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Integration Spring (session/request) scoped Beans into RAP [message #81565]

Sat, 05 April 2008 13:16

Stefan Hansel

Messages: 103
Registered: July 2009

Senior Member

I'm currently thinking of integrating
Spring with RAP. 
 As long as just normal singleton or
prototype beans are uses, this works quite well.
 
 On additional useful feature of Spring
is the possibility to scope beans at the request or session level, which
makes life a lot easier.
 (<a href=" http://static.springframework.org/spring/docs/2.5.x/referenc e/beans.html#beans-factory-scopes-other-web-configuration"> http://static.springframework.org/spring/docs/2.5.x/referenc e/beans.html#beans-factory-scopes-other-web-configuration</a>)
 
 Within RAP one could discuss how a 'request'
is mapped to the asynchronious AJAX world - I'd like to define it as every
RAP-Server-Roundtrip - so if I click on a RAP-Button (which has a listener
installed) and then somethings happens - that would be a request.
 
 In a normal web-application one would
install an additional Spring-ServletRequestListener (which in turn puts
the current request in a ThreadLocal). Springs Bean-Proxies (accessed within
the servlet-thread) are then aware  of requests and sessions.
 
 With RAP things get a little bit complicated,
because the actual application code is not run in the servlet thread but
a special UIThread.
 Springs Bean-Proxies then can't find
their current ServletRequest in their ThreadLocal and throw exceptions.
 
 I was able to get it working (in a small
prototype) by calling Springs ServletRequestListener manually from the
UIThread. (See code at the end of posting):
 The way I done it assumes the following
lifecycle between ServletRequest and UIThread, which I'm not sure is always
correct  ?
         -
createUI is always called from UIThread while the first ServletRequest
of a Session is running.
         -
within display.readAndDispatch() the ServletRequest is not switching, but
the method is rather just dispatching all events the current request 
 issued
         -
when there is no event left readAndDispatch() returns false, one has to
call display.sleep() and the request is finished by sending back whatever
needs to be sent back to the browser
         -
display.sleep() returns when there is the next request from the browser,
so there are new events in the event-queue.
 
 Are these assumptions right ?
 What is happening, when I have an extra
thread to calculate things and this thread puts an event into the queue.
I suppose display.sleep() wakes up, but what request does a call to RWT.getRequest()
return ?
 
 Could you think of a better approach
?
 I also thought about using RWTLiveCycle.addPhaseListener()
and listening to the start and end of PhaseId.PROCESS_ACTION, but was not
sure, whether this would be a better approach.
 
 
 
         public
int
createUI() {
          
      RequestContextListener requestContextListener
= new
RequestContextListener();
          
      ServletRequestEvent servletRequestEvent =
fireSpringRequestScopeStarted(requestContextListener); 
 
 
          
      //
createUI and access Spring-Business-Beans
          
      //
[...]
          
      ServletContext context = RWT.getRequest().getSession().getServletContext();
          
      WebApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(context);
          
      //
[...]
 
 
          
      while
(!shell.isDisposed()) {
          
              if
(!display.readAndDispatch()) {
          
               
      fireSpringRequestScopeEnded(requestContextListener,
servletRequestEvent);
          
               
      display.sleep();
          
               
      servletRequestEvent = fireSpringRequestScopeStarted(requestContextListener); 
 
          
              }
          
      }
          
      return
0;
         }
 
         private
ServletRequestEvent fireSpringRequestScopeStarted(RequestContextListener
requestContextListener)
{
          
      ServletRequestEvent servletRequestEvent =
new
ServletRequestEvent(RWT.getRequest().getSession().getServletContext(),
RWT.getRequest());
          
      requestContextListener.requestInitialized(servletRequestEvent);
          
      return
servletRequestEvent;
         }
 
         private
void
fireSpringRequestScopeEnded(RequestContextListener requestContextListener,
ServletRequestEvent servletRequestEvent)
{
          
      requestContextListener.requestDestroyed(servletRequestEvent);
         }

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Re: Integrating Spring (session/request) scoped Beans into RAP [message #81582 is a reply to message #81565]

Sat, 05 April 2008 14:47

Stefan Hansel

Messages: 103
Registered: July 2009

Senior Member

This is how a PhaseListener-solution
looks like (see below).
 This works equally well in my small
prototype and seems to be far more elegant.
 
 There's just one problem - where should
the PhaseListener be registered ?
 
 When using web.xml, two other important
PhaseListeners don't get registered and RAP is not working anymore. Our
web.xml thus has the following entry, but I think that this isn't safe
when new RAP versions come out.:
 
         <context-param>
          
      <param-name>org.eclipse.rwt.phaseListeners</param-name>
          
      <param-value> org.eclipse.rwt.internal.lifecycle.CurrentPhase$Listener,org .eclipse.rwt.internal.lifecycle.PreserveWidgetsPhaseListener ,de.tolina.web.SpringIntegratingPhaseListener </param-value>
         </context-param>
 
 Any suggestions whereelse our PhaseListener
could be registered ? IEntryPoint.createUI is not working, because the
PhaseListener then would be registered more than once.
 
 Here's the PhaseListener: 
 
 public
class
SpringIntegratingPhaseListener implements
PhaseListener {
         //
Springs RequestContextListener, where we will do fake calls for each PROCESS_ACTION

         private
final
RequestContextListener requestContextListener
= new
RequestContextListener();
 
         public
void
afterPhase(PhaseEvent event)
{
          
      ServletRequestEvent servletRequestEvent =
new
ServletRequestEvent(RWT.getRequest().getSession().getServletContext(),
RWT.getRequest());
          
      requestContextListener.requestDestroyed(servletRequestEvent);
         }
 
         public
void
beforePhase(PhaseEvent event)
{
          
      ServletRequestEvent servletRequestEvent =
new
ServletRequestEvent(RWT.getRequest().getSession().getServletContext(),
RWT.getRequest());
          
      requestContextListener.requestInitialized(servletRequestEvent);
         }
 
         public
PhaseId getPhaseId() {
          
      return
PhaseId.PROCESS_ACTION;
         }
 }

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Re: Integration Spring (session/request) scoped Beans into RAP [message #81693 is a reply to message #81582]

Mon, 07 April 2008 07:10

Eclipse User

Originally posted by: fappel.innoopract.com

This is a multi-part message in MIME format.

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Content-Type: text/plain;
charset="US-ASCII"
Content-Transfer-Encoding: 7bit

Hi,

your assumption about the readAndDispatch loop in your first mail are
correct. It's also correct how you've registered the phaselisteners for
RWT standalone - in case of manually configuring the phaselisteners like
you do the RWT listeners must be noted also. Don't know whether this is
the best solution, but that's how it works at the moment and in terms of
beeing API stable I don't expect this to be changed in the near future.

Ciao
Frank

_____

Von: stefan.hansel@tolina.de [mailto:stefan.hansel@tolina.de]
Bereitgestellt: Samstag, 5. April 2008 16:47
Bereitgestellt in: eclipse.technology.rap
Unterhaltung: Integration Spring (session/request) scoped Beans into RAP
Betreff: Re: Integrating Spring (session/request) scoped Beans into RAP

This is how a PhaseListener-solution looks like (see below).
This works equally well in my small prototype and seems to be far more
elegant.

There's just one problem - where should the PhaseListener be registered
?

When using web.xml, two other important PhaseListeners don't get
registered and RAP is not working anymore. Our web.xml thus has the
following entry, but I think that this isn't safe when new RAP versions
come out.:

<context-param>
<param-name>org.eclipse.rwt.phaseListeners</param-name>

<param-value>org.eclipse.rwt.internal.lifecycle.CurrentPhase$Listener,or
g.eclipse.rwt.internal.lifecycle.PreserveWidgetsPhaseListene r,de.tolina.
web.SpringIntegratingPhaseListener</param-value>
</context-param>

Any suggestions whereelse our PhaseListener could be registered ?
IEntryPoint.createUI is not working, because the PhaseListener then
would be registered more than once.

Here's the PhaseListener:

public class SpringIntegratingPhaseListener implements PhaseListener {
// Springs RequestContextListener, where we will do fake calls
for each PROCESS_ACTION
private final RequestContextListener requestContextListener =
new RequestContextListener();

public void afterPhase(PhaseEvent event) {
ServletRequestEvent servletRequestEvent = new
ServletRequestEvent(RWT.getRequest().getSession().getServlet Context(),
RWT.getRequest());

requestContextListener.requestDestroyed(servletRequestEvent) ;
}

public void beforePhase(PhaseEvent event) {
ServletRequestEvent servletRequestEvent = new
ServletRequestEvent(RWT.getRequest().getSession().getServlet Context(),
RWT.getRequest());

requestContextListener.requestInitialized(servletRequestEven t);
}

public PhaseId getPhaseId() {
return PhaseId.PROCESS_ACTION;
}
}

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charset="US-ASCII"
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Dus-ascii" =
http-equiv=3DContent-Type>
<META name=3DGENERATOR content=3D"MSHTML 6.00.6001.17184"></HEAD>
<BODY>
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008>Hi,</DIV>
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008> </DIV >
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008>your assumption about the readAndDispatch =
loop in your=20
first mail are correct. It's also correct how you've registered the=20
phaselisteners for RWT standalone - in case of manually configuring the=20
phaselisteners like you do the RWT listeners must be noted also. Don't =
know=20
whether this is the best solution, but that's how it works at the moment =
and in=20
terms of beeing API stable I don't expect this to be changed in the near =

future.</DIV>
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008> </DIV >
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008> </DIV >
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008>Ciao</DIV>
<DIV dir=3Dltr align=3Dleft><SPAN=20
class=3D125580407-07042008>Frank</DIV> 
<DIV dir=3Dltr lang=3Dde class=3DOutlookMessageHeader align=3Dleft>
<HR tabIndex=3D-1>
Von: stefan.hansel@tolina.de=20
[mailto:stefan.hansel@tolina.de] Bereitgestellt: Samstag, 5. =
April=20
2008 16:47 Bereitgestellt in:=20
eclipse.technology.rap Unterhaltung: Integration Spring=20
(session/request) scoped Beans into RAP Betreff: Re: =
Integrating=20
Spring (session/request) scoped Beans into =
RAP </DIV> <FONT=20
size=3D2 face=3Dsans-serif>This is how a PhaseListener-solution looks =
like (see=20
below). This works equally =
well in my=20
small prototype and seems to be far more elegant. There's just one problem - where should the =
PhaseListener be=20
registered ? When using =
web.xml, two=20
other important PhaseListeners don't get registered and RAP is not =
working=20
anymore. Our web.xml thus has the following entry, but I think that this =
isn't=20
safe when new RAP versions come out.:         <context-param>    =20
            <param-name>org.eclipse.rwt.phaseListeners</param-name>    =20
            <param-value> org.eclipse.rwt.internal.lifecycle.CurrentPhase$Listener,org .eclipse=
..rwt.internal.lifecycle.PreserveWidgetsPhaseListener,de.tol ina.web.Spring=
IntegratingPhaseListener<FONT=20
color=3D#008080 size=3D2 face=3D"Courier New"></param-value>    =20
    </context-param> Any=20
suggestions whereelse our PhaseListener could be registered ?=20
IEntryPoint.createUI is not working, because the PhaseListener then =
would be=20
registered more than once. Here's=20
the PhaseListener: public=20
class<FONT=20
size=3D2 face=3D"Courier New"> SpringIntegratingPhaseListener =
<FONT=20
color=3D#820040 size=3D2 face=3D"Courier =
New">implements PhaseListener {         // Springs RequestContextListener, where we will =
do fake=20
calls for each PROCESS_ACTION         private=20
final<FONT=20
size=3D2 face=3D"Courier New"> RequestContextListener requestContextListener =3D new=20
RequestContextListener();         public=20
void<FONT=20
size=3D2 face=3D"Courier New"> afterPhase(PhaseEvent event) {    =20
            ServletRequestEvent=20
servletRequestEvent =3D new=20
ServletRequestEvent(RWT.getRequest().getSession().getServletContext(),=20
RWT.getRequest());  =20
              requestContextListener.requestDestroyed(servletRequestEvent);=20
         =
}=20
         =
<FONT=20
color=3D#820040 size=3D2 face=3D"Courier New">public void=20
beforePhase(PhaseEvent event) =
{=20
         =
   =20
    ServletRequestEvent servletRequestEvent =3D <FONT=20
color=3D#820040 size=3D2 face=3D"Courier New">new=20
ServletRequestEvent(RWT.getRequest().getSession().getServletContext(),=20
RWT.getRequest());  =20
              requestContextListener.requestInitialized(servletRequestEvent);=20
         =
}=20
         =
<FONT=20
color=3D#820040 size=3D2 face=3D"Courier New">public PhaseId getPhaseId() {               =
 =20
return<FONT=20
size=3D2 face=3D"Courier New"> PhaseId.PROCESS_ACTION;         } } </BODY></HTML>

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