RE: [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda for Tuesday 11June

From
Filon Qeshef
Date
2002-06-11T19:37:39+00:00
ID
007901c2117f$6a0338b0$ea0aa8c0@eilon
Thread
RE: [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda for Tuesday 11June
Title: Message

Alan,

 

Comments below, with <ER>

 

I'll follow up with a related question in a subsequent 
e-mail

 

Eilon

 

-----Original Message-----
From: Alan 
Kropp [mailto:] 
Sent: Tuesday, June 11, 2002 
3:05 PM
To: 'Eilon Reshef'; Alan Kropp; ; 

Subject: RE: [wsrp] [wsia] [wsrp-wsia joint 
interfaces] agenda for Tuesday 11 June

  
Hi 
  Eilon,

  
 

  
It 
  seems to me the Consumer still doesn't really need a say in how the Producer 
  implements the search service runtime model.  It's true that if the 
  Producer creates all of these transient entities, there is the issue of when 
  it is "safe" to destroy them.  Transient entities don't have an 
  inherent lifecycle, but the sessions which talk to them do...so, when 
  these sessions have timed out, the Producer is able to determine that a 
  transient entity is no longer a party to any active session.  Would 
  it be valid to say that the Producer, at that point, may assume the 
  transient entity is stale and destroy it?   

  
 

  
<ER> I 
  would think so </ER>

  
 

  
 I guess this is a variation 
  on reference counting/GC that Java developers are already familiar with. 

  
 

  
<ER> 
  yes, except that reference counting is possible in a closed environment, 
  whereas "guesswork" (i.e., timeouts ;-) is the option that will be used in 
  practice </ER>

  
 

  
I don't think it's unrealistic to expect the Producer to employ 
  intelligence like this to efficiently manage its entities. 

  
 

  
<ER> I 
  would assume that transient entities would be implemented as or within 
  sessions, as you suggested so this would be taken care by the infrastructure 
  </ER> 

  
 

  
Alan

  
 

  
 

  
    
-----Original Message-----
From: Eilon Reshef 
    [mailto:]
Sent: Tuesday, June 11, 2002 
    11:36 AM
To: 'Alan Kropp'; ; 
    
Subject: RE: [wsrp] [wsia] [wsrp-wsia 
    joint interfaces] agenda for Tuesday 11 June

    
Alan,

    
 

    
I think that one example scenario is a search results page, say for 
    hotels, that dynamically displays multiple maps - a map for each hotel 
    found. 

    
 

    
Assuming that maps are remote services, and assuming that the number 
    of results is dynamic, the Consumer needs to create multiple copies of the 
    map service. If we allow the Producer to determine the persistence state of 
    those maps, that would mean that someone will have to take care of the 
    lifetime of those maps. The Consumer can't, because the page may be gone 
    without the Consumer never knowing about it (the user closes the browser 
    window). The Producer can't, because it can't tell whether the Consumer has 
    stored a reference to those maps as part of a design-time description of a 
    user page.

    
 

    
Is that along the lines of what you were looking 
    for?

    
 

    
Eilon

    
      

      
-----Original Message-----
From: Alan Kropp 
      [mailto:] 
Sent: Tuesday, June 11, 2002 
      2:18 PM
To: ''; 
      ''
Subject: RE: [wsrp] [wsia] 
      [wsrp-wsia joint interfaces] agenda for Tuesday 11 
      June

      
I find that the question of a Consumer creating a 
      persistent vs. a transient 
entity to be a little 
      troubling. 

      
Isn't the Consumer primarily interested in getting a 
      handle to an _entity_ 
(be that transient or 
      persistent), and then using that handle to direct 
subsequent requests to? 

      
Could we not consider persistence and transience to be 
      entirely Producer 
concerns?  I understand 
      from the sequence in the spec (pp. 6-8) that the 
only supporting scenario for the Consumer calling 
      "createTransientEntity" is 
out of an effort to 
      maximize the efficiency of the conversation with the 
Producer.  This is a worthy goal, of course, but the Producer 
      should 
advertise its interaction behavior in the 
      meta-data, right?  Presumably the 
Producer 
      uses the meta-data to hint to the Consumer the way(s) the Consumer 
      
SHOULD structure invocation requests efficiently. 
      

      
I'd love to see some more convincing scenarios to support 
      pushing the 
persistent/transient aspect of the 
      conversation out to the Consumer. 
Otherwise, I'd 
      love even more to limit our specification to a single 
"createEntity" call. 

      
Alan 

      
-----Original Message----- 
From: 
      Carsten Leue [mailto:] 
      
Sent: Tuesday, June 11, 2002 2:19 AM 
To: Gil Tayar 
Cc: thomas klein6; 
      ''; 
'' 
Subject: RE: 
      [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda for 
Tuesday 11 June 

      
Gil - 

      
1-3: the consumer MUST explicitly create entities 
      (transient or 
persistent). It can decide to create 
      sessions explicitly if it wants to 
share them 
      amongs entities, otherwise it can let the producer create 
sessions on the fly. 
4: the decision to 
      have multiple entities per session is up to the consumer 
who make this choice based on the producer's metadata. e.g think 
      of 
portlets that form a shop together. These would 
      want to share a session 
with each other. But the 
      consumer could decide to have two shops of the 
same type on the same page. Then there would be two sessions and 
      only the 
consumer could know what portlet shares 
      what session. 
5: The consumer should create a 
      session before issuing a getFragment call. 
The 
      entity is created whenever necessary. 
6: A Session 
      is a bucket that holds some data (physically on the provider) 
      
and times-out after a while. A transient entity is a 
      remote portlet that 
does not store any data in a 
      DB. 

      
Hope that helped. 

      
Best regards 
Carsten Leue 
      

      
------- 
Dr. Carsten Leue 
      
Dept.8288, IBM Laboratory B鐽lingen , Germany 
      
Tel.: +49-7031-16-4603, Fax: +49-7031-16-4401 
      

      
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<>, Thomas| 
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      Klein6/Germany/IBM@IBMDE 
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  |       Subject:  RE: 
      [wsrp] [wsia] [wsrp-wsia joint interfaces] agenda 
for Tuesday        11 
      June                                            
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Carsten, could you clarify some things for me? 

      
1. If sessions and entities are orthogonal, what SHOULD 
      the Consumer do? 
2. SHOULD it create a transient 
      entity _and_ a session? 
3. MUST it do so? 
      
4. Who gets to decide whether there are multiple entities 
      per session or 
multiple sessions per 
      entities? 
5. When SHOULD a Consumer create a 
      session and when a transient entity? 
6. What _is_ 
      a session, logically? What _is_ a transient entity? 

      
Gil 

      
-----Original Message----- 
From: 
      Carsten Leue [mailto:] 
      
Sent: Tuesday, June 11, 2002 08:45 
To: Alan Kropp 
Cc: 
      ''; ''; thomas 
      
klein6 
Subject: Re: [wsrp] [wsia] 
      [wsrp-wsia joint interfaces] agenda for 
Tuesday 11 
      June 

      
Alan - some first thoughts 

      
1. the general concept is that entities (transient or 
      persistent) and 
sessions are orthogonal. There 
      might be mulitple entities per session and 
(at 
      least for persistent entities) multiple sessions per entity. An 
      example 
for the first case would be that entities 
      share session data within  the 
same user 
      request. An example for the second case are portlets on a common 
      
page (group page) that are access simultaneously by 
      multiple users. 
A transient entity differs from a 
      persistent entity in that its data does 
not 
      persist and its lifecycle is coupled with the session life cycle. 
      

      
2. Eilon pointed out in a comment to the interface 
      proposal that batch 
processing is already part of 
      SOAP. I was not aware of that and will look 
it up 
      until the call. 

      
Best regards 
Carsten Leue 
      

      
------- 
Dr. Carsten Leue 
      
Dept.8288, IBM Laboratory B鐽lingen , Germany 
      
Tel.: +49-7031-16-4603, Fax: +49-7031-16-4401 
      

      
|---------+----------------------------> 
      
|         
      |           Alan 
      Kropp       | 
|         
      |           
      <akropp@epicentri| 
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      |           
      c.com>           
      | 
|         
      |                            
      | 
|         
      |           06/11/2002 
      01:54 | 
|         
      |           
      AM               
      | 
|         
      |           Please 
      respond to| 
|         
      |           Alan 
      Kropp       | 
|         
      |                            
      | 
|---------+----------------------------> 

      
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<>        
      | 
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      cc: 
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      |       Subject:  [wsrp] [wsia] 
      [wsrp-wsia joint interfaces] agenda for 
Tuesday 
      11  
      June                                                      
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I think we'll have plenty of discussion around the merged 
      document Rich and 
Carsten put together. 

      
The two main issues I see that have arisen on the email 
      lists are: 

      
1.  What is the difference between transient entities 
      and sessions, and is 
there enough of a distinction 
      to warrant including both in the 
specification? 

      
2.  There are efficiency concerns around the use of 
      arrays in the method 
signatures, basically to 
      enable batched requests for network efficiency. 

      
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Alan 

      
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