When to use DeferredResult?

When to use DeferredResult?

DeferredResult<> is used to answer to a petition without blocking the Tomcat HTTP thread used to answer. Usually is going to be the return value for a ResponseBody annotated method.

How does DeferredResult work?

DeferredResult, available from Spring 3.2 onwards, assists in offloading a long-running computation from an http-worker thread to a separate thread. Although the other thread will take some resources for computation, the worker threads are not blocked in the meantime and can handle incoming client requests.

What is Callable in Spring?

Callable is a Java interface that is an useful methodology for control multi-threading returns on concurrency development. The tutorial will guide you to build a concurrency program with ThreadPoolTaskExecutor of Spring Framework and Callable interface.

Is Spring MVC asynchronous?

Spring 3.0 introduced the @Async annotation. @Async’s goal is to allow the application to run heavy-load jobs on a separate thread. Thus, since Spring 3.2, @Async can be used in classes annotated as @Controller or @RestController. …

What is the difference between future and CompletableFuture?

CompletableFuture is used for asynchronous programming in Java. A Future is used as a reference to the result of an asynchronous computation. It provides an isDone() method to check whether the computation is done or not, and a get() method to retrieve the result of the computation when it is done.

How do you make a REST service asynchronous?

To enable async configuration in spring, follow these steps:

1. Create async thread pool. AsyncConfiguration.java. @Configuration.
2. @Async controller methods. Methods which shall run asynchronously, annotate them with @Async annotation and method return type should return.
3. Combine async method results. Inside REST Controller.

What is SimpleAsyncTaskExecutor?

public class SimpleAsyncTaskExecutor extends CustomizableThreadCreator implements AsyncListenableTaskExecutor, Serializable. TaskExecutor implementation that fires up a new Thread for each task, executing it asynchronously. Supports limiting concurrent threads through the “concurrencyLimit” bean property.

What is non blocking REST API?

The term “non-blocking” really means the same thing whether it is happening on the server side or the client side. As the article above points out, blocking means that the thread you make the call on stops processing until the call has finished.

What is difference between runnable and Callable?

Difference between Callable and Runnable are following: Callable has call() method but Runnable has run() method. Callable has call method which returns value but Runnable has run method which doesn’t return any value. call method can throw checked exception but run method can’t throw checked exception.

Can Callable return a value?

The purpose of the Callable interface is similar to Runnable, but its method returns a value of type T. Integer value = result. This method blocks the current thread to wait until the computation completes and returns the value.

What is DeferredResult?

DeferredResult provides an alternative to using a Callable for asynchronous request processing. While a Callable is executed concurrently on behalf of the application, with a DeferredResult the application can produce the result from a thread of its choice.

Is Java synchronous or asynchronous?

The main difference between synchronous and asynchronous calls in Java is that, in synchronous calls, the code execution waits for the event before continuing while asynchronous calls do not block the program from the code execution. It is executed after an event.

When to use deferredresult in spring 3.2?

DeferredResult, available from Spring 3.2 onwards, assists in offloading a long-running computation from an http-worker thread to a separate thread. Although the other thread will take some resources for computation, the worker threads are not blocked in the meantime and can handle incoming client requests.

How to use deferredresult for non-blocking rest?

Non-Blocking REST Using DeferredResult To avoid blocking, we’ll use callbacks-based programming model where instead of the actual result, we’ll return a DeferredResult to the servlet container. Request processing is done in a separate thread and once completed we invoke the setResult operation on the DeferredResult object.

When to invoke setresult on deferredresult object?

Request processing is done in a separate thread and once completed we invoke the setResult operation on the DeferredResult object. Let’s look at the log output to check that our threads behave as expected:

How is a callable returned from a handler processed in spring?

A Callable returned from a handler method, is processed asynchronously by the Spring container. Whereas, a DeferredResult (which should also be returned from a handler method as well) produces the return value from a thread of its own choice i.e. the developer is responsible for creating a new thread and doing all thread management.