Interface AsyncResponse
public interface AsyncResponse
A new instance of AsyncResponse
may be injected into a resource or sub-resource
method
parameter using the @Suspended
annotation.
- updating suspended state data (time-out value, response ...)
- resuming the suspended request processing
- canceling the suspended request processing
Following example demonstrates the use of the AsyncResponse
for asynchronous HTTP request processing:
@Path("/messages/next") public class MessagingResource { private static final BlockingQueue<AsyncResponse> suspended = new ArrayBlockingQueue<AsyncResponse>(5); @GET public void readMessage(@Suspended AsyncResponse ar) throws InterruptedException { suspended.put(ar); } @POST public String postMessage(final String message) throws InterruptedException { final AsyncResponse ar = suspended.take(); ar.resume(message); // resumes the processing of one GET request return "Message sent"; } }
If the asynchronous response was suspended with a positive timeout value, and has not been explicitly resumed before the timeout has expired, the processing will be resumed once the specified timeout threshold is reached, provided a positive timeout value was set on the response.
By default a timed-out asynchronous response is resumed with a WebApplicationException
that has
HTTP 503 (Service unavailable)
error response status
code set. This default behavior may be overridden by setting
a custom time-out handler
.
- Since:
- 2.0
- Author:
- Marek Potociar
-
Field Summary
Fields Modifier and Type Field Description static long
NO_TIMEOUT
Constant specifying no suspend timeout value. -
Method Summary
Modifier and Type Method Description boolean
cancel()
Cancel the suspended request processing.boolean
cancel(int retryAfter)
Cancel the suspended request processing.boolean
cancel(Date retryAfter)
Cancel the suspended request processing.boolean
isCancelled()
Check if the asynchronous response instance has been cancelled.boolean
isDone()
Check if the processing of a request this asynchronous response instance belongs to has finished.boolean
isSuspended()
Check if the asynchronous response instance is in a suspended state.Collection<Class<?>>
register(Class<?> callback)
Register an asynchronous processing lifecycle callback class to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.Map<Class<?>,Collection<Class<?>>>
register(Class<?> callback, Class<?>... callbacks)
Register asynchronous processing lifecycle callback classes to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.Collection<Class<?>>
register(Object callback)
Register an asynchronous processing lifecycle callback instance to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.Map<Class<?>,Collection<Class<?>>>
register(Object callback, Object... callbacks)
Register an asynchronous processing lifecycle callback instances to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.boolean
resume(Object response)
Resume the suspended request processing using the provided response data.boolean
resume(Throwable response)
Resume the suspended request processing using the provided throwable.boolean
setTimeout(long time, TimeUnit unit)
Set/update the suspend timeout.void
setTimeoutHandler(TimeoutHandler handler)
Set/replace a time-out handler for the suspended asynchronous response.
-
Field Details
-
NO_TIMEOUT
static final long NO_TIMEOUTConstant specifying no suspend timeout value.- See Also:
- Constant Field Values
-
-
Method Details
-
resume
Resume the suspended request processing using the provided response data. The provided response data can be of any Java type that can be returned from aJAX-RS resource method
.The asynchronous response must be still in a
suspended
state for this method to succeed.By executing this method, the request is guaranteed to complete either successfully or with an error. The data processing by the JAX-RS runtime follows the same path as it would for the response data returned synchronously by a JAX-RS resource, except that unmapped exceptions are not re-thrown by JAX-RS runtime to be handled by a hosting I/O container. Instead, any unmapped exceptions are propagated to the hosting I/O container via a container-specific callback mechanism. Depending on the container implementation, propagated unmapped exceptions typically result in an error status being sent to the client and/or the connection being closed.
- Parameters:
response
- data to be sent back in response to the suspended request.- Returns:
true
if the request processing has been resumed, returnsfalse
in case the request processing is notsuspended
and could not be resumed.- See Also:
resume(Throwable)
-
resume
Resume the suspended request processing using the provided throwable. For the provided throwable same rules apply as for an exception thrown by aJAX-RS resource method
.By executing this method, the request is guaranteed to complete either successfully or with an error. The throwable processing by the JAX-RS runtime follows the same path as it would for the response data returned synchronously by a JAX-RS resource, except that unmapped exceptions are not re-thrown by JAX-RS runtime to be handled by a hosting I/O container. Instead, any unmapped exceptions are propagated to the hosting I/O container via a container-specific callback mechanism. Depending on the container implementation, propagated unmapped exceptions typically result in an error status being sent to the client and/or the connection being closed.
- Parameters:
response
- an exception to be raised in response to the suspended request.- Returns:
true
if the response has been resumed, returnsfalse
in case the response is notsuspended
and could not be resumed.- See Also:
resume(Object)
-
cancel
boolean cancel()Cancel the suspended request processing.When a request processing is cancelled using this method, the JAX-RS implementation MUST indicate to the client that the request processing has been cancelled by sending back a
HTTP 503 (Service unavailable)
error response.Invoking a
cancel(...)
method multiple times to cancel request processing has the same effect as canceling the request processing only once. Invoking acancel(...)
method on an asynchronous response instance that has already been cancelled or resumed has no effect and the method call is ignored while returningtrue
, in case the request has been cancelled previously. Otherwise, in case the request has been resumed regularly (using aresume(...) method
) or resumed due to a time-out, method returnsfalse
.- Returns:
true
if the request processing has been cancelled, returnsfalse
in case the request processing is notsuspended
and could not be cancelled and is notcancelled
already.- See Also:
cancel(int)
,cancel(java.util.Date)
-
cancel
boolean cancel(int retryAfter)Cancel the suspended request processing.When a request processing is cancelled using this method, the JAX-RS implementation MUST indicate to the client that the request processing has been cancelled by sending back a
HTTP 503 (Service unavailable)
error response with aRetry-After
header set to the value provided by the method parameter.Invoking a
cancel(...)
method multiple times to cancel request processing has the same effect as canceling the request processing only once. Invoking acancel(...)
method on an asynchronous response instance that has already been cancelled or resumed has no effect and the method call is ignored while returningtrue
, in case the request has been cancelled previously. Otherwise, in case the request has been resumed regularly (using aresume(...) method
) or resumed due to a time-out, method returnsfalse
.- Parameters:
retryAfter
- a decimal integer number of seconds after the response is sent to the client that indicates how long the service is expected to be unavailable to the requesting client.- Returns:
true
if the request processing has been cancelled, returnsfalse
in case the request processing is notsuspended
and could not be cancelled and is notcancelled
already.- See Also:
cancel()
,cancel(java.util.Date)
-
cancel
Cancel the suspended request processing.When a request processing is cancelled using this method, the JAX-RS implementation MUST indicate to the client that the request processing has been cancelled by sending back a
HTTP 503 (Service unavailable)
error response with aRetry-After
header set to the value provided by the method parameter.Invoking a
cancel(...)
method multiple times to cancel request processing has the same effect as canceling the request processing only once. Invoking acancel(...)
method on an asynchronous response instance that has already been cancelled or resumed has no effect and the method call is ignored while returningtrue
, in case the request has been cancelled previously. Otherwise, in case the request has been resumed regularly (using aresume(...) method
) or resumed due to a time-out, method returnsfalse
.- Parameters:
retryAfter
- a date that indicates how long the service is expected to be unavailable to the requesting client.- Returns:
true
if the request processing has been cancelled, returnsfalse
in case the request processing is notsuspended
and could not be cancelled and is notcancelled
already.- See Also:
cancel()
,cancel(int)
-
isSuspended
boolean isSuspended()Check if the asynchronous response instance is in a suspended state. Method returnstrue
if this asynchronous response is still suspended and has not finished processing yet (either by resuming or canceling the response).- Returns:
true
if this asynchronous response is in a suspend state,false
otherwise.- See Also:
isCancelled()
,isDone()
-
isCancelled
boolean isCancelled()Check if the asynchronous response instance has been cancelled. Method returnstrue
if this asynchronous response has been canceled before completion.- Returns:
true
if this task was canceled before completion.- See Also:
isSuspended()
,isDone()
-
isDone
boolean isDone()Check if the processing of a request this asynchronous response instance belongs to has finished. Method returnstrue
if the processing of a request this asynchronous response is bound to is finished.The request processing may be finished due to a normal termination, a suspend timeout, or cancellation -- in all of these cases, this method will return
true
.- Returns:
true
if this execution context has finished processing.- See Also:
isSuspended()
,isCancelled()
-
setTimeout
Set/update the suspend timeout.The new suspend timeout values override any timeout value previously specified. The asynchronous response must be still in a
suspended
state for this method to succeed.- Parameters:
time
- suspend timeout value in the give timeunit
. Value lower or equal to 0 causes the context to suspend indefinitely.unit
- suspend timeout value time unit.- Returns:
true
if the suspend time out has been set, returnsfalse
in case the request processing is not in thesuspended
state.
-
setTimeoutHandler
Set/replace a time-out handler for the suspended asynchronous response.The time-out handler will be invoked when the suspend period of this asynchronous response times out. The job of the time-out handler is to resolve the time-out situation by either
- resuming the suspended response
- cancelling the suspended response
- extending the suspend period by setting a new suspend time-out
Note that in case the response is suspended
indefinitely
, the time-out handler may never be invoked.- Parameters:
handler
- response time-out handler.
-
register
Register an asynchronous processing lifecycle callback class to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.- Parameters:
callback
- callback class.- Returns:
- collection of registered callback interfaces. If the callback class does not implement any recognized callback interfaces, the returned collection will be empty.
- Throws:
NullPointerException
- in case the callback class isnull
.
-
register
Register asynchronous processing lifecycle callback classes to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.- Parameters:
callback
- callback class.callbacks
- additional callback classes.- Returns:
- map of registered classes and the callback interfaces registered for each class. If a callback class does not implement any recognized callback interfaces, the associated collection of registered interfaces for the class will be empty.
- Throws:
NullPointerException
- in case any of the callback classes isnull
.
-
register
Register an asynchronous processing lifecycle callback instance to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.- Parameters:
callback
- callback instance implementing one or more of the recognized callback interfaces.- Returns:
- collection of registered callback interfaces. If the callback class does not implement any recognized callback interfaces, the returned collection will be empty.
- Throws:
NullPointerException
- in case the callback instance isnull
.
-
register
Register an asynchronous processing lifecycle callback instances to receive lifecycle events for the asynchronous response based on the implemented callback interfaces.- Parameters:
callback
- callback instance.callbacks
- additional callback instances.- Returns:
- map of registered classes and the callback interfaces registered for each class. If a callback class does not implement any recognized callback interfaces, the associated collection of registered interfaces for the class will be empty.
- Throws:
NullPointerException
- in case any of the callback instances isnull
.
-