Package org.springframework.web.context.request.async

Interface CallableProcessingInterceptor

All Known Implementing Classes:

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/error 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 handleTimeout 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	Description
static final Object	RESPONSE_HANDLED	Constant indicating that the response has been handled by this interceptor without a result and that no further interceptors are to be invoked.
static final Object	RESULT_NONE	Constant indicating that no result has been determined by this interceptor, giving subsequent interceptors a chance.

Method Summary

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

RESULT_NONE

static final Object RESULT_NONE

Constant indicating that no result has been determined by this interceptor, giving subsequent interceptors a chance.

See Also:

• handleTimeout(org.springframework.web.context.request.NativeWebRequest, java.util.concurrent.Callable<T>)
• handleError(org.springframework.web.context.request.NativeWebRequest, java.util.concurrent.Callable<T>, java.lang.Throwable)

RESPONSE_HANDLED

static final Object RESPONSE_HANDLED

Constant indicating that the response has been handled by this interceptor without a result and that no further interceptors are to be invoked.

See Also:

• handleTimeout(org.springframework.web.context.request.NativeWebRequest, java.util.concurrent.Callable<T>)
• handleError(org.springframework.web.context.request.NativeWebRequest, java.util.concurrent.Callable<T>, java.lang.Throwable)

Method Details

beforeConcurrentHandling

default <T> void beforeConcurrentHandling(NativeWebRequest request,
 Callable<T> task)
                                   throws 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.

The default implementation is empty.

Parameters:

request - the current request

task - the task for the current async request

Throws:

Exception - in case of errors

preProcess

default <T> void preProcess(NativeWebRequest request,
 Callable<T> task)
                     throws 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.

The default implementation is empty.

Parameters:

request - the current request

task - the task for the current async request

Throws:

Exception - in case of errors

postProcess

default <T> void postProcess(NativeWebRequest request,
 Callable<T> task,
 @Nullable
 Object concurrentResult)
                      throws 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.

The default implementation is empty.

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:

Exception - in case of errors

handleTimeout

default <T> Object handleTimeout(NativeWebRequest request,
 Callable<T> task)
                          throws 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.

The default implementation always returns RESULT_NONE.

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:

Exception - in case of errors

handleError

default <T> Object handleError(NativeWebRequest request,
 Callable<T> task,
 Throwable t)
                        throws Exception

Invoked from a container thread when an error occurred while processing the async request 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.

The default implementation always returns RESULT_NONE.

Parameters:

request - the current request

task - the task for the current async request

t - the error that occurred while request processing

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:

Exception - in case of errors

Since:

5.0

afterCompletion

default <T> void afterCompletion(NativeWebRequest request,
 Callable<T> task)
                          throws Exception

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

The default implementation is empty.

Parameters:

request - the current request

task - the task for the current async request

Throws:

Exception - in case of errors