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package org.glassfish.jersey.examples.rx.agent;
import java.util.Arrays;
import java.util.List;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.container.AsyncResponse;
import javax.ws.rs.container.Suspended;
import javax.ws.rs.core.GenericType;
import org.glassfish.jersey.client.rx.guava.RxListenableFutureInvoker;
import org.glassfish.jersey.client.rx.guava.RxListenableFutureInvokerProvider;
import org.glassfish.jersey.examples.rx.domain.AgentResponse;
import org.glassfish.jersey.examples.rx.domain.Calculation;
import org.glassfish.jersey.examples.rx.domain.Destination;
import org.glassfish.jersey.examples.rx.domain.Forecast;
import org.glassfish.jersey.examples.rx.domain.Recommendation;
import org.glassfish.jersey.server.ManagedAsync;
import org.glassfish.jersey.server.Uri;
import com.google.common.collect.Lists;
import com.google.common.util.concurrent.AsyncFunction;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
/**
* Obtain information about visited (destination) and recommended (destination, forecast, price) places for "Guava" user. Uses
* Guava ListenableFuture and Jersey Client to obtain the data.
*
* @author Michal Gajdos
* @author Pavel Bucek (pavel.bucek at oracle.com)
*/
@Path("agent/listenable")
@Produces("application/json")
public class ListenableFutureAgentResource {
@Uri("remote/destination")
private WebTarget destination;
@Uri("remote/calculation/from/{from}/to/{to}")
private WebTarget calculation;
@Uri("remote/forecast/{destination}")
private WebTarget forecast;
@GET
@ManagedAsync
public void listenable(@Suspended final AsyncResponse async) {
final long time = System.nanoTime();
final AgentResponse response = new AgentResponse();
// Obtain and set visited and recommended places to create a response ...
final ListenableFuture<List<AgentResponse>> successful = Futures.successfulAsList(
Arrays.asList(visited(response), recommended(response)));
// ... and when we have them, return response to the client.
Futures.addCallback(successful, new FutureCallback<List<AgentResponse>>() {
@Override
public void onSuccess(final List<AgentResponse> result) {
response.setProcessingTime((System.nanoTime() - time) / 1000000);
async.resume(response);
}
@Override
public void onFailure(final Throwable t) {
async.resume(t);
}
});
}
private ListenableFuture<AgentResponse> visited(final AgentResponse response) {
destination.register(RxListenableFutureInvokerProvider.class);
// Get a list of visited destinations ...
final ListenableFuture<List<Destination>> visited = destination.path("visited").request()
// Identify the user.
.header("Rx-User", "Guava")
// Reactive invoker.
.rx(RxListenableFutureInvoker.class)
// Return a list of destinations.
.get(new GenericType<List<Destination>>() {
});
// ... and set them to the final response.
return Futures.transform(visited, (AsyncFunction<List<Destination>, AgentResponse>) destinations -> {
response.setVisited(destinations);
return Futures.immediateFuture(response);
});
}
private ListenableFuture<AgentResponse> recommended(final AgentResponse response) {
destination.register(RxListenableFutureInvokerProvider.class);
// Get a list of recommended destinations ...
final ListenableFuture<List<Destination>> destinations = destination.path("recommended")
.request()
// Identify the user.
.header("Rx-User", "Guava")
// Reactive invoker.
.rx(RxListenableFutureInvoker.class)
// Return a list of destinations.
.get(new GenericType<List<Destination>>() {
});
// ... transform them to Recommendation instances ...
final ListenableFuture<List<Recommendation>> recommendations = Futures.transform(
destinations,
(AsyncFunction<List<Destination>, List<Recommendation>>) destinationList -> {
// Create new array list to avoid multiple remote calls.
final List<Recommendation> recommendationList = Lists.newArrayList(Lists.transform(
destinationList,
destination -> new Recommendation(destination.getDestination(), null, 0)));
return Futures.immediateFuture(recommendationList);
});
// ... add forecasts and calculations ...
final ListenableFuture<List<List<Recommendation>>> filledRecommendations = Futures
.successfulAsList(Arrays.asList(
// Add Forecasts to Recommendations.
forecasts(recommendations),
// Add Forecasts to Recommendations.
calculations(recommendations)));
// ... and transform the list into agent response with filled recommendations.
return Futures
.transform(filledRecommendations, (AsyncFunction<List<List<Recommendation>>, AgentResponse>) input -> {
response.setRecommended(input.get(0));
return Futures.immediateFuture(response);
});
}
private ListenableFuture<List<Recommendation>> forecasts(final ListenableFuture<List<Recommendation>> recommendations) {
forecast.register(RxListenableFutureInvokerProvider.class);
// Fill the list with weather forecast.
return Futures.transform(recommendations, (AsyncFunction<List<Recommendation>, List<Recommendation>>) list ->
// For each recommendation ...
Futures.successfulAsList(Lists.transform(list, recommendation -> Futures.transform(
// ... get the weather forecast ...
forecast.resolveTemplate("destination", recommendation.getDestination()).request()
.rx(RxListenableFutureInvoker.class)
.get(Forecast.class),
// ... and set it to the recommendation.
(AsyncFunction<Forecast, Recommendation>) forecast -> {
recommendation.setForecast(forecast.getForecast());
return Futures.immediateFuture(recommendation);
}))));
}
private ListenableFuture<List<Recommendation>> calculations(final ListenableFuture<List<Recommendation>> recommendations) {
calculation.register(RxListenableFutureInvokerProvider.class);
// Fill the list with price calculations.
return Futures.transform(recommendations, (AsyncFunction<List<Recommendation>, List<Recommendation>>) list ->
// For each recommendation ...
Futures.successfulAsList(Lists.transform(list, recommendation -> Futures.transform(
// ... get the price calculation ...
calculation.resolveTemplate("from", "Moon")
.resolveTemplate("to", recommendation.getDestination())
.request().rx(RxListenableFutureInvoker.class).get(Calculation.class),
// ... and set it to the recommendation.
(AsyncFunction<Calculation, Recommendation>) calculation -> {
recommendation.setPrice(calculation.getPrice());
return Futures.immediateFuture(recommendation);
})))
);
}
}