|Michael Shenfield||Nov 5, 2003 1:42 pm|
|Keith Swenson||Nov 5, 2003 3:49 pm|
|John Fuller||Nov 5, 2003 4:06 pm|
|Mayilraj Krishnan||Nov 5, 2003 5:18 pm|
|Keith Swenson||Nov 5, 2003 5:57 pm|
|Keith Swenson||Nov 5, 2003 7:14 pm|
|Michael Shenfield||Nov 6, 2003 8:12 am|
|Keith Swenson||Nov 7, 2003 6:45 am|
|Michael Shenfield||Nov 7, 2003 7:08 am|
|Keith Swenson||Nov 7, 2003 8:32 am|
|Michael Shenfield||Nov 7, 2003 8:44 am|
|David RR Webber||Nov 7, 2003 9:24 am|
|Mayilraj Krishnan||Nov 7, 2003 9:43 am|
|Keith Swenson||Nov 7, 2003 10:52 am|
|Jeffrey Ricker||Nov 7, 2003 11:08 am|
|Michael Shenfield||Nov 7, 2003 12:50 pm|
|Michael Shenfield||Nov 7, 2003 12:57 pm|
|David RR Webber||Nov 7, 2003 2:24 pm|
|Keith Swenson||Nov 9, 2003 9:59 am|
|Subject:||Re: [asap] Factory in ASAP|
|From:||David RR Webber (dav...@drrw.info)|
|Date:||Nov 7, 2003 2:24:50 pm|
Title: RE: [asap] Factory in ASAP
That's all reasonable too. But from time to time you hit across stuff that is debatable. Then you have to make a decision to either include it now, or defer it until later, or duck it.
If your goal is to get a published spec' out ASAP - then you want to restrict what you are taking on board. But often you hit usage cases that need to be address to ensure the specification is robust and sufficient in its first release. If such extras can be address cheaply in terms of effort and syntax, and minimal side-effects - its usually an easy call to go for it.
It's a judgement call for the team then to make. I'd say you are still relatively early in the process here so its good to address these things now. Obviously if someone raises something 2 weeks before you are going out to public vote on a spec' - then that's an easy "V2.0" call!
----- Original Message -----
From: Keith Swenson To: 'David RR Webber' ; Michael Shenfield ; Keith Swenson ; Mayilraj Krishnan ; Jeffrey Ricker Cc: ASAP Sent: Friday, November 07, 2003 1:56 PM Subject: RE: [asap] Factory in ASAP But what is the charter if it is not the definition of the group? The purpose of the charter is to define what is and is not suitable for discussion in this forum. If we don't adher to the charter, then we risk losing focus, and risk failing to produce anything at all. The people that signed up for the group did so on a basis of what the charter said.
It is understandable that someone may have joined the group without understanding completely the charter. To me, the essense of what distinguishes an asynchronous service from other is the ability to monitor and control it. It is not simply a normal service that takes a long time. It is a service that might take long enough that you might change your mind and cancel it. Without the ability to monitor and cancel, we are not solving the problem defined by the charter. I am open to discussion on this, but to me it is pretty clear.
Michael is not interested in this. He instead is interested in services that are wireless friendly. This is an interesting and important topic, but this is not the "Wireless Friendly Service Protocol" technical comittee. I deeply regret discouraging his input, because he has provided the best input so far in the group, and he clearly is knowledgeable in his field. But in order to fair to everyone who has signed up for this group, I feel I must try to keep the discussion focussed on the subject defined by the charter.
If someone wants to change the charter, then please take that discussion into a subcommittee and off the main list. Then propose the new charter to the group and put it to the vote. Until that time, I want to focus on the problem defined by the current charter.
-----Original Message----- From: David RR Webber [mailto:dav...@drrw.info] Sent: Friday, November 07, 2003 9:29 AM To: Michael Shenfield; Keith Swenson; Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: Re: [asap] Factory in ASAP
Actually that's not at all so! The Charter is NOT set in stone. You can change it - there is a process for doing that - see the OASIS manual for that detail.
However - perhaps a better solution here is to have a subcommittee. The subcommittee can go off and research "stuff" and then come back and recommend something to the main TC.
So - for instance - you could have a SC to investigate if the charter needs to be extended, if that would be appropriate to do, and if it makes sense for the TC to do it as an extension of their original focus.
To setup a TC you need to have a vote at your next meeting - and then agree on what the terms of reference are for the SC, then notify Jamie at OASIS - he sets up the SC area in Kavi - and then members can signup there and participate, etc.
Hope this helps.
----- Original Message ----- From: Michael Shenfield To: Keith Swenson ; Mayilraj Krishnan ; Jeffrey Ricker Cc: ASAP Sent: Friday, November 07, 2003 11:49 AM Subject: RE: [asap] Factory in ASAP Well...if what you say about the charter is correct and it's "carved in stone" than all discussions about the scope are obsolete as it's predefined. In this case I just retreat to observer status. I am not very interested in "monitored and controlled" asynchronous services as they are not wireless friendly by nature. -----Original Message----- From: Keith Swenson [mailto:KSwe...@fsw.fujitsu.com] Sent: November 7, 2003 11:37 AM To: Michael Shenfield; Keith Swenson; Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: RE: [asap] Factory in ASAP
The charter of this technical committee specifically states that the asynchronous service is something that that can be monitored and controlled. This charter was put into place to guide our discussion, and to keep us from getting off track. Since you agree that a factory is needed to be able to monitor and control an asynchronous service, then any discussion about alternate approaches should be taken to a different technical committee.
Please understand, it is not that I don't respect your position, or that I think the problem you are tyring to solve is unimportant. It is only that this technical committee is set out to solve is the problem defined by the charter. This technical committee CAN NOT change the charter. In order to accomplish that goal, we need to remain very much focussed on what the charter says.
If you disagree with the charter, then make a new charter and technical committee. It is not hard.
That being said, this technical committee MUST have a protocol that allows for the monitoring and controlling of an asynchronous service. There may be ways that involve somthing other than a factory, and I am open to discussions about this.
It is possible that a particular IMPLEMENTATION of the protocol "degrades" such that it instead of being monitorable and controllable, it returns an error message instead. I am not saying that all asynchronous services must be controllable or monitorable. But, the protocol MUST provide for this capability.
The 80/20 rule works as long as you meet fundamental criteria. For example, a car is not a car if it has no wheels. The 20% that remains must include some sort wheels. The fundamental criteria in this case is that a service can be monitored and controlled.
-----Original Message----- From: Michael Shenfield [mailto:mshe...@rim.net] Sent: Friday, November 07, 2003 7:13 AM To: 'Keith Swenson'; Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: RE: [asap] Factory in ASAP
Re: "...Let me repeat my request from before: Describe what must be done to link two systems at run time together such that one can start a long term process, update it later, check its status, and terminate it if necessary. It is from the dynamics of this linking that the advantages of this approach appear..."
Sure, if you want to do all these things (update, check status, terminate) you'll need a factory. Following 80-20 rule I would assume that only 20% of async service implementations ever need these features, therefore I am quite convinced that it would be an overkill to include it in the spec as a requirement for ASAP compliance. As we represent two poles in the view on the scope of specification we need to let the rest of the group to express their opinion, hopefully we will get a features list from Jeffrey anytime soon and be able to vote on specific features to be included/excluded. Essentially it should solve an argument about the need for a factory. Cheers,
-----Original Message----- From: Keith Swenson [mailto:KSwe...@fsw.fujitsu.com] Sent: November 7, 2003 9:50 AM To: Michael Shenfield; Keith Swenson; Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: RE: [asap] Factory in ASAP
>> Your other example is with 1,200,000,000 operations. Again I am puzzled. >> Why not to have just 4 operations Create, CheckStatus, Change, and Cancel
>> while passing an SSN as a parameter(part)? Of course, in this case it would probably be better to do what you suggest. The example was bad, but all I was using it for was to show that factories can be "virtual". A better example might be that the factory address includes the name of a Java class which is a servlet to be invokved. Or it even could specify the method on a particular class. The point is that there does not need to be any additional overhead just because there are a number of "factories". >> I think the mechanism of Web Service instantiation >> should be left to framework providers. Of course it should. Please don't confuse the creation of a web service with the creation of an Asynchronous Service Instance. Creating an instance
of the service, is not really creating a new web service. Just like creating and instance of an object is not creating any new methods. >> We have prototype Web Services ... and nowhere had to worry about "factories" As I mentioned, there are an unlimited number of ways to do things. The need for factories comes only from wanting to link to systems that expect factories. You probably never did this. Let me repeat my request from before: Describe what must be done to link two systems at run time together such that one can start a long term process, update it later, check its status, and terminate it if necessary. It is from the dynamics of this linking that the advantages of this approach appear. (And think back to the beginning of the OO days when all the programmers were pointing out that any program can be written without using OO constructs. The difference lies not in the program, but in the ability to reuse it in many different situations.) -Keith Swenson P.S. We have some unfinished issue from an earlier conversion. I was hoping that someone else would chime in, but since they have not I will follow with a separate message. -----Original Message----- From: Michael Shenfield [mailto:mshe...@rim.net] Sent: Thursday, November 06, 2003 8:17 AM To: 'Keith Swenson'; Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: RE: [asap] Factory in ASAP
Wow...that's a long email. I had a hard time reading it on my Blackberry at breakfast :) Now to the point. I don't think anybody argues the importance of "Resource Oriented" approach, that's why people define multiple Web Services (and ports) instead of offering just one Web Service with a large number of operations. Your analogy with object-oriented vs. procedure-oriented? True...the concepts are related somehow. My question is what it all has to do with the Factories? Your example on car repairs only shows that one has to define two web services "CarRepairAppointment" and "AccessoryOrder". Your
other example is with 1,200,000,000 operations. Again I am puzzled. Why not to have just 4 operations Create, CheckStatus, Change, and Cancel while passing an SSN as a parameter(part)? And again what it has to do with the "Resource oriented" concept? Am I missing something here? Let me explain my position on Factory. I don't have any problems with somebody implementing the Factory as a web service, I just don't see the need for defining one in a standard. We have prototype Web Services implemented in .NET, WebLogic, SunONE, and WebSphere and nowhere had to worry about "factories" as Web Service access and instantiation is taken care by the framework. I think the mechanism of Web Service instantiation should be left to framework providers, it's non of the business of Web Service developer. The Web Service just have to be there for you when accessing the port. As for ASAP specific information it can be easily passed
in the header (my "yes" vote) or as a predefined operation (my "no" vote). I've been programming COM and EJB for years and was quite happy to see that Web Services got rid of programmer-aware "factory" concept, so I don't need to call coInitialize(Ex), coCreateInstance(Ex), etc. to get my COM interface
or to call EJBHome.create to get my EJBRemote. Why do we need to go back in time and define factory for ASAP? Could you find "factory" as a principal concept in any mainstream Web Services specification? I am not aware of any... Cheers, Mike
-----Original Message----- From: Keith Swenson [mailto:KSwe...@fsw.fujitsu.com] Sent: November 5, 2003 9:02 PM To: Michael Shenfield; Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: RE: [asap] Factory in ASAP
The factory concept is the central concept to this whole approach. Of course, there are an infinite variety of ways that one might approach a particular problem. This particular approach uses a small number of generic
"operations" on a large number of "resources". The meaning of the operation
depends on the address of the resource. This is the "Resource Oriented" approach. The other approach is an "Operation Oriented" approach. One should not be concerned about the multiplicity of the factories. The existance of a factory does not mean that it takes up resources on the host machine. The factory address can have data values encoded into it. I can, if I wish, claim that I have 300 Million factories, one for each person in the USA, by making the factory address have a SSN as a parameter (or any other disambiguating value) in the address. I don't have to make 300 million records ahead of time. There is, then, no reason to try to reduce the number of factories, nor is there any basis to equate a minimal number of factories to a minimal feature set. The WWW functions on this principle of a few operations on a large number of
addresses. For example, instead of using the web, you could define an operation to retrieve the basic page, then an operation to retrieve each graphic on the page, and another operation to retrieve the style sheet for the page, etc. Some people would claim that this is a "good" way to design the system because getting the style sheet you use an operation specifically
for getting the style sheet, and what you get back from this operation is always a style sheet. Hence, it is strongly typed. Instead, the web merely
makes the page, the graphics, and the style sheet have different addresses. The same GET operation can be used to get each one. Plus, I can remain confident that if the future brings a new data type that can be embedded in a page, the same GET operation can retrieve that data equally well. Some people will complain that to display a page you need to make a number of GET
operations instead of one. True. Those same people might argue that a single XYZ operation would be "simpler". This is NOT true, because the specific information about the XYZ function must be specified some way in order to get the basic linking accomplished. One problem, among many, is that servers and browsers need to be upgraded simultaneously in order to get
new capabilities. Simultaneous upgrade does not happen in the real internet
world. Back to ASAP: lets consider a real example. A car dealer has two asynchronous web services: one that people can use to make an appointment at
the garage to get their car repaired, and the other to order a particular accessory for a car. The reason I pick these examples is because they are things that have a "duration" -- they persist over time. There should be no
disagreement that for a customer to arrange for a repair appointment some data (expressed as XML) needs to be sent from the customer to the car dealer, and that for ordering a accessory a different set of data needs to be sent. This discussion then is really just over how to talk about how these two pieces of data are different. Some approaches will make the "operation name" be different between the two blocks of data. The ASAP approach makes the "address" be different. For this scenario, using an "Operation Oriented" approach, we could define operations for CreateCarRepairAppointment, and CreateAccessoryOrder. We would also need to define operations for CheckCarRepairAppointmentStatus, CancelCarRepairAppointment, ChangeCarRepairAppointment, CheckAccessoryOrderStatus, CancelAccessoryOrder, and ChangeAccessoryOrder. The instance is automagically created behind the scenes, the correlation is encoded somewhere in the data passed. Using the "Resource Oriented" approach, we say there is an address for "CarRepairAppointment" and a different address for the "AccessoryOrder". Specifically, these are the addresses of the factory. Knowing these addresses, we can call the generic CreateInstance operation. We get an instance address which has the correlation information encoded into it. We then can call the generic Cancel (actually Terminate), Check (actually Get),
and Change (actually Set) on the instance. As you can see there is a one to one mapping between these two approaches. The same number of actual messages is passed, the same amount of data must be stored. The reason for taking the "Resource Oriented" approach becomes more clear when you carefully consider what must be done in order to link two systems together. There are systems that are designed to be able to start remote asynchronous processes. They already know about the basic operations: Create, Get, Set, and Terminate. In order to link such a system to the remote service, you must give it the information to link. Using the resource oriented approach, you only need to give it the address of the Factory resource. On the other hand, using the "Operation Oriented" approach, you must first tell that system which operation is the create operation. You have to program this somehow. You must tell it which operation is to be used to cancel the remote service. Etc. Once you buy into the basic idea that actual operation is a combination of an address and a generic operation, there are some very cool things that can
be accomplished very easily: Imagine that company G build (through any means) a system that automatically call the AccessoryOrder operations. Company G is a trusted partner who brings a lot of business, so the car dealer implements a "Pre Approved Accessory Order" that handles the order in
an expedited manner. Simply by changing the address of the factory, all the
associated operations are changed congruently, and the system interacts with
the expedited process. For this discussion, I used a NamingConvention: CreateXXX, CheckXXXStatus, ChangeXXX, and CancelXXX. This might be an alternative way to get the same benefit. No such naming convention exists. The naming convention approach gets really nasty when you want to encode something like a SSN into the address. You would have 1,200,000,000 operations. We can easily communicate addresses of a factory, but communicating the names of the correct 4 operations from a field of 1.2 billion is somehow less comfortable. Of course you could hide this by having 300M virtual WSDL files (generating on demand of course so it does not take any space) but the
linking of operations is normally considered a design time activity. Most systems to call remote processes are not really designed to take a WSDL file
at run time, search out the operation necessary according to a naming convention, and then call that operation. It is messy if you want this kind
of flexibility. On the other hand, the "Resource Oriented" approach is designed for exactly this kind of flexibility. In summary, please think carefully about the "DYNAMICS" of linking systems at run time as is necessary in a real life internet environment where change
is constant, and the systems you are linking to are not under your control. -Keith -----Original Message----- From: Michael Shenfield [mailto:mshe...@rim.net] Sent: Wednesday, November 05, 2003 1:47 PM To: Mayilraj Krishnan; Jeffrey Ricker Cc: ASAP Subject: RE: [asap] Factory in ASAP
I already expressed my concerns about "Factory" concept. In all existing Web
Services platforms that I am aware of the "Factory" is invisible for the WS developer and non of her/his concern at the time of development and deployment. I think we should step back and define a minimal scope of ASAP (as agreed at the last two conference calls). I doubt "factory" should make it there. -----Original Message----- From: Mayilraj Krishnan [mailto:mkri...@cisco.com] Sent: November 5, 2003 3:32 PM To: Jeffrey Ricker; ASAP Subject: [asap] Factory in ASAP
So far I have been thinking we need just only one factory for ASAP implementation or the implementation of services could be conveniently placed under one logical ASAP factory. I have two web services one is check inventory, shipping. Why do I need to create two ASAP factory? I think the ASAP pattern is generic enough, it can just have one factory. [In terms of WSDL 1.2 we could map this to one ASAP (soap/transport protocol) binding and one feature)] Is that a right assumption? Thanks Mayilraj At 11:35 AM 11/4/2003 -0500, Jeffrey Ricker wrote: >I have attached files for describing the current draft of ASAP in WSDL. >These are rough draft documents that have not been proofed. > >The asap.xsd describes the payloads >The asap.wsdl is the basis for all ASAP services > >The concept here is to treat ASAP as a binding. The message structures >are all the same, the programmer only has to define the ContextData and >the ResultsData elements. > >The checkInventory.wsdl and productLevel.xsd files provide an example of >this ASAP-as-a-binding approach. > >Ricker > > > > >To unsubscribe from this mailing list (and be removed from the roster of >the OASIS TC), go to >http://www.oasis-open.org/apps/org/workgroup/asap/members/leave_workgroup.p
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