@Test
public void _09_결과모으기() {
// collect로 모으기
HashSet<String> result = words.stream().collect(HashSet::new, HashSet::add, HashSet::addAll);
// 통계 뽑기(합계, 평균, 최댓값, 최솟값등..)
IntSummaryStatistics summary =
words.stream().collect(Collectors.summarizingInt(String::length));
assertThat(summary.getCount(), is(9989L));
assertThat(summary.getAverage(), is(3.9401341475623184D));
assertThat(summary.getMax(), is(14));
}
private static void printStatistic(
GraalTruffleRuntime rt, String label, IntSummaryStatistics value) {
rt.log(
String.format(
" %-50s: count=%4d, sum=%8d, min=%8d, average=%12.2f, max=%8d ",
label,
value.getCount(),
value.getSum(),
value.getMin(),
value.getAverage(),
value.getMax()));
}
/** {@inheritDoc} */
@Override
public RequestAggregationValues aggregate(RequestCollector requests) {
IntSummaryStatistics stats =
requests
.getReqTimestamps()
.stream()
.collect(
Collectors.groupingBy(
timestamp -> DateUtils.round(new Date(timestamp), timestampAggregation),
Collectors.counting()))
.values()
.stream()
.mapToInt(p -> toInt(p))
.summaryStatistics();
return new RequestAggregationValuesImpl(
stats.getMin(), stats.getMax(), stats.getAverage(), stats.getSum(), stats.getCount());
}