public abstract class AbstractAsyncServlet extends HttpServlet implements FutureResponseModel
Implementations of AbstractAsyncServlet
decouple the
receiving of a servlet request from the sending of its
response. Responses may be sent in the future through the use of
the AbstractAsyncServlet.notify(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
function. The servlet does not consume any
threads while waiting for AbstractAsyncServlet.notify(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
to be called making it
suitable for scalable proxying to remote systems. The servlet
instance used for sending the response is only guaranteed to be the
same as that used to process the request when
SingleThreadModel
is used.
Stale requests are scavanged based on timeout settings
modifiable through AbstractAsyncServlet.setTimeout(int)
and AbstractAsyncServlet.setScavangeInterval(int)
.
The scavange interval is global to all
AbstractAsyncServlet
s. The timeout period is
per-servlet instance. If a timeout occurs then the AbstractAsyncServlet.doTimeout(weblogic.servlet.http.RequestResponseKey)
method
is called on an appropriate servlet instance, giving implementors a
chance to feedback timeout information to the caller.
Only direct client requests can be used with
AbstractAsyncServlet
, it cannot be used as the target
of request dispatching includes or forwards. It can however be used
to dispatch to forwards and includes that are not instances of
AbstractAsyncServlet
Servlet filters which get applied before
AbstractAsyncServlet
s, will not be able to take
advantage of post processing of the response.
Modifier and Type | Field and Description |
---|---|
static int |
DEFAULT_SCAVANGE_INTERVAL
The default interval period in milliseconds at which requests
will be checked for timeouts.
|
static int |
DEFAULT_TIMEOUT
The default request timeout period in milliseconds.
|
Modifier and Type | Method and Description |
---|---|
protected abstract boolean |
doRequest(RequestResponseKey rrk)
Process the servlet request.
|
protected abstract void |
doResponse(RequestResponseKey rrk,
Object context)
Process the servlet response.
|
protected abstract void |
doTimeout(RequestResponseKey rrk)
Send back a servlet response error when
AbstractAsyncServlet.notify(weblogic.servlet.http.RequestResponseKey, java.lang.Object) is not
called within the timeout period. |
static void |
notify(RequestResponseKey id,
Object context)
notify the servlet implementation that a response should be sent
for the key
id . |
protected void |
service(HttpServletRequest req,
HttpServletResponse rsp)
Implementation of the standard
HttpServlet.service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) method. |
static void |
setScavangeInterval(int period)
Sets the interval period in milliseconds at which requests will
be checked for timeouts.
|
protected void |
setTimeout(int period)
Sets the request timeout period in milliseconds for this
servlet.
|
doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service
destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, init, log, log
public static final int DEFAULT_TIMEOUT
public static final int DEFAULT_SCAVANGE_INTERVAL
protected final void service(HttpServletRequest req, HttpServletResponse rsp) throws IOException, ServletException
HttpServlet.service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
method. This method
cannot be overridden, implementors should instead override
AbstractAsyncServlet.doRequest(weblogic.servlet.http.RequestResponseKey)
and AbstractAsyncServlet.doResponse(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
.service
in class HttpServlet
IOException
ServletException
public static final void notify(RequestResponseKey id, Object context) throws IOException
id
. id
must be the key
provided as an argument to AbstractAsyncServlet.doRequest(weblogic.servlet.http.RequestResponseKey)
. Then
notify>
synchronously sends out the servlet response
after having called AbstractAsyncServlet.doResponse(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
. Notify will pass the
context
object to AbstractAsyncServlet.doResponse(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
, if provided
with one.id
- - the key used to identify the request/response that should be
sent back.context
- - object that will be passed onto AbstractAsyncServlet.doResponse(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
IOException
- - if an input or output error occursprotected abstract boolean doRequest(RequestResponseKey rrk) throws IOException, ServletException
rrk
- the RequestResponseKey, containing the servlet request
and responseIOException
- - if an input or output error occursServletException
- - if the HTTP request cannot be handledprotected abstract void doResponse(RequestResponseKey rrk, Object context) throws IOException, ServletException
doResponse
as AbstractAsyncServlet.doRequest(weblogic.servlet.http.RequestResponseKey)
. If an exception occurs during processing then the
container will arrange for the error to be sent back to the
client. The request and response streams are available in the
RequestResponseKey. This method may get invoked on a different
thread.rrk
- - the RequestResponseKey, containing the servlet request
and responsecontext
- - the context object that was passed to AbstractAsyncServlet.notify(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
IOException
- - if an input or output error occursServletException
- - if the HTTP request cannot be handledprotected abstract void doTimeout(RequestResponseKey rrk) throws IOException, ServletException
AbstractAsyncServlet.notify(weblogic.servlet.http.RequestResponseKey, java.lang.Object)
is not
called within the timeout period. Implementors should override
this method. There is no guarantee that the same servlet instance
is used for processing doTimeout
as AbstractAsyncServlet.doRequest(weblogic.servlet.http.RequestResponseKey)
. The request and response streams are available in
the RequestResponseKey.rrk
- - the RequestResponseKey, containing the servlet request and responseIOException
- - if an input or output error occursServletException
- - if the HTTP request cannot be handledprotected void setTimeout(int period)
GenericServlet.init(javax.servlet.ServletConfig)
method. The new value applies
only to requests started after this method call. To set the
timeout for a specific servlet request, use RequestResponseKey.setTimeout(int)
period
- the timeout period in milliseconds. A timeout
period <= 0 means that requests will never be timed out.public static final void setScavangeInterval(int period)
AbstractAsyncServlet
.period
- the interval period in milliseconds. A timeout
period <= 0 is illegal.