git.gumartinm.name Git - JavaForFun/blob

   1 package de.spring.webservices.rest.controller.adapters;
   2
   3 import java.util.concurrent.CompletableFuture;
   4
   5 import org.slf4j.Logger;
   6 import org.slf4j.LoggerFactory;
   7 import org.springframework.web.context.request.async.DeferredResult;
   8
   9 public class CompletableFutureAdapter {
  10         private static final Logger LOGGER = LoggerFactory.getLogger(CompletableFutureAdapter.class);
  11
  12         /**
  13          *
  14          * WHEN EXCEPTION IN setErrorResult, Spring WILL TRIGGER THE Spring Exception Handler AS YOU KNOW IT (I HOPE)
  15          * SO, YOU COULD HOOK UP THE HANDLER AND RETURN YOUR CUSTOM MESSAGESS (as usual)
  16          *
  17          */
  18
  19         // With no value, we depend on the Tomcat/Jboss/Jetty/etc timeout value for asynchronous requests.
  20         // Spring will answer after 60 secs with an empty response (by default) and HTTP 503 status (by default) when timeout.
  21         private static final long ASYNC_TIMEOUT = 60000;  /* milliseconds */
  22
  23
  24         @FunctionalInterface
  25         public interface DeferredCall<T> {
  26
  27                 public T doCall();
  28         }
  29
  30
  31         public static final <T> DeferredResult<T> callAdapter(DeferredCall<T> deferredCall) {
  32
  33         DeferredResult<T> deferredResult = new DeferredResult<>(ASYNC_TIMEOUT);
  34         CompletableFuture
  35                 .supplyAsync(deferredCall::doCall)
  36                 .thenAcceptAsync(deferredResult::setResult)
  37                 .exceptionally(exception -> {
  38
  39                         LOGGER.error("findById error: ", exception);
  40
  41                         deferredResult.setErrorResult(exception);
  42
  43                         return null;
  44                 });
  45
  46         return deferredResult;
  47         }
  48
  49 }