org.eclipse.jetty.server
类 AsyncContinuation

java.lang.Object
  org.eclipse.jetty.server.AsyncContinuation

所有已实现的接口：

AsyncContext, Continuation

public class AsyncContinuation
extends Object
implements AsyncContext, Continuation

Implementation of Continuation and AsyncContext interfaces

嵌套类摘要

class	AsyncContinuation.AsyncEventState
class	AsyncContinuation.AsyncTimeout

字段摘要

protected AbstractHttpConnection

_connection

从接口 javax.servlet.AsyncContext 继承的字段

ASYNC_CONTEXT_PATH, ASYNC_PATH_INFO, ASYNC_QUERY_STRING, ASYNC_REQUEST_URI, ASYNC_SERVLET_PATH

从接口 org.eclipse.jetty.continuation.Continuation 继承的字段

ATTRIBUTE

构造方法摘要

protected

AsyncContinuation()

方法摘要

void	addContinuationListener(ContinuationListener listener) Add a ContinuationListener.
void	addListener(AsyncListener listener) Registers the given AsyncListener with the most recent asynchronous cycle that was started by a call to one of the ServletRequest.startAsync() methods.
void	addListener(AsyncListener listener, ServletRequest request, ServletResponse response) Registers the given AsyncListener with the most recent asynchronous cycle that was started by a call to one of the ServletRequest.startAsync() methods.
void	cancel()
protected void	cancelTimeout()
void	complete() Completes the asynchronous operation that was started on the request that was used to initialze this AsyncContext, closing the response that was used to initialize this AsyncContext.
<T extends AsyncListener> T	createListener(Class<T> clazz) Instantiates the given AsyncListener class.
void	dispatch() Dispatches the request and response objects of this AsyncContext to the servlet container.
void	dispatch(ServletContext context, String path) Dispatches the request and response objects of this AsyncContext to the given path scoped to the given context.
void	dispatch(String path) Dispatches the request and response objects of this AsyncContext to the given path.
protected void	doComplete(Throwable ex)
protected void	expired()
AsyncContinuation.AsyncEventState	getAsyncEventState()
Object	getAttribute(String name) Get a request attribute.
Request	getBaseRequest()
ContextHandler	getContextHandler()
ServletRequest	getRequest() Gets the request that was used to initialize this AsyncContext by calling ServletRequest.startAsync() or ServletRequest.startAsync(ServletRequest, ServletResponse).
ServletResponse	getResponse() Gets the response that was used to initialize this AsyncContext by calling ServletRequest.startAsync() or ServletRequest.startAsync(ServletRequest, ServletResponse).
ServletResponse	getServletResponse() Get the suspended response.
String	getStatusString()
long	getTimeout() Gets the timeout (in milliseconds) for this AsyncContext.
protected boolean	handling()
boolean	hasOriginalRequestAndResponse() Checks if this AsyncContext was initialized with the original or application-wrapped request and response objects.
boolean	isAsync()
boolean	isAsyncStarted()
boolean	isComplete()
boolean	isCompleting()
boolean	isContinuation()
boolean	isDispatchable()
boolean	isExpired()
boolean	isInitial()
boolean	isResponseWrapped() Is the suspended response wrapped.
boolean	isResumed()
boolean	isSuspended()
boolean	isSuspending()
protected void	recycle()
void	removeAttribute(String name) Remove a request attribute.
void	resume() Resume a suspended request.
protected void	scheduleDispatch()
protected void	scheduleTimeout()
void	setAttribute(String name, Object attribute) Set a request attribute.
protected void	setConnection(AbstractHttpConnection connection)
void	setTimeout(long ms) Sets the timeout (in milliseconds) for this AsyncContext.
void	start(Runnable run) Causes the container to dispatch a thread, possibly from a managed thread pool, to run the specified Runnable.
protected void	startAsync()
protected void	startAsync(ServletContext context, ServletRequest request, ServletResponse response)
void	suspend() Suspend the processing of the request and associated ServletResponse.
void	suspend(ServletResponse response) Suspend the processing of the request and associated ServletResponse.
String	toString()
void	undispatch() Undispatch the request.
protected boolean	unhandle() Signal that the HttpConnection has finished handling the request.

从类 java.lang.Object 继承的方法

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

字段详细信息

_connection

protected AbstractHttpConnection _connection

构造方法详细信息

AsyncContinuation

protected AsyncContinuation()

方法详细信息

setConnection

protected void setConnection(AbstractHttpConnection connection)

addListener

public void addListener(AsyncListener listener)

从接口 AsyncContext 复制的描述

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

The given AsyncListener will receive an AsyncEvent when the asynchronous cycle completes successfully, times out, or results in an error.

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

指定者：

接口 AsyncContext 中的 addListener

参数：

listener - the AsyncListener to be registered

addListener

public void addListener(AsyncListener listener,
                        ServletRequest request,
                        ServletResponse response)

从接口 AsyncContext 复制的描述

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

The given AsyncListener will receive an AsyncEvent when the asynchronous cycle completes successfully, times out, or results in an error.

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

The given ServletRequest and ServletResponse objects will be made available to the given AsyncListener via the getSuppliedRequest and getSuppliedResponse methods, respectively, of the AsyncEvent delivered to it. These objects should not be read from or written to, respectively, at the time the AsyncEvent is delivered, because additional wrapping may have occurred since the given AsyncListener was registered, but may be used in order to release any resources associated with them.

指定者：

接口 AsyncContext 中的 addListener

参数：

listener - the AsyncListener to be registered

request - the ServletRequest that will be included in the AsyncEvent

response - the ServletResponse that will be included in the AsyncEvent

addContinuationListener

public void addContinuationListener(ContinuationListener listener)

从接口 Continuation 复制的描述

Add a ContinuationListener.

指定者：

接口 Continuation 中的 addContinuationListener

setTimeout

public void setTimeout(long ms)

从接口 AsyncContext 复制的描述

Sets the timeout (in milliseconds) for this AsyncContext.

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

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

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

指定者：

接口 AsyncContext 中的 setTimeout

指定者：

接口 Continuation 中的 setTimeout

参数：

ms - the timeout in milliseconds

getTimeout

public long getTimeout()

从接口 AsyncContext 复制的描述

Gets the timeout (in milliseconds) for this AsyncContext.

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

A timeout value of zero or less indicates no timeout.

指定者：

接口 AsyncContext 中的 getTimeout

返回：

the timeout in milliseconds

getAsyncEventState

public AsyncContinuation.AsyncEventState getAsyncEventState()

isResponseWrapped

public boolean isResponseWrapped()

从接口 Continuation 复制的描述

Is the suspended response wrapped.

Filters that wrap the response object should check this method to determine if they should destroy/finish the wrapped response. If the request was suspended with a call to Continuation.suspend(ServletResponse) that passed the wrapped response, then the filter should register a ContinuationListener to destroy/finish the wrapped response during a call to ContinuationListener.onComplete(Continuation).

指定者：

接口 Continuation 中的 isResponseWrapped

返回：

True if Continuation.suspend(ServletResponse) has been passed a ServletResponseWrapper instance.

另请参见：

Continuation.isResponseWrapped()

isInitial

public boolean isInitial()

指定者：

接口 Continuation 中的 isInitial

返回：

true while the request is within the initial dispatch to the filter chain and/or servlet. Will return false once the calling thread has returned to the container after suspend has been called and during any subsequent redispatch.

isContinuation

public boolean isContinuation()

isSuspended

public boolean isSuspended()

指定者：

接口 Continuation 中的 isSuspended

返回：

true after Continuation.suspend() has been called and before the request has been redispatched due to being resumed, completed or timed out.

isSuspending

public boolean isSuspending()

isDispatchable

public boolean isDispatchable()

toString

public String toString()

覆盖：

类 Object 中的 toString

getStatusString

public String getStatusString()

handling

protected boolean handling()

返回：

false if the handling of the request should not proceed

unhandle

protected boolean unhandle()

Signal that the HttpConnection has finished handling the request. For blocking connectors, this call may block if the request has been suspended (startAsync called).

返回：

true if handling is complete, false if the request should be handled again (eg because of a resume that happened before unhandle was called)

dispatch

public void dispatch()

从接口 AsyncContext 复制的描述

Dispatches the request and response objects of this AsyncContext to the servlet container.

If the asynchronous cycle was started with ServletRequest.startAsync(ServletRequest, ServletResponse), and the request passed is an instance of HttpServletRequest, then the dispatch is to the URI returned by HttpServletRequest.getRequestURI(). Otherwise, the dispatch is to the URI of the request when it was last dispatched by the container.

The following sequence illustrates how this will work:

 // REQUEST dispatch to /url/A
 AsyncContext ac = request.startAsync();
 ...
 ac.dispatch(); // ASYNC dispatch to /url/A
 
 // FORWARD dispatch to /url/B
 getRequestDispatcher("/url/B").forward(request,response);
 // Start async operation from within the target of the FORWARD
 // dispatch
 ac = request.startAsync();
 ...
 ac.dispatch(); // ASYNC dispatch to /url/A
 
 // FORWARD dispatch to /url/B
 getRequestDispatcher("/url/B").forward(request,response);
 // Start async operation from within the target of the FORWARD
 // dispatch
 ac = request.startAsync(request,response);
 ...
 ac.dispatch(); // ASYNC dispatch to /url/B
 

This method returns immediately after passing the request and response objects to a container managed thread, on which the dispatch operation will be performed. 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 ServletRequest.startAsync() or ServletRequest.startAsync(ServletRequest, ServletResponse) 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:

1. Invoke, at their onError method, all AsyncListener instances registered with the ServletRequest for which this AsyncContext was created, and make the caught Throwable available via AsyncEvent.getThrowable().
2. If none of the listeners called AsyncContext.complete() or any of the AsyncContext.dispatch() methods, perform an error dispatch with a status code equal to HttpServletResponse.SC_INTERNAL_SERVER_ERROR, and make the above Throwable available as the value of the RequestDispatcher.ERROR_EXCEPTION request attribute.
3. If no matching error page was found, or the error page did not call AsyncContext.complete() or any of the AsyncContext.dispatch() methods, call AsyncContext.complete().

There can be at most one asynchronous dispatch operation per asynchronous cycle, which is started by a call to one of the ServletRequest.startAsync() methods. Any attempt to perform an additional asynchronous dispatch operation within the same asynchronous cycle will result in an IllegalStateException. If startAsync is subsequently called on the dispatched request, then any of the dispatch or AsyncContext.complete() methods may be called.

指定者：

接口 AsyncContext 中的 dispatch

另请参见：

ServletRequest.getDispatcherType()

expired

protected void expired()

complete

public void complete()

从接口 AsyncContext 复制的描述

Completes the asynchronous operation that was started on the request that was used to initialze this AsyncContext, closing the response that was used to initialize this AsyncContext.

Any listeners of type AsyncListener that were registered with the ServletRequest for which this AsyncContext was created will be invoked at their onComplete method.

It is legal to call this method any time after a call to ServletRequest.startAsync() or ServletRequest.startAsync(ServletRequest, ServletResponse), 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 AsyncListener.onComplete(AsyncEvent) will be delayed) until after the container-initiated dispatch has returned to the container.

指定者：

接口 AsyncContext 中的 complete

指定者：

接口 Continuation 中的 complete

另请参见：

Continuation.suspend()

createListener

public <T extends AsyncListener> T createListener(Class<T> clazz)
                                       throws ServletException

从接口 AsyncContext 复制的描述

Instantiates the given AsyncListener class.

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

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

This method supports resource injection if the given clazz represents a Managed Bean. See the Java EE platform and JSR 299 specifications for additional details about Managed Beans and resource injection.

This method supports any annotations applicable to AsyncListener.

指定者：

接口 AsyncContext 中的 createListener

参数：

clazz - the AsyncListener class to instantiate

返回：

the new AsyncListener instance

抛出：

ServletException - if the given clazz fails to be instantiated

doComplete

protected void doComplete(Throwable ex)

recycle

protected void recycle()

cancel

public void cancel()

scheduleDispatch

protected void scheduleDispatch()

scheduleTimeout

protected void scheduleTimeout()

cancelTimeout

protected void cancelTimeout()

isCompleting

public boolean isCompleting()

isComplete

public boolean isComplete()

isAsyncStarted

public boolean isAsyncStarted()

isAsync

public boolean isAsync()

dispatch

public void dispatch(ServletContext context,
                     String path)

从接口 AsyncContext 复制的描述

Dispatches the request and response objects of this AsyncContext to the given path scoped to the given context.

The path parameter is interpreted in the same way as in ServletRequest.getRequestDispatcher(String), except that it is scoped to the given context.

All path related query methods of the request must reflect the dispatch target, while the original request URI, context path, path info, servlet path, and query string may be recovered from the AsyncContext.ASYNC_REQUEST_URI, AsyncContext.ASYNC_CONTEXT_PATH, AsyncContext.ASYNC_PATH_INFO, AsyncContext.ASYNC_SERVLET_PATH, and AsyncContext.ASYNC_QUERY_STRING attributes of the request. These attributes will always reflect the original path elements, even under repeated dispatches.

There can be at most one asynchronous dispatch operation per asynchronous cycle, which is started by a call to one of the ServletRequest.startAsync() methods. Any attempt to perform an additional asynchronous dispatch operation within the same asynchronous cycle will result in an IllegalStateException. If startAsync is subsequently called on the dispatched request, then any of the dispatch or AsyncContext.complete() methods may be called.

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

指定者：

接口 AsyncContext 中的 dispatch

参数：

context - the ServletContext of the dispatch target

path - the path of the dispatch target, scoped to the given ServletContext

另请参见：

ServletRequest.getDispatcherType()

dispatch

public void dispatch(String path)

从接口 AsyncContext 复制的描述

Dispatches the request and response objects of this AsyncContext to the given path.

The path parameter is interpreted in the same way as in ServletRequest.getRequestDispatcher(String), within the scope of the ServletContext from which this AsyncContext was initialized.

All path related query methods of the request must reflect the dispatch target, while the original request URI, context path, path info, servlet path, and query string may be recovered from the AsyncContext.ASYNC_REQUEST_URI, AsyncContext.ASYNC_CONTEXT_PATH, AsyncContext.ASYNC_PATH_INFO, AsyncContext.ASYNC_SERVLET_PATH, and AsyncContext.ASYNC_QUERY_STRING attributes of the request. These attributes will always reflect the original path elements, even under repeated dispatches.

There can be at most one asynchronous dispatch operation per asynchronous cycle, which is started by a call to one of the ServletRequest.startAsync() methods. Any attempt to perform an additional asynchronous dispatch operation within the same asynchronous cycle will result in an IllegalStateException. If startAsync is subsequently called on the dispatched request, then any of the dispatch or AsyncContext.complete() methods may be called.

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

指定者：

接口 AsyncContext 中的 dispatch

参数：

path - the path of the dispatch target, scoped to the ServletContext from which this AsyncContext was initialized

另请参见：

ServletRequest.getDispatcherType()

getBaseRequest

public Request getBaseRequest()

getRequest

public ServletRequest getRequest()

从接口 AsyncContext 复制的描述

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

指定者：

接口 AsyncContext 中的 getRequest

返回：

the request that was used to initialize this AsyncContext

getResponse

public ServletResponse getResponse()

从接口 AsyncContext 复制的描述

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

指定者：

接口 AsyncContext 中的 getResponse

返回：

the response that was used to initialize this AsyncContext

start

public void start(Runnable run)

从接口 AsyncContext 复制的描述

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.

指定者：

接口 AsyncContext 中的 start

参数：

run - the asynchronous handler

hasOriginalRequestAndResponse

public boolean hasOriginalRequestAndResponse()

从接口 AsyncContext 复制的描述

Checks if this AsyncContext 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.

指定者：

接口 AsyncContext 中的 hasOriginalRequestAndResponse

返回：

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

getContextHandler

public ContextHandler getContextHandler()

isResumed

public boolean isResumed()

指定者：

接口 Continuation 中的 isResumed

返回：

true if the request has been redispatched by a call to Continuation.resume(). Returns false after any subsequent call to suspend

另请参见：

Continuation.isResumed()

isExpired

public boolean isExpired()

指定者：

接口 Continuation 中的 isExpired

返回：

true after a request has been redispatched as the result of a timeout. Returns false after any subsequent call to suspend.

另请参见：

Continuation.isExpired()

resume

public void resume()

从接口 Continuation 复制的描述

Resume a suspended request.

This method can be called by any thread that has been passed a reference to a continuation. When called the request is redispatched to the normal filter chain and servlet processing with Continuation.isInitial() false.

If resume is called before a suspended request is returned to the container (ie the thread that called Continuation.suspend() is still within the filter chain and/or servlet service method), then the resume does not take effect until the call to the filter chain and/or servlet returns to the container. In this case both Continuation.isSuspended() and Continuation.isResumed() return true. Multiple calls to resume are ignored.

Typically resume() is used after a call to Continuation.suspend() with no arguments. The dispatch after a resume call will use the original request and response objects, even if Continuation.suspend(ServletResponse) had been passed a wrapped response.

指定者：

接口 Continuation 中的 resume

另请参见：

Continuation.resume()

startAsync

protected void startAsync(ServletContext context,
                          ServletRequest request,
                          ServletResponse response)

startAsync

protected void startAsync()

suspend

public void suspend(ServletResponse response)

从接口 Continuation 复制的描述

Suspend the processing of the request and associated ServletResponse.

After this method has been called, the lifecycle of the request will be extended beyond the return to the container from the Servlet.service(ServletRequest, ServletResponse) method and Filter.doFilter(ServletRequest, ServletResponse, FilterChain) calls. When a suspended request is returned to the container after a dispatch, then the container will not commit the associated response (unless an exception other than ContinuationThrowable is thrown).

When the thread calling the filter chain and/or servlet has returned to the container with a suspended request, the thread is freed for other tasks and the request is held until either:

• a call to Continuation.resume().
• a call to Continuation.complete().
• the timeout expires.

Typically suspend with a response argument is uses when a call to Continuation.complete() is expected. If a call to Continuation.resume() is expected, then the Continuation.suspend() method should be used instead of this method.

Filters that may wrap the response object should check Continuation.isResponseWrapped() to decide if they should destroy/finish the wrapper. If Continuation.isResponseWrapped() returns true, then the wrapped request has been passed to the asynchronous handler and the wrapper should not be destroyed/finished until after a call to Continuation.complete() (potentially using a ContinuationListener.onComplete(Continuation) listener).

指定者：

接口 Continuation 中的 suspend

参数：

response - The response to return via a call to Continuation.getServletResponse()

另请参见：

Continuation.suspend()

suspend

public void suspend()

从接口 Continuation 复制的描述

Suspend the processing of the request and associated ServletResponse.

After this method has been called, the lifecycle of the request will be extended beyond the return to the container from the Servlet.service(ServletRequest, ServletResponse) method and Filter.doFilter(ServletRequest, ServletResponse, FilterChain) calls. When a suspended request is returned to the container after a dispatch, then the container will not commit the associated response (unless an exception other than ContinuationThrowable is thrown).

When the thread calling the filter chain and/or servlet has returned to the container with a suspended request, the thread is freed for other tasks and the request is held until either:

• a call to Continuation.resume().
• a call to Continuation.complete().
• the timeout expires.

Typically suspend with no arguments is uses when a call to Continuation.resume() is expected. If a call to Continuation.complete() is expected, then the Continuation.suspend(ServletResponse) method should be used instead of this method.

指定者：

接口 Continuation 中的 suspend

另请参见：

Continuation.suspend()

getServletResponse

public ServletResponse getServletResponse()

从接口 Continuation 复制的描述

Get the suspended response.

指定者：

接口 Continuation 中的 getServletResponse

返回：

the ServletResponse passed to Continuation.suspend(ServletResponse).

另请参见：

Continuation.getServletResponse()

getAttribute

public Object getAttribute(String name)

从接口 Continuation 复制的描述

Get a request attribute. This method is a convenience method to call the ServletRequest.getAttribute(String) method on the associated request object. This is a thread safe call and may be called by any thread.

指定者：

接口 Continuation 中的 getAttribute

参数：

name - the attribute name

返回：

the attribute value

另请参见：

Continuation.getAttribute(java.lang.String)

removeAttribute

public void removeAttribute(String name)

从接口 Continuation 复制的描述

Remove a request attribute. This method is a convenience method to call the ServletRequest.removeAttribute(String) method on the associated request object. This is a thread safe call and may be called by any thread.

指定者：

接口 Continuation 中的 removeAttribute

参数：

name - the attribute name

另请参见：

Continuation.removeAttribute(java.lang.String)

setAttribute

public void setAttribute(String name,
                         Object attribute)

从接口 Continuation 复制的描述

Set a request attribute. This method is a convenience method to call the ServletRequest.setAttribute(String, Object) method on the associated request object. This is a thread safe call and may be called by any thread.

指定者：

接口 Continuation 中的 setAttribute

参数：

name - the attribute name

attribute - the attribute value

另请参见：

Continuation.setAttribute(java.lang.String, java.lang.Object)

undispatch

public void undispatch()

从接口 Continuation 复制的描述

Undispatch the request.

This method can be called on a suspended continuation in order to exit the dispatch to the filter/servlet by throwing a ContinuationThrowable which is caught either by the container or the ContinuationFilter. This is an alternative to simply returning from the dispatch in the case where filters in the filter chain may not be prepared to handle a suspended request.

This method should only be used as a last resort and a normal return is a prefereable solution if filters can be updated to handle that case.

指定者：

接口 Continuation 中的 undispatch

另请参见：

Continuation.undispatch()