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Re: Resource definition

From: Francis McCabe <fgm@fla.fujitsu.com>
Date: Wed, 19 Feb 2003 08:55:34 -0800
Cc: "Burdett, David" <david.burdett@commerceone.com>, www-ws-arch@w3.org
To: Mark Baker <distobj@acm.org>
Message-Id: <F6BAFDC6-442A-11D7-BE02-000393A3327C@fla.fujitsu.com>


On Tuesday, February 18, 2003, at 05:33  PM, Mark Baker wrote:

>
> On Tue, Feb 18, 2003 at 04:38:54PM -0800, Burdett, David wrote:
>> In an earlier email, Francis McCabe said ...
>>
>>>>> ... to use one of Mark's earlier examples, turning on a light 
>>>>> switch. The
>> state of the light is a representable resource; no question. The 
>> action of
>> flipping the switch is not so representable. The arm which is used to 
>> flip
>> the switch is, however, a resource; although any representation of it 
>> in
>> terms of bits is merely a symbol and not the real thing.<<<
>>
>> So is the act of moving the arm to turn on/off the switch a resource?
>
> Well, I suppose you could make it one, but I'm not sure what that
> would accomplish.
>
> One doesn't need to talk about a switch, or the movement of a switch, 
> or
> even a toggleSwitch() method, in order to effect a state change with 
> the
> bulb, because the interaction style is one of *state transfer*; if I
> want to turn the bulb on, I just do a HTTP PUT containing a
> representation of the "on state" to the URI identifying the lightbulb.
>

This is NOT correct. (IMHO)

First of all, there are any number of actions which cannot be 
represented by an update in the state; especially in any state that is 
accessible to the requestor!

Secondly, simply telling the resource that the light is on is not 
equivalent to actually switching the switch!

Frank
Received on Wednesday, 19 February 2003 11:56:23 GMT

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