable), myInitialParameterInfos.get(param.variable))
    );
    if (!resultParams.isEmpty()) {
      boolean renamed = ContainerUtil.exists(parameterChanges, (changePair) -> !changePair.first.myName.equals(changePair.second.myName));
      boolean typeChanged =
        ContainerUtil.exists(parameterChanges, (changePair) -> !changePair.first.myType.equals(changePair.second.myType));
      boolean removed = ContainerUtil.exists(parameterChanges, (changePair) -> !changePair.first.myIsEnabled);
      data.add(JavaExtractMethodCollector.PARAMETERS_TYPE_CHANGED_FIELD.with(typeChanged));
      data.add(JavaExtractMethodCollector.PARAMETERS_RENAMED_FIELD.with(renamed));
      data.add(JavaExtractMethodCollector.PARAMETERS_REMOVED_FIELD.with(removed));
    }
    if (resultParams.size() > 1) {
      boolean reordered = ContainerUtil.exists(parameterChanges, (changePair) -> changePair.first.myIndex != changePair.second.myIndex);
      data.add(JavaExtractMethodCollector.PARAMETERS_REORDERED_FIELD.with(reordered));
    }

    if (myVisibilityPanel != null) {
      data.add(JavaExtractMethodCollector.VISIBILITY_CHANGED_FIELD.with(!myDefaultVisibility));
    }
    if (isReturnVisible) {
      data.add(JavaExtractMethodCollector.RETURN_CHANGED_FIELD.with(getReturnType() != myReturnType));
    }
    if (myMakeStatic != null && myMakeStatic.isEnabled()) {
      data.add(JavaExtractMethodCollector.STATIC_FIELD.with(myMakeStatic.isSelected()));
      data.add(JavaExtractMethodCollector.STATIC_PASS_AVAILABLE_FIELD.with(myVariableData.isPassFields()));
    }
    if (myMakeVarargs != null) {
      data.add(JavaExtractMethodCollector.MAKE_VARARGS_FIELD.with(myMakeVarargs.isSelected()));
    }
    if (myFoldParameters != null && myFoldParameters.isVisible()) {
      data.add(JavaExtractMethodCollector.FOLDED_FIELD.with(myFoldParameters.isSelected()));
    }
    if (myCbChainedConstructor != null) {
      data.add(JavaExtractMethodCollector.CONSTRUCTOR_FIELD.with(myCbChainedConstructor.isSelected()));
    }
    if (myGenerateAnnotations != null) {
      data.add(JavaExtractMethodCollector.ANNOTATED_FIELD.with(myGenerateAnnotations.isSelected()));
    }
    if (hasPreviewButton()) {
      data.add(JavaExtractMethodCollector.PREVIEW_USED_FIELD.with(isPreviewUsages()));
    }
    data.add(JavaExtractMethodCollector.FINISHED_FIELD.with(isOK()));
    return data;
  }
private List<EventPair<?>> collectStatistics()