The goal is to send a HTTP GET request containing a list of string representing the enum values QuestionSubject, then use those parameters to select the questions of the right subject. I also added a custom converter to convert the received string to my enum. My problem is that "subjects" is always null when I debug inside the method.
This is my current REST endpoint:
#ResponseBody
#GetMapping(path = "question/getquestionsbysubjects")
public List<Question> loadQuestionsBySubjects(#RequestParam(required=false) QuestionSubject[] subjects) throws IOException, GeneralSecurityException {
if(subjects == null || subjects.length == 0){
return this.loadAllQuestions();
}
return questionRepository.findByQuestionSubjectIn(Arrays.asList(subjects));
}
I am able to get my questions when passing a single subject in a method with the following signature:
public List<Question> loadQuestionsBySubjects(#RequestParam(required=false) QuestionSubject subject)
So it does not appear to be an issue of converting the string to enum.
I tried sending multiple requests, but subjects is always null in the endpoint. Here's what I already tried using postman:
http://localhost:8080/question/getquestionsbysubjects?subjects=contacts,ko
http://localhost:8080/question/getquestionsbysubjects?subjects=["contacts", "ko"]
http://localhost:8080/question/getquestionsbysubjects?subjects=contacts&subjects=ko
Is there an issue I'm not aware of? Those seems to be working in what I found in other questions.
Here's the converter:
public class StringToQuestionSubjectConverter implements Converter<String, QuestionSubject> {
#Override
public QuestionSubject convert(String source) {
return QuestionSubject.valueOf(source.toUpperCase());
}
public Iterable<QuestionSubject> convertAll(String[] sources) {
ArrayList<QuestionSubject> list = new ArrayList<>();
for (String source : sources) {
list.add(this.convert(source));
}
return list;
}
}
Use a List directly:
#RequestParam(required=false) List<QuestionSubject> subjects
return questionRepository.findByQuestionSubjectIn(subjects);
Related
Does anyone know how I can mark an argument on ActionDescriptor.Parameters to behave in a similar way the [BindNever] is behaving?
I want to always exclude a specific argument from a specific type without keep decorating it on the Controller.
Essentially I would like to be able to add my injected to my functions somehow how similar to the way its done with CancellationToken
public class TestController : ControllerBase
{
[HttpGet(Name = "Get")]
public IActionResult Get([BindNever] IInjectedInterface injected)
{
//Injected can be used in this method
return Ok();
}
[HttpPost(Name = "Post")]
public IActionResult Post([BindNever] IInjectedInterface injected, FormModel formModel)
{
//Injected doesn't work here. There is an error that
/*System.InvalidOperationException: 'Action 'WebApplication3.Controllers.TestController.Post (WebApplication3)'
has more than one parameter that was specified or inferred as bound from request body. Only one parameter per action may be bound from body.
Inspect the following parameters, and use 'FromQueryAttribute' to specify bound from query, 'FromRouteAttribute' to specify bound from route,
and 'FromBodyAttribute' for parameters to be bound from body:
IInjectedInterface injected
FormModel formModel'
*/
return Ok();
}
}
public class ActionExecutionFilter : IAsyncActionFilter
{
public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
var injectedParam = context.ActionDescriptor.Parameters.SingleOrDefault(x => x.ParameterType == typeof(IInjectedInterface));
if (injectedParam != null)
{
context.ActionArguments[injectedParam.Name] = new Injected(99);
}
await next.Invoke();
}
private class Injected : IInjectedInterface
{
public Injected(int someData)
{
SomeData = someData;
}
public int SomeData { get; }
}
}
I was able to solve it. Apparently you need to add the following lines on your program.cs to avoid the model binder related errors.
options.ModelMetadataDetailsProviders.Add(
new ExcludeBindingMetadataProvider(typeof(IInjectedInterface)));
options.ModelMetadataDetailsProviders.Add(
new BindingSourceMetadataProvider(typeof(IInjectedInterface), BindingSource.Special));
I'm creating Spring Boot HATEOAS REST application. Code below shows how am I adding links, while GET request is send for specific Employee. I'm using RepresentationModelAssembler toModel function. There's also toCollectionModel function to Override, which I would like to use to convert List<Employees> to CollectionModel. -> This will be returned in /Employees/all endpoint.
And I dunno how to do that. So what I need is to pass List<Employees>, then all list elements needs to be processed by toModel functions, and then, like in toModel function I need possibility to add more links to it -> links to entire new collection (not individual items).
Looking forward for your answers!
#Component
public class EmployeeModelAssembler implements RepresentationModelAssembler<Employee, EntityModel<Employee>> {
#Override
public EntityModel<Employee> toModel(Employee employee) {
EntityModel<Employee> employeeEntityModel = EntityModel.of(employee);
Link selfLink = linkTo(methodOn(EmployeeController.class).getEmployeeById(employee.getId())).withSelfRel();
employeeEntityModel.add(selfLink);
return employeeEntityModel;
}
#Override
public CollectionModel<EntityModel<Employee>> toCollectionModel(Iterable<? extends Employee> entities) {
?? ?? ??
}
}
You can use something like this:
#GetMapping(produces = { "application/hal+json" })
public CollectionModel<Customer> getAllCustomers() {
List<Customer> allCustomers = customerService.allCustomers();
for (Customer customer : allCustomers) {
String customerId = customer.getCustomerId();
Link selfLink = linkTo(CustomerController.class).slash(customerId).withSelfRel();
customer.add(selfLink);
if (orderService.getAllOrdersForCustomer(customerId).size() > 0) {
Link ordersLink = linkTo(methodOn(CustomerController.class)
.getOrdersForCustomer(customerId)).withRel("allOrders");
customer.add(ordersLink);
}
}
Link link = linkTo(CustomerController.class).withSelfRel();
CollectionModel<Customer> result = CollectionModel.of(allCustomers, link);
return result;
}
Visit https://www.baeldung.com/spring-hateoas-tutorial#springhateoasinaction for detailed explanation
I'm using the gemfire-json-server module in SpringXD to populate a GemFire grid with json representation of “Order” objects. I understand the gemfire-json-server module saves data in Pdx form in GemFire. I’d like to read the contents of the GemFire grid into an “Order” object in my application. I get a ClassCastException that reads:
java.lang.ClassCastException: com.gemstone.gemfire.pdx.internal.PdxInstanceImpl cannot be cast to org.apache.geode.demo.cc.model.Order
I’m using the Spring Data GemFire libraries to read contents of the cluster. The code snippet to read the contents of the Grid follows:
public interface OrderRepository extends GemfireRepository<Order, String>{
Order findByTransactionId(String transactionId);
}
How can I use Spring Data GemFire to convert data read from the GemFire cluster into an Order object?
Note: The data was initially stored in GemFire using SpringXD's gemfire-json-server-module
Still waiting to hear back from the GemFire PDX engineering team, specifically on Region.get(key), but, interestingly enough if you annotate your application domain object with...
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type")
public class Order ... {
...
}
This works!
Under-the-hood I knew the GemFire JSONFormatter class (see here) used Jackson's API to un/marshal (de/serialize) JSON data to and from PDX.
However, the orderRepository.findOne(ID) and ordersRegion.get(key) still do not function as I would expect. See updated test class below for more details.
Will report back again when I have more information.
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = GemFireConfiguration.class)
#SuppressWarnings("unused")
public class JsonToPdxToObjectDataAccessIntegrationTest {
protected static final AtomicLong ID_SEQUENCE = new AtomicLong(0l);
private Order amazon;
private Order bestBuy;
private Order target;
private Order walmart;
#Autowired
private OrderRepository orderRepository;
#Resource(name = "Orders")
private com.gemstone.gemfire.cache.Region<Long, Object> orders;
protected Order createOrder(String name) {
return createOrder(ID_SEQUENCE.incrementAndGet(), name);
}
protected Order createOrder(Long id, String name) {
return new Order(id, name);
}
protected <T> T fromPdx(Object pdxInstance, Class<T> toType) {
try {
if (pdxInstance == null) {
return null;
}
else if (toType.isInstance(pdxInstance)) {
return toType.cast(pdxInstance);
}
else if (pdxInstance instanceof PdxInstance) {
return new ObjectMapper().readValue(JSONFormatter.toJSON(((PdxInstance) pdxInstance)), toType);
}
else {
throw new IllegalArgumentException(String.format("Expected object of type PdxInstance; but was (%1$s)",
pdxInstance.getClass().getName()));
}
}
catch (IOException e) {
throw new RuntimeException(String.format("Failed to convert PDX to object of type (%1$s)", toType), e);
}
}
protected void log(Object value) {
System.out.printf("Object of Type (%1$s) has Value (%2$s)", ObjectUtils.nullSafeClassName(value), value);
}
protected Order put(Order order) {
Object existingOrder = orders.putIfAbsent(order.getTransactionId(), toPdx(order));
return (existingOrder != null ? fromPdx(existingOrder, Order.class) : order);
}
protected PdxInstance toPdx(Object obj) {
try {
return JSONFormatter.fromJSON(new ObjectMapper().writeValueAsString(obj));
}
catch (JsonProcessingException e) {
throw new RuntimeException(String.format("Failed to convert object (%1$s) to JSON", obj), e);
}
}
#Before
public void setup() {
amazon = put(createOrder("Amazon Order"));
bestBuy = put(createOrder("BestBuy Order"));
target = put(createOrder("Target Order"));
walmart = put(createOrder("Wal-Mart Order"));
}
#Test
public void regionGet() {
assertThat((Order) orders.get(amazon.getTransactionId()), is(equalTo(amazon)));
}
#Test
public void repositoryFindOneMethod() {
log(orderRepository.findOne(target.getTransactionId()));
assertThat(orderRepository.findOne(target.getTransactionId()), is(equalTo(target)));
}
#Test
public void repositoryQueryMethod() {
assertThat(orderRepository.findByTransactionId(amazon.getTransactionId()), is(equalTo(amazon)));
assertThat(orderRepository.findByTransactionId(bestBuy.getTransactionId()), is(equalTo(bestBuy)));
assertThat(orderRepository.findByTransactionId(target.getTransactionId()), is(equalTo(target)));
assertThat(orderRepository.findByTransactionId(walmart.getTransactionId()), is(equalTo(walmart)));
}
#Region("Orders")
#JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type")
public static class Order implements PdxSerializable {
protected static final OrderPdxSerializer pdxSerializer = new OrderPdxSerializer();
#Id
private Long transactionId;
private String name;
public Order() {
}
public Order(Long transactionId) {
this.transactionId = transactionId;
}
public Order(Long transactionId, String name) {
this.transactionId = transactionId;
this.name = name;
}
public String getName() {
return name;
}
public void setName(final String name) {
this.name = name;
}
public Long getTransactionId() {
return transactionId;
}
public void setTransactionId(final Long transactionId) {
this.transactionId = transactionId;
}
#Override
public void fromData(PdxReader reader) {
Order order = (Order) pdxSerializer.fromData(Order.class, reader);
if (order != null) {
this.transactionId = order.getTransactionId();
this.name = order.getName();
}
}
#Override
public void toData(PdxWriter writer) {
pdxSerializer.toData(this, writer);
}
#Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof Order)) {
return false;
}
Order that = (Order) obj;
return ObjectUtils.nullSafeEquals(this.getTransactionId(), that.getTransactionId());
}
#Override
public int hashCode() {
int hashValue = 17;
hashValue = 37 * hashValue + ObjectUtils.nullSafeHashCode(getTransactionId());
return hashValue;
}
#Override
public String toString() {
return String.format("{ #type = %1$s, id = %2$d, name = %3$s }",
getClass().getName(), getTransactionId(), getName());
}
}
public static class OrderPdxSerializer implements PdxSerializer {
#Override
public Object fromData(Class<?> type, PdxReader in) {
if (Order.class.equals(type)) {
return new Order(in.readLong("transactionId"), in.readString("name"));
}
return null;
}
#Override
public boolean toData(Object obj, PdxWriter out) {
if (obj instanceof Order) {
Order order = (Order) obj;
out.writeLong("transactionId", order.getTransactionId());
out.writeString("name", order.getName());
return true;
}
return false;
}
}
public interface OrderRepository extends GemfireRepository<Order, Long> {
Order findByTransactionId(Long transactionId);
}
#Configuration
protected static class GemFireConfiguration {
#Bean
public Properties gemfireProperties() {
Properties gemfireProperties = new Properties();
gemfireProperties.setProperty("name", JsonToPdxToObjectDataAccessIntegrationTest.class.getSimpleName());
gemfireProperties.setProperty("mcast-port", "0");
gemfireProperties.setProperty("log-level", "warning");
return gemfireProperties;
}
#Bean
public CacheFactoryBean gemfireCache(Properties gemfireProperties) {
CacheFactoryBean cacheFactoryBean = new CacheFactoryBean();
cacheFactoryBean.setProperties(gemfireProperties);
//cacheFactoryBean.setPdxSerializer(new MappingPdxSerializer());
cacheFactoryBean.setPdxSerializer(new OrderPdxSerializer());
cacheFactoryBean.setPdxReadSerialized(false);
return cacheFactoryBean;
}
#Bean(name = "Orders")
public PartitionedRegionFactoryBean ordersRegion(Cache gemfireCache) {
PartitionedRegionFactoryBean regionFactoryBean = new PartitionedRegionFactoryBean();
regionFactoryBean.setCache(gemfireCache);
regionFactoryBean.setName("Orders");
regionFactoryBean.setPersistent(false);
return regionFactoryBean;
}
#Bean
public GemfireRepositoryFactoryBean orderRepository() {
GemfireRepositoryFactoryBean<OrderRepository, Order, Long> repositoryFactoryBean =
new GemfireRepositoryFactoryBean<>();
repositoryFactoryBean.setRepositoryInterface(OrderRepository.class);
return repositoryFactoryBean;
}
}
}
So, as you are aware, GemFire (and by extension, Apache Geode) stores JSON in PDX format (as a PdxInstance). This is so GemFire can interoperate with many different language-based clients (native C++/C#, web-oriented (JavaScript, Pyhton, Ruby, etc) using the Developer REST API, in addition to Java) and also to be able to use OQL to query the JSON data.
After a bit of experimentation, I am surprised GemFire is not behaving as I would expect. I created an example, self-contained test class (i.e. no Spring XD, of course) that simulates your use case... essentially storing JSON data in GemFire as PDX and then attempting to read the data back out as the Order application domain object type using the Repository abstraction, logical enough.
Given the use of the Repository abstraction and implementation from Spring Data GemFire, the infrastructure will attempt to access the application domain object based on the Repository generic type parameter (in this case "Order" from the "OrderRepository" definition).
However, the data is stored in PDX, so now what?
No matter, Spring Data GemFire provides the MappingPdxSerializer class to convert PDX instances back to application domain objects using the same "mapping meta-data" that the Repository infrastructure uses. Cool, so I plug that in...
#Bean
public CacheFactoryBean gemfireCache(Properties gemfireProperties) {
CacheFactoryBean cacheFactoryBean = new CacheFactoryBean();
cacheFactoryBean.setProperties(gemfireProperties);
cacheFactoryBean.setPdxSerializer(new MappingPdxSerializer());
cacheFactoryBean.setPdxReadSerialized(false);
return cacheFactoryBean;
}
You will also notice, I set the PDX 'read-serialized' property (cacheFactoryBean.setPdxReadSerialized(false);) to false in order to ensure data access operations return the domain object and not the PDX instance.
However, this had no affect on the query method. In fact, it had no affect on the following operations either...
orderRepository.findOne(amazonOrder.getTransactionId());
ordersRegion.get(amazonOrder.getTransactionId());
Both calls returned a PdxInstance. Note, the implementation of OrderRepository.findOne(..) is based on SimpleGemfireRepository.findOne(key), which uses GemfireTemplate.get(key), which just performs Region.get(key), and so is effectively the same as (ordersRegion.get(amazonOrder.getTransactionId();). The outcome should not be, especially with Region.get() and read-serialized set to false.
With the OQL query (SELECT * FROM /Orders WHERE transactionId = $1) generated from the findByTransactionId(String id), the Repository infrastructure has a bit less control over what the GemFire query engine will return based on what the caller (OrderRepository) expects (based on the generic type parameter), so running OQL statements could potentially behave differently than direct Region access using get.
Next, I went onto try modifying the Order type to implement PdxSerializable, to handle the conversion during data access operations (direct Region access with get, OQL, or otherwise). This had no affect.
So, I tried to implement a custom PdxSerializer for Order objects. This had no affect either.
The only thing I can conclude at this point is something is getting lost in translation between Order -> JSON -> PDX and then from PDX -> Order. Seemingly, GemFire needs additional type meta-data required by PDX (something like #JsonTypeInfo(use = JsonTypeInfo.Id.CLASS, include = JsonTypeInfo.As.PROPERTY, property = "#type") in the JSON data that PDXFormatter recognizes, though I am not certain it does.
Note, in my test class, I used Jackson's ObjectMapper to serialize the Order to JSON and then GemFire's JSONFormatter to serialize the JSON to PDX, which I suspect Spring XD is doing similarly under-the-hood. In fact, Spring XD uses Spring Data GemFire and is most likely using the JSON Region Auto Proxy support. That is exactly what SDG's JSONRegionAdvice object does (see here).
Anyway, I have an inquiry out to the rest of the GemFire engineering team. There are also things that could be done in Spring Data GemFire to ensure the PDX data is converted, such as making use of the MappingPdxSerializer directly to convert the data automatically on behalf of the caller if the data is indeed of type PdxInstance. Similar to how JSON Region Auto Proxying works, you could write AOP interceptor for the Orders Region to automagicaly convert PDX to an Order.
Though, I don't think any of this should be necessary as GemFire should be doing the right thing in this case. Sorry I don't have a better answer right now. Let's see what I find out.
Cheers and stay tuned!
See subsequent post for test code.
I am working with Spring-websocket and I have the following problem:
I am trying to put a placeholder inside a #MessageMapping annotation in order to get the url from properties. It works with #RequestMapping but not with #MessageMapping.
If I use this placeholder, the URL is null. Any idea or suggestion?
Example:
#RequestMapping(value= "${myProperty}")
#MessageMapping("${myProperty}")
Rossen Stoyanchev added placeholder support for #MessageMapping and #SubscribeMapping methods.
See Jira issue: https://jira.spring.io/browse/SPR-13271
Spring allows you to use property placeholders in #RequestMapping, but not in #MessageMapping. This is 'cause the MessageHandler. So, we need to override the default MessageHandler to do this.
WebSocketAnnotationMethodMessageHandler does not support placeholders and you need add this support yourself.
For simplicity I just created another WebSocketAnnotationMethodMessageHandler class in my project at the same package of the original, org.springframework.web.socket.messaging, and override getMappingForMethod method from SimpAnnotationMethodMessageHandler with same content, changing only how SimpMessageMappingInfo is contructed using this with this methods (private in WebSocketAnnotationMethodMessageHandler):
private SimpMessageMappingInfo createMessageMappingCondition(final MessageMapping annotation) {
return new SimpMessageMappingInfo(SimpMessageTypeMessageCondition.MESSAGE, new DestinationPatternsMessageCondition(
this.resolveAnnotationValues(annotation.value()), this.getPathMatcher()));
}
private SimpMessageMappingInfo createSubscribeCondition(final SubscribeMapping annotation) {
final SimpMessageTypeMessageCondition messageTypeMessageCondition = SimpMessageTypeMessageCondition.SUBSCRIBE;
return new SimpMessageMappingInfo(messageTypeMessageCondition, new DestinationPatternsMessageCondition(
this.resolveAnnotationValues(annotation.value()), this.getPathMatcher()));
}
These methods now will resolve value considering properties (calling resolveAnnotationValues method), so we need use something like this:
private String[] resolveAnnotationValues(final String[] destinationNames) {
final int length = destinationNames.length;
final String[] result = new String[length];
for (int i = 0; i < length; i++) {
result[i] = this.resolveAnnotationValue(destinationNames[i]);
}
return result;
}
private String resolveAnnotationValue(final String name) {
if (!(this.getApplicationContext() instanceof ConfigurableApplicationContext)) {
return name;
}
final ConfigurableApplicationContext applicationContext = (ConfigurableApplicationContext) this.getApplicationContext();
final ConfigurableBeanFactory configurableBeanFactory = applicationContext.getBeanFactory();
final String placeholdersResolved = configurableBeanFactory.resolveEmbeddedValue(name);
final BeanExpressionResolver exprResolver = configurableBeanFactory.getBeanExpressionResolver();
if (exprResolver == null) {
return name;
}
final Object result = exprResolver.evaluate(placeholdersResolved, new BeanExpressionContext(configurableBeanFactory, null));
return result != null ? result.toString() : name;
}
You still need to define a PropertySourcesPlaceholderConfigurer bean in your configuration.
If you are using XML based configuration, include something like this:
<context:property-placeholder location="classpath:/META-INF/spring/url-mapping-config.properties" />
If you are using Java based configuration, you can try in this way:
#Configuration
#PropertySources(value = #PropertySource("classpath:/META-INF/spring/url-mapping-config.properties"))
public class URLMappingConfig {
#Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
Obs.: in this case, url-mapping-config.properties file are in a gradle/maven project in src\main\resources\META-INF\spring folder and content look like this:
myPropertyWS=urlvaluews
This is my sample controller:
#Controller
public class WebSocketController {
#SendTo("/topic/test")
#MessageMapping("${myPropertyWS}")
public String test() throws Exception {
Thread.sleep(4000); // simulated delay
return "OK";
}
}
With default MessageHandler startup log will print something like this:
INFO: Mapped "{[/${myPropertyWS}],messageType=[MESSAGE]}" onto public java.lang.String com.brunocesar.controller.WebSocketController.test() throws java.lang.Exception
And with our MessageHandler now print this:
INFO: Mapped "{[/urlvaluews],messageType=[MESSAGE]}" onto public java.lang.String com.brunocesar.controller.WebSocketController.test() throws java.lang.Exception
See in this gist the full WebSocketAnnotationMethodMessageHandler implementation.
EDIT: this solution resolves the problem for versions before 4.2 GA. For more information, see this jira.
Update :
Now I understood what you mean, but I think that is not possible(yet).
Documentation does not mention anything related to Path mapping URIs.
Old answer
Use
#MessageMapping("/handler/{myProperty}")
instead of
#MessageMapping("/handler/${myProperty}")
And use it like this:
#MessageMapping("/myHandler/{username}")
public void handleTextMessage(#DestinationVariable String username,Message message) {
//do something
}
#MessageMapping("/chat/{roomId}")
public Message handleMessages(#DestinationVariable("roomId") String roomId, #Payload Message message, Traveler traveler) throws Exception {
System.out.println("Message received for room: " + roomId);
System.out.println("User: " + traveler.toString());
// store message in database
message.setAuthor(traveler);
message.setChatRoomId(Integer.parseInt(roomId));
int id = MessageRepository.getInstance().save(message);
message.setId(id);
return message;
}
I have one class that extends DeferredResults and extends Runnable as shown below
public class EventDeferredObject<T> extends DeferredResult<Boolean> implements Runnable {
private Long customerId;
private String email;
#Override
public void run() {
RestTemplate restTemplate=new RestTemplate();
EmailMessageDTO emailMessageDTO=new EmailMessageDTO("dineshshe#gmail.com", "Hi There");
Boolean result=restTemplate.postForObject("http://localhost:9080/asycn/sendEmail", emailMessageDTO, Boolean.class);
this.setResult(result);
}
//Constructor and getter and setters
}
Now I have controller that return the object of the above class,whenever new request comes to controller we check if that request is present in HashMap(That stores unprocessed request at that instance).If not present then we are creating object of EventDeferredObject class can store that in HashMap and call start() method on it.If this type request is already present then we will return that from HashMap.On completion on request we will delete that request from HashMap.
#RequestMapping(value="/sendVerificationDetails")
public class SendVerificationDetailsController {
private ConcurrentMap<String , EventDeferredObject<Boolean>> requestMap=new ConcurrentHashMap<String , EventDeferredObject<Boolean>>();
#RequestMapping(value="/sendEmail",method=RequestMethod.POST)
public EventDeferredObject<Boolean> sendEmail(#RequestBody EmailDTO emailDTO)
{
EventDeferredObject<Boolean> eventDeferredObject = null;
System.out.println("Size:"+requestMap.size());
if(!requestMap.containsKey(emailDTO.getEmail()))
{
eventDeferredObject=new EventDeferredObject<Boolean>(emailDTO.getCustomerId(), emailDTO.getEmail());
requestMap.put(emailDTO.getEmail(), eventDeferredObject);
Thread t1=new Thread(eventDeferredObject);
t1.start();
}
else
{
eventDeferredObject=requestMap.get(emailDTO.getEmail());
}
eventDeferredObject.onCompletion(new Runnable() {
#Override
public void run() {
if(requestMap.containsKey(emailDTO.getEmail()))
{
requestMap.remove(emailDTO.getEmail());
}
}
});
return eventDeferredObject;
}
}
Now this code works fine if there no identical request comes to that stored in HashMap. If we give number of different request at same time code works fine.
Well, I do not know if I understood correctly, but I think you might have race conditions in the code, for example here:
if(!requestMap.containsKey(emailDTO.getEmail()))
{
eventDeferredObject=new EventDeferredObject<Boolean>(emailDTO.getCustomerId(), emailDTO.getEmail());
requestMap.put(emailDTO.getEmail(), eventDeferredObject);
Thread t1=new Thread(eventDeferredObject);
t1.start();
}
else
{
eventDeferredObject=requestMap.get(emailDTO.getEmail());
}
think of a scenario in which you have two requests with the same key emailDTO.getEmail().
Request 1 checks if there is a key in the map, does not find it and puts it inside.
Request 2 comes some time later, checks if there is a key in the map, finds it, and
goes to fetch it; however just before that, the thread started by request 1 finishes and another thread, started by onComplete event, removes the key from the map. At this point,
requestMap.get(emailDTO.getEmail())
will return null, and as a result you will have a NullPointerException.
Now, this does look like a rare scenario, so I do not know if this is the problem you see.
I would try to modify the code as follows (I did not run it myself, so I might have errors):
public class EventDeferredObject<T> extends DeferredResult<Boolean> implements Runnable {
private Long customerId;
private String email;
private ConcurrentMap ourConcurrentMap;
#Override
public void run() {
...
this.setResult(result);
ourConcurrentMap.remove(this.email);
}
//Constructor and getter and setters
}
so the DeferredResult implementation has the responsibility to remove itself from the concurrent map. Moreover I do not use the onComplete to set a callback thread, as it seems to me an unnecessary complication. To avoid the race conditions I talked about before, one needs to combine somehow the verification of the presence of an entry with its fetching into one atomic operation; this is done by the putIfAbsent method of ConcurrentMap. Therefore I change the controller into
#RequestMapping(value="/sendVerificationDetails")
public class SendVerificationDetailsController {
private ConcurrentMap<String , EventDeferredObject<Boolean>> requestMap=new ConcurrentHashMap<String , EventDeferredObject<Boolean>>();
#RequestMapping(value="/sendEmail",method=RequestMethod.POST)
public EventDeferredObject<Boolean> sendEmail(#RequestBody EmailDTO emailDTO)
{
EventDeferredObject<Boolean> eventDeferredObject = new EventDeferredObject<Boolean>(emailDTO.getCustomerId(), emailDTO.getEmail(), requestMap);
EventDeferredObject<Boolean> oldEventDeferredObject = requestMap.putIfAbsent(emailDTO.getEmail(), eventDeferredObject );
if(oldEventDeferredObject == null)
{
//if no value was present before
Thread t1=new Thread(eventDeferredObject);
t1.start();
return eventDeferredObject;
}
else
{
return oldEventDeferredObject;
}
}
}
if this does not solve the problem you have, I hope that at least it might give some idea.