public static void main(String[] args) {
// how many sales?
long saleCount = saleStream().count();
System.out.println("Count of sales: " + saleCount);
// any sales over $100?
Supplier<DoubleStream> totalStream = () -> saleStream().mapToDouble(Sale::total);
boolean bigSaleDay = totalStream.get().anyMatch(total -> total > 100.00);
System.out.println("Big sale day? " + bigSaleDay);
// maximum sale amount?
DoubleSummaryStatistics stats = totalStream.get().summaryStatistics();
System.out.println("Max sale amount: " + stats.getMax());
System.out.println("Stats on total: " + stats);
// how many items were sold today?
Supplier<Stream<Item>> itemStream = () -> saleStream().flatMap(sale -> sale.items.stream());
long itemCount = itemStream.get().count();
System.out.println("Count of items: " + itemCount);
// which different items were sold today?
String uniqueItems =
itemStream.get().map(item -> item.identity).distinct().collect(Collectors.joining(" & "));
System.out.println("Distinct items: " + uniqueItems);
// summarize sales by store
ConcurrentMap<String, DoubleSummaryStatistics> summary =
saleStream()
.parallel()
.collect(
Collectors.groupingByConcurrent(
sale -> Thread.currentThread().getName(),
Collectors.summarizingDouble(Sale::total)));
System.out.println("Summary by thread: " + summary);
summary
.keySet()
.stream()
.sorted()
.forEach(store -> System.out.println(store + " stats: " + summary.get(store)));
}
/**
* Get the top n external Services of the given services.
*
* @param statistics
* @param externalServices
* @param timeRange
* @param limit
* @return
*/
public static List<ExternalServiceVo> topByAvgResponseTime(
Iterable<ExternalServiceStatistic> statistics,
Iterable<ExternalService> externalServices,
TimeRange timeRange,
Integer limit) {
Map<Long, ExternalService> rpcTransactionMap = new HashMap<>();
StreamSupport.stream(externalServices.spliterator(), false)
.forEach(transaction -> rpcTransactionMap.put(transaction.getId(), transaction));
Map<TransactionGroup, List<ExternalServiceStatistic>> groups =
StreamSupport.stream(statistics.spliterator(), false)
.collect(
Collectors.groupingBy(
new Function<ExternalServiceStatistic, TransactionGroup>() {
@Override
public TransactionGroup apply(ExternalServiceStatistic statistic) {
Long transactionId = statistic.getExternalServiceId();
ExternalService webTransaction = rpcTransactionMap.get(transactionId);
TransactionGroup group = new TransactionGroup();
group.setAppId(webTransaction.getAppId());
group.setDisplayName(webTransaction.getUrl());
return group;
}
}));
List<ExternalServiceVo> result = new ArrayList<>();
groups.forEach(
(group, webTransactionStatistics) -> {
DoubleSummaryStatistics responseSummaryStatistics =
webTransactionStatistics
.stream()
.filter(statistic -> statistic.getSumResponseTime() != null)
.mapToDouble(ExternalServiceStatistic::getSumResponseTime)
.summaryStatistics();
DoubleSummaryStatistics maxSummaryStatistics =
webTransactionStatistics
.stream()
.filter(statistic -> statistic.getMaxResponseTime() != null)
.mapToDouble(ExternalServiceStatistic::getMaxResponseTime)
.summaryStatistics();
DoubleSummaryStatistics minSummaryStatistics =
webTransactionStatistics
.stream()
.filter(statistic -> statistic.getMinResponseTime() != null)
.mapToDouble(ExternalServiceStatistic::getMinResponseTime)
.summaryStatistics();
LongSummaryStatistics pvSummaryStatistics =
webTransactionStatistics
.stream()
.filter(statistic -> statistic.getPv() != null)
.mapToLong(ExternalServiceStatistic::getPv)
.summaryStatistics();
ExternalServiceVo transaction = new ExternalServiceVo();
transaction.setAppId(group.getAppId());
transaction.setDestination(group.getDisplayName());
transaction.setPv(pvSummaryStatistics.getSum());
transaction.setCpm(
format(
calculateRate(
pvSummaryStatistics.getSum(), timeRange.getDuration(ChronoUnit.MINUTES))));
transaction.setMaxResponseTime(format(maxSummaryStatistics.getMax()));
transaction.setMinResponseTime(format(minSummaryStatistics.getMin()));
transaction.setResponseTime(
format(
calculateRate(responseSummaryStatistics.getSum(), pvSummaryStatistics.getSum())));
result.add(transaction);
});
return result
.stream()
.sorted(Comparator.comparing(ExternalServiceVo::getResponseTime))
.limit(limit)
.collect(Collectors.toList());
}