org.springframework.web.context.request.async

Interface CallableProcessingInterceptor

All Known Implementing Classes:

AsyncRequestInterceptor, AsyncRequestInterceptor, AsyncRequestInterceptor, AsyncRequestInterceptor, CallableProcessingInterceptorAdapter, FrameworkServlet.RequestBindingInterceptor, TimeoutCallableProcessingInterceptor

public interface CallableProcessingInterceptor

Intercepts concurrent request handling, where the concurrent result is obtained by executing a Callable on behalf of the application with an AsyncTaskExecutor.

A CallableProcessingInterceptor is invoked before and after the invocation of the Callable task in the asynchronous thread, as well as on timeout from a container thread, or after completing for any reason including a timeout or network error.

As a general rule exceptions raised by interceptor methods will cause async processing to resume by dispatching back to the container and using the Exception instance as the concurrent result. Such exceptions will then be processed through the HandlerExceptionResolver mechanism.

The afterTimeout method can select a value to be used to resume processing.

Since:

3.2

Author:

Rossen Stoyanchev, Rob Winch

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.Object	RESPONSE_HANDLED
static java.lang.Object	RESULT_NONE

Method Summary

Modifier and Type	Method and Description
<T> void	afterCompletion(NativeWebRequest request, java.util.concurrent.Callable<T> task) Invoked from a container thread when async processing completes for any reason including timeout or network error.
<T> void	beforeConcurrentHandling(NativeWebRequest request, java.util.concurrent.Callable<T> task) Invoked before the start of concurrent handling in the original thread in which the Callable is submitted for concurrent handling.
<T> java.lang.Object	handleTimeout(NativeWebRequest request, java.util.concurrent.Callable<T> task) Invoked from a container thread when the async request times out before the Callable task completes.
<T> void	postProcess(NativeWebRequest request, java.util.concurrent.Callable<T> task, java.lang.Object concurrentResult) Invoked after the Callable has produced a result in the async thread in which the Callable is executed.
<T> void	preProcess(NativeWebRequest request, java.util.concurrent.Callable<T> task) Invoked after the start of concurrent handling in the async thread in which the Callable is executed and before the actual invocation of the Callable.

Field Detail

RESULT_NONE

static final java.lang.Object RESULT_NONE

RESPONSE_HANDLED

static final java.lang.Object RESPONSE_HANDLED

Method Detail

beforeConcurrentHandling

<T> void beforeConcurrentHandling(NativeWebRequest request,
                                  java.util.concurrent.Callable<T> task)
                           throws java.lang.Exception

Invoked before the start of concurrent handling in the original thread in which the Callable is submitted for concurrent handling.

This is useful for capturing the state of the current thread just prior to invoking the Callable. Once the state is captured, it can then be transferred to the new Thread in preProcess(NativeWebRequest, Callable). Capturing the state of Spring Security's SecurityContextHolder and migrating it to the new Thread is a concrete example of where this is useful.

Parameters:

request - the current request

task - the task for the current async request

Throws:

java.lang.Exception - in case of errors

preProcess

<T> void preProcess(NativeWebRequest request,
                    java.util.concurrent.Callable<T> task)
             throws java.lang.Exception

Invoked after the start of concurrent handling in the async thread in which the Callable is executed and before the actual invocation of the Callable.

Parameters:

request - the current request

task - the task for the current async request

Throws:

java.lang.Exception - in case of errors

postProcess

<T> void postProcess(NativeWebRequest request,
                     java.util.concurrent.Callable<T> task,
                     java.lang.Object concurrentResult)
              throws java.lang.Exception

Invoked after the Callable has produced a result in the async thread in which the Callable is executed. This method may be invoked later than afterTimeout or afterCompletion depending on when the Callable finishes processing.

Parameters:

request - the current request

task - the task for the current async request

concurrentResult - the result of concurrent processing, which could be a Throwable if the Callable raised an exception

Throws:

java.lang.Exception - in case of errors

handleTimeout

<T> java.lang.Object handleTimeout(NativeWebRequest request,
                                   java.util.concurrent.Callable<T> task)
                            throws java.lang.Exception

Invoked from a container thread when the async request times out before the Callable task completes. Implementations may return a value, including an Exception, to use instead of the value the Callable did not return in time.

Parameters:

request - the current request

task - the task for the current async request

Returns:

a concurrent result value; if the value is anything other than RESULT_NONE or RESPONSE_HANDLED, concurrent processing is resumed and subsequent interceptors are not invoked

Throws:

java.lang.Exception - in case of errors

afterCompletion

<T> void afterCompletion(NativeWebRequest request,
                         java.util.concurrent.Callable<T> task)
                  throws java.lang.Exception

Invoked from a container thread when async processing completes for any reason including timeout or network error.

Parameters:

request - the current request

task - the task for the current async request

Throws:

java.lang.Exception - in case of errors