javax.portlet

Interface PortletAsyncContext

All Known Implementing Classes:

PortletAsyncContextWrapper

public interface PortletAsyncContext

Class representing the execution context for an asynchronous operation that was initiated on a ResourceRequest.

Portlet asynchronous support is modeled after servlet asynchronous support, and in general, the portlet async methods behave in the same manner as their AsyncContext analog.

A PortletAsyncContext is created and initialized by a call to ResourceRequest#startAsync() or ResourceRequest#startAsync(ServletRequest, ServletResponse). Repeated invocations of these methods will return the same PortletAsyncContext instance, reinitialized as appropriate.

In the event that an asynchronous operation times out, the container will invoke the onTimeout method of all PortletAsyncListener instances registered with the PortletAsyncContext on which the asynchronous operation was initiated. If none of the listeners call complete() or any of the dispatch() methods, the portlet container will complete the request on behalf of the application and may respond with error information.

Since:

3.0

See Also:

AsyncContext, PortletAsyncListener, PortletAsyncEvent

Method Summary

Modifier and Type	Method and Description
void	addListener(PortletAsyncListener listener) Registers the given PortletAsyncListener with the most recent asynchronous cycle that was started by a call to one of the ResourceRequest.startAsync() methods.
void	addListener(PortletAsyncListener listener, ResourceRequest request, ResourceResponse response) Registers the given PortletAsyncListener with the most recent asynchronous cycle that was started by a call to one of the ResourceRequest.startAsync() methods.
void	complete() Completes the PortletAsynchronous operation and closes the response associated with this PortletAsyncContext object.
<T extends PortletAsyncListener> T	createPortletAsyncListener(Class<T> cls) Instantiates the given PortletAsyncListener class.
void	dispatch() Dispatches the request and response objects of this PortletAsyncContext to the portlet container.
void	dispatch(String path) Dispatches the request and response objects of this PortletAsyncContext to the given path within the PortletContext.
ResourceRequest	getResourceRequest() Gets the request that was used to initialize this PortletAsyncContext by calling ResourceRequest.startAsync() or ResourceRequest.startAsync(ServletRequest, ServletResponse).
ResourceResponse	getResourceResponse() Gets the response that was used to initialize this PortletAsyncContext by calling ResourceRequest.startAsync() or ResourceRequest.startAsync(ServletRequest, ServletResponse).
long	getTimeout() Gets the timeout (in milliseconds) for this PortletAsyncContext.
boolean	hasOriginalRequestAndResponse() Checks if this PortletAsyncContext was initialized with the original or application-wrapped request and response objects.
void	setTimeout(long time) Sets the timeout (in milliseconds) for this PortletAsyncContext.
void	start(Runnable run) Causes the container to dispatch a thread, possibly from a managed thread pool, to run the specified Runnable.

Method Detail

addListener

void addListener(PortletAsyncListener listener)
          throws IllegalStateException

Registers the given PortletAsyncListener with the most recent asynchronous cycle that was started by a call to one of the ResourceRequest.startAsync() methods.

The given PortletAsyncListener will receive an PortletAsyncEvent when the asynchronous cycle completes successfully, times out, results in an error, or a new asynchronous cycle is being initiated via one of the ResourceRequest.startAsync() methods.

PortletAsyncListener instances will be notified in the order in which they were added.

When one of the listener methods is invoked, the PortletAsyncListener getSuppliedRequest() and getSuppliedResponse() methods of the PortletAsyncEvent object will return null.

Parameters:

listener - the listener to be added

Throws:

IllegalStateException - if this method is called after the container-initiated dispatch, during which one of the ResourceRequest.startAsync() methods was called, has returned to the container

See Also:

PortletAsyncListener, PortletAsyncEvent

addListener

void addListener(PortletAsyncListener listener,
                 ResourceRequest request,
                 ResourceResponse response)
          throws IllegalStateException

Registers the given PortletAsyncListener with the most recent asynchronous cycle that was started by a call to one of the ResourceRequest.startAsync() methods.

The given PortletAsyncListener will receive an PortletAsyncEvent when the asynchronous cycle completes successfully, times out, results in an error, or a new asynchronous cycle is being initiated via one of the ResourceRequest.startAsync() methods.

PortletAsyncListener instances will be notified in the order in which they were added.

The given ResourceRequest and ResourceResponse objects will be made available to the given PortletAsyncListener via the getSuppliedRequest and getSuppliedResponse methods, respectively, of the PortletAsyncEvent delivered to it. These objects should not be read from or written to at the time the PortletAsyncEvent is delivered, because additional wrapping may have occurred since the given PortletAsyncListener was registered. However, they may be used to release any resources associated with them.

Parameters:

listener - the listener to be added

request - the request object to be included in the PortletAsyncEvent

response - the response object to be included in the PortletAsyncEvent

Throws:

IllegalStateException - if this method is called after the container-initiated dispatch, during which one of the ResourceRequest.startAsync() methods was called, has returned to the container

See Also:

PortletAsyncListener, PortletAsyncEvent

complete

void complete()
       throws IllegalStateException

Completes the PortletAsynchronous operation and closes the response associated with this PortletAsyncContext object.

The onComplete method of any registered listeners that were registered with the PortletAsyncContext object for this asynchronous cycle will be invoked.

It is legal to call this method any time after a call to ResourceRequest#startAsync() or ResourceRequest#startAsync(ResourceRequest, ResourceResponse), and before a call to one of the dispatch methods of this class. If this method is called before the container-initiated dispatch that called startAsync has returned to the container, then the call will not take effect (and any invocations of PortletAsyncListener#onComplete(PortletAsyncEvent) will be delayed) until after the container-initiated dispatch has returned to the container.

Throws:

IllegalStateException - if this method is called before an asynchronous processing cycle was started, after it has already been completed, or after a call to one of the dispatch() methods

createPortletAsyncListener

<T extends PortletAsyncListener> T createPortletAsyncListener(Class<T> cls)
                                                       throws PortletException

Instantiates the given PortletAsyncListener class.

The returned PortletAsyncListener instance may be further customized before it is registered with this PortletAsyncContext via a call to one of the addListener methods.

The given PortletAsyncListener class must define a zero argument constructor, which is used to instantiate it.

This method supports resource injection if contextual support is available, and if the given class represents a Managed Bean. See the Java EE platform and JSR 299 specifications for additional details about Managed Beans and resource injection.

Parameters:

cls - the class to be instantiated

Returns:

the instantiated class

Throws:

PortletException - if the given class cannot be instantiated

dispatch

void dispatch()
       throws IllegalStateException

Dispatches the request and response objects of this PortletAsyncContext to the portlet container.

The portlet container will dispatch the the request and response to the portlet resource method in which the first asynchronous processing cycle was initiated.

This method returns immediately after passing the request and response objects to a container managed thread which will perform the dispatch operation. If this method is called before the container-initiated dispatch that called startAsync has returned to the container, the dispatch operation will be delayed until after the container-initiated dispatch has returned to the container.

The dispatcher type of the request is set to DispatcherType.ASYNC. Unlike forward dispatches, the response buffer and headers will not be reset, and it is legal to dispatch even if the response has already been committed.

Control over the request and response is delegated to the dispatch target, and the response will be closed when the dispatch target has completed execution, unless ResourceRequest#startAsync() or ResourceRequest#startAsync(ResourceRequest, ResourceResponse) are called.

Any errors or exceptions that may occur during the execution of this method must be caught and handled by the container as follows:

• Invoke the onError method of all PortletAsyncListener instances registered with this PortletAsyncContext and make the caught Throwable available via PortletAsyncEvent#getThrowable.
• If none of the listeners called complete() or any of the dispatch() methods, set the status code equal to HttpResourceResponse.SC_INTERNAL_SERVER_ERROR, make the Throwable leading to the error available as the value of the RequestDispatcher.ERROR_EXCEPTION request attribute, and perform an error dispatch to generate a platform-specific error message.
• Complete the asynchronous processing cycle by calling complete().

There can be at most one asynchronous dispatch operation per asynchronous cycle, which is started by a call to one of the ResourceRequest#startAsync methods. Any attempt to perform an additional asynchronous dispatch operation within the same asynchronous cycle will result in an IllegalStateException. When the container performs the dispatch operation, startAsync() may be invoked on the dispatched request to initiate a new asynchronous processing cycle, after which any of the dispatch methods or the complete() method may be called.

Throws:

IllegalStateException - if called before an asynchronous processing cycle has been started, if one of the dispatch methods has been called but the startAsync method has not been called during the resulting dispatch, or if complete() was called

dispatch

void dispatch(String path)
       throws IllegalStateException

Dispatches the request and response objects of this PortletAsyncContext to the given path within the PortletContext.

The path parameter is interpreted in the same way as in PortletContext#getRequestDispatcher(String) scoped to the current portlet context.

There can be at most one asynchronous dispatch operation per asynchronous cycle, which is started by a call to one of the ResourceRequest#startAsync methods. Any attempt to perform an additional asynchronous dispatch operation within the same asynchronous cycle will result in an IllegalStateException. When the container performs the dispatch operation, startAsync() may be invoked on the dispatched request to initiate a new asynchronous processing cycle, after which any of the dispatch methods or the complete() method may be called.

See dispatch() for additional details, including error handling.

Parameters:

path - the path of the dispatch target, scoped to the PortletContext from which this PortletAsyncContext was initialized

Throws:

IllegalStateException - if called before an asynchronous processing cycle has been started, if one of the dispatch methods has been called but the startAsync method has not been called during the resulting dispatch, or if complete() was called

getResourceRequest

ResourceRequest getResourceRequest()
                            throws IllegalStateException

Gets the request that was used to initialize this PortletAsyncContext by calling ResourceRequest.startAsync() or ResourceRequest.startAsync(ServletRequest, ServletResponse).

Returns:

The resource request object

Throws:

IllegalStateException - if one of the dispatch methods has been called but the startAsync method has not been called during the resulting dispatch, or if complete() was called

getResourceResponse

ResourceResponse getResourceResponse()
                              throws IllegalStateException

Gets the response that was used to initialize this PortletAsyncContext by calling ResourceRequest.startAsync() or ResourceRequest.startAsync(ServletRequest, ServletResponse).

Returns:

The resource response object

Throws:

IllegalStateException - if one of the dispatch methods has been called but the startAsync method has not been called during the resulting dispatch, or if complete() was called

getTimeout

long getTimeout()

Gets the timeout (in milliseconds) for this PortletAsyncContext.

This method returns the container's default timeout for asynchronous operations, or the timeout value passed to the most recent invocation of setTimeout(long).

A timeout value of zero or less indicates no timeout.

Returns:

the timeout in milliseconds

hasOriginalRequestAndResponse

boolean hasOriginalRequestAndResponse()

Checks if this PortletAsyncContext was initialized with the original or application-wrapped request and response objects.

This information may be used by filters invoked in the outbound direction, after a request was put into asynchronous mode, to determine whether any request and/or response wrappers that they added during their inbound invocation need to be preserved for the duration of the asynchronous operation, or may be released.

Returns:

true if this PortletAsyncContext was initialized with the original request and response objects by calling ResourceRequest.startAsync(), or if it was initialized by calling ResourceRequest.startAsync(ResourceRequest, ResourceResponse), and neither the ResourceRequest nor ResourceResponse arguments carried any application-provided wrappers; false otherwise

setTimeout

void setTimeout(long time)

Sets the timeout (in milliseconds) for this PortletAsyncContext.

The timeout applies to this PortletAsyncContext once the container-initiated dispatch during which one of the ResourceRequest.startAsync() methods was called has returned to the container.

The timeout will expire if neither the complete() method nor any of the dispatch methods are called. A timeout value of zero or less indicates no timeout.

If setTimeout(long) is not called, then the container's default timeout, which is available via a call to getTimeout(), will apply.

The default value is 30000 ms.

Parameters:

time - the timeout in milliseconds

start

void start(Runnable run)
    throws IllegalStateException

Causes the container to dispatch a thread, possibly from a managed thread pool, to run the specified Runnable. The container may propagate appropriate contextual information to the Runnable.

Parameters:

run - the asynchronous handler

Throws:

IllegalStateException - if this method is called before an asynchronous processing cycle was started, after it has already been completed, or after a call to one of the dispatch() methods