Concurrency>cat TimeBudget.java
import java.util.*;
import java.util.concurrent.*;
/**
* QuoteTask
* <p/>
* Requesting travel quotes under a time budget
*/
public class TimeBudget {
private static ExecutorService exec = Executors.newCachedThreadPool();
public static void main(String args[]) {
TimeBudget tb = new TimeBudget();
Set<TravelCompany> companies = new HashSet<>();
companies.add(travelInfo -> new TravelQuoteImpl(1000, "aaa"));
companies.add(travelInfo -> new TravelQuoteImpl(1048, "bbb"));
companies.add(travelInfo -> {Thread.sleep(2000);return new TravelQuoteImpl(2489, "ccc");});
companies.add(travelInfo -> new TravelQuoteImpl(876, "xyzcode"));
companies.add(travelInfo -> new TravelQuoteImpl(1209, "xyznetwork"));
try {
List<TravelQuote> quotes = tb.getRankedTravelQuotes(
() -> "07-03-2017,NYC,Boston",
companies,
Comparator.nullsFirst(Comparator.comparingInt(TravelQuote::getPrice)),
1, TimeUnit.SECONDS);
quotes.stream().filter(i -> i != null).map(TravelQuote::getQuote).forEach(System.out::println);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public List<TravelQuote> getRankedTravelQuotes(TravelInfo travelInfo, Set<TravelCompany> companies,
Comparator<TravelQuote> ranking, long time, TimeUnit unit)
throws InterruptedException {
List<QuoteTask> tasks = new ArrayList<QuoteTask>();
for (TravelCompany company : companies)
tasks.add(new QuoteTask(company, travelInfo));
List<Future<TravelQuote>> futures = exec.invokeAll(tasks, time, unit); //time out
List<TravelQuote> quotes =
new ArrayList<TravelQuote>(tasks.size());
Iterator<QuoteTask> taskIter = tasks.iterator();
for (Future<TravelQuote> f : futures) {
QuoteTask task = taskIter.next();
try {
quotes.add(f.get());
} catch (ExecutionException e) {
quotes.add(task.getFailureQuote(e.getCause()));
} catch (CancellationException e) {
quotes.add(task.getTimeoutQuote(e));
}
}
exec.shutdown();
exec.awaitTermination(10, TimeUnit.SECONDS);
Collections.sort(quotes, ranking);
return quotes;
}
}
class QuoteTask implements Callable<TravelQuote> {
private final TravelCompany company;
private final TravelInfo travelInfo;
public QuoteTask(TravelCompany company, TravelInfo travelInfo) {
this.company = company;
this.travelInfo = travelInfo;
}
TravelQuote getFailureQuote(Throwable t) {
return null;
}
TravelQuote getTimeoutQuote(CancellationException e) {
return null;
}
public TravelQuote call() throws Exception {
return company.solicitQuote(travelInfo);
}
}
interface TravelCompany {
TravelQuote solicitQuote(TravelInfo travelInfo) throws Exception;
}
class TravelQuoteImpl implements TravelQuote {
private int price = 0;
private String name;
TravelQuoteImpl(int price, String name) {
this.price = price;
this.name = name;
}
@Override
public String getQuote() {
return name + ":" + this.price;
}
@Override
public int getPrice() {
return price;
}
}
interface TravelQuote {
String getQuote();
int getPrice();
}
interface TravelInfo {
String getDateAndCities();
}
Concurrency>javac TimeBudget.java
Concurrency>date; java TimeBudget; date
Sat Jul 15 23:45:13 EDT 2017
xyzcode:876
aaa:1000
bbb:1048
xyznetwork:1209
Sat Jul 15 23:45:14 EDT 2017
Concurrency>
