git.gumartinm.name Git - JavaForFun/blob

   1 package de.spring.webservices.rest.controller;
   2
   3 import java.util.Map;
   4 import java.util.concurrent.CompletableFuture;
   5
   6 import javax.inject.Inject;
   7
   8 import org.slf4j.Logger;
   9 import org.slf4j.LoggerFactory;
  10 import org.springframework.data.domain.Page;
  11 import org.springframework.data.domain.PageRequest;
  12 import org.springframework.http.HttpHeaders;
  13 import org.springframework.http.HttpStatus;
  14 import org.springframework.http.MediaType;
  15 import org.springframework.http.ResponseEntity;
  16 import org.springframework.web.bind.annotation.PathVariable;
  17 import org.springframework.web.bind.annotation.RequestBody;
  18 import org.springframework.web.bind.annotation.RequestHeader;
  19 import org.springframework.web.bind.annotation.RequestMapping;
  20 import org.springframework.web.bind.annotation.RequestMethod;
  21 import org.springframework.web.bind.annotation.RequestParam;
  22 import org.springframework.web.bind.annotation.ResponseStatus;
  23 import org.springframework.web.bind.annotation.RestController;
  24 import org.springframework.web.context.request.async.DeferredResult;
  25
  26 import de.spring.webservices.domain.Car;
  27 import de.spring.webservices.rest.business.service.AwesomeBusinessLogic;
  28
  29 @RestController
  30 @RequestMapping("/api/deferrable/cars/")
  31 public class DeferrableCarController {
  32         private static final Logger LOGGER = LoggerFactory.getLogger(DeferrableCarController.class);
  33         private static final int PAGE = 2;
  34         private static final int PAGE_SIZE = 10;
  35
  36         // With no value, we depend on the Tomcat/Jboss/Jetty/etc timeout value for asynchronous requests.
  37         // Spring will answer after 60 secs with an empty response (by default) and HTTP 503 status (by default) when timeout.
  38         private static final long ASYNC_TIMEOUT = 60000;  /* milliseconds */
  39
  40         /**
  41          *
  42          * WHEN EXCEPTION IN setErrorResult, Spring WILL TRIGGER THE Spring Exception Handler AS YOU KNOW IT (I HOPE)
  43          * SO, YOU COULD HOOK UP THE HANDLER AND RETURN YOUR CUSTOM MESSAGESS (as usual)
  44          *
  45          */
  46
  47         private final AwesomeBusinessLogic awesomeBusinessLogic;
  48
  49         @Inject
  50     public DeferrableCarController(AwesomeBusinessLogic awesomeBusinessLogic) {
  51                 this.awesomeBusinessLogic = awesomeBusinessLogic;
  52         }
  53
  54         @RequestMapping(produces = { MediaType.APPLICATION_JSON_UTF8_VALUE }, method = RequestMethod.GET)
  55     @ResponseStatus(HttpStatus.OK)
  56     public DeferredResult<Page<Car>> cars() {
  57
  58         // THIS CODE (I GUESS) SHOULD BE LOCATED IN Service layer. Anyhow this is just an example.
  59         DeferredResult<Page<Car>> deferredResult = new DeferredResult<>(ASYNC_TIMEOUT);
  60         CompletableFuture
  61                 .supplyAsync(() -> awesomeBusinessLogic.findAll(new PageRequest(PAGE, PAGE_SIZE)))
  62                 .thenAcceptAsync(car -> deferredResult.setResult(car))
  63                 .exceptionally(exception -> {
  64                         LOGGER.error("findAll error: ", exception);
  65
  66                         // DO NOT FORGET THE EXCEPTIONS.
  67                         // It will trigger the Spring Exception Handler as you know it :)
  68                         deferredResult.setErrorResult(exception);
  69
  70                         return null;
  71                 });
  72
  73         return deferredResult;
  74     }
  75
  76     @RequestMapping(value = "{id}", produces = MediaType.APPLICATION_JSON_UTF8_VALUE, method = RequestMethod.GET)
  77     @ResponseStatus(HttpStatus.OK)
  78     public DeferredResult<Car> car(@RequestHeader(value = "MY_HEADER", required = false) String specialHeader,
  79                         @PathVariable("id") long id,
  80                         @RequestParam Map<String, String> params,
  81                         @RequestParam(value = "wheel", required = false) String[] wheelParams) {
  82
  83         if (specialHeader != null) {
  84                 LOGGER.info("SPECIAL HEADER: " + specialHeader);
  85         }
  86
  87         if (params.get("mirror") != null) {
  88                 LOGGER.info("MIRROR: " + params.get("mirror"));
  89         }
  90
  91         if (params.get("window") != null) {
  92                 LOGGER.info("WINDOW: " + params.get("window"));
  93         }
  94
  95         if (wheelParams != null) {
  96                 for(String wheel : wheelParams) {
  97                         LOGGER.info(wheel);
  98                 }
  99         }
 100
 101         // THIS CODE (I GUESS) SHOULD BE LOCATED IN Service layer. Anyhow this is just an example.
 102         DeferredResult<Car> deferredResult = new DeferredResult<>(ASYNC_TIMEOUT);
 103         CompletableFuture
 104                 .supplyAsync(() -> awesomeBusinessLogic.findById(id))
 105                 .thenAcceptAsync(car -> deferredResult.setResult(car))
 106                 .exceptionally(exception -> {
 107
 108                         LOGGER.error("findById error: ", exception);
 109
 110                         // DO NOT FORGET THE EXCEPTIONS.
 111                         // It will trigger the Spring Exception Handler as you know it :)
 112                         deferredResult.setErrorResult(exception);
 113
 114                         return null;
 115                 });
 116
 117         return deferredResult;
 118     }
 119
 120     @RequestMapping(consumes = MediaType.APPLICATION_JSON_UTF8_VALUE,
 121                 produces = MediaType.APPLICATION_JSON_UTF8_VALUE, method = RequestMethod.POST)
 122         @ResponseStatus(HttpStatus.CREATED)
 123     public DeferredResult<ResponseEntity<Car>> create(@RequestBody Car car) {
 124
 125         // THIS CODE (I GUESS) SHOULD BE LOCATED IN Service layer. Anyhow this is just an example.
 126         DeferredResult<ResponseEntity<Car>> deferredResult = new DeferredResult<>(ASYNC_TIMEOUT);
 127         CompletableFuture
 128                 .supplyAsync(() -> {
 129                         Car createdCar = awesomeBusinessLogic.create(car);
 130
 131                         HttpHeaders headers = new HttpHeaders();
 132                     headers.add(HttpHeaders.LOCATION, "/api/cars/" + createdCar.getId());
 133                     return new ResponseEntity<>(createdCar, headers, HttpStatus.CREATED);
 134                 })
 135                 .thenAcceptAsync(response -> deferredResult.setResult(response))
 136                 .exceptionally(exception -> {
 137
 138                         LOGGER.error("create error: ", exception);
 139
 140                         // DO NOT FORGET THE EXCEPTIONS.
 141                         // It will trigger the Spring Exception Handler as you know it :)
 142                         deferredResult.setErrorResult(exception);
 143
 144                         return null;
 145                 });
 146
 147                 return deferredResult;
 148     }
 149
 150 }