Return-Path: 
 <user-return-24930-apmail-commons-user-archive=commons.apache.org@commons.apache.org>
Delivered-To: apmail-commons-user-archive@www.apache.org
Received: (qmail 14547 invoked from network); 4 Sep 2010 17:44:46 -0000
Received: from unknown (HELO mail.apache.org) (140.211.11.3)
  by 140.211.11.9 with SMTP; 4 Sep 2010 17:44:46 -0000
Received: (qmail 87988 invoked by uid 500); 4 Sep 2010 17:44:45 -0000
Delivered-To: apmail-commons-user-archive@commons.apache.org
Received: (qmail 87874 invoked by uid 500); 4 Sep 2010 17:44:45 -0000
Mailing-List: contact user-help@commons.apache.org; run by ezmlm
Precedence: bulk
List-Help: <mailto:user-help@commons.apache.org>
List-Unsubscribe: <mailto:user-unsubscribe@commons.apache.org>
List-Post: <mailto:user@commons.apache.org>
List-Id: <user.commons.apache.org>
Reply-To: "Commons Users List" <user@commons.apache.org>
Delivered-To: mailing list user@commons.apache.org
Received: (qmail 87865 invoked by uid 99); 4 Sep 2010 17:44:45 -0000
Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136)
    by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 04 Sep 2010 17:44:45 +0000
X-ASF-Spam-Status: No, hits=0.0 required=10.0
	tests=FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS
X-Spam-Check-By: apache.org
Received-SPF: pass (athena.apache.org: domain of rahul.akolkar@gmail.com
 designates 74.125.82.171 as permitted sender)
Received: from [74.125.82.171] (HELO mail-wy0-f171.google.com) (74.125.82.171)
    by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 04 Sep 2010 17:44:38 +0000
Received: by wya21 with SMTP id 21so3223481wya.30
        for <user@commons.apache.org>; Sat, 04 Sep 2010 10:44:17 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=gamma;
        h=domainkey-signature:mime-version:received:received:in-reply-to
         :references:date:message-id:subject:from:to:content-type;
        bh=8O0tgzYWZNXVLvrBxBCZ140OrcCvrvtxgRnoydzWmZU=;
        b=YrHM2mbNYTi4zqWC03uwn5dPZ5Okf2ccCvc2PnyQEyROFEwGY66CFF6fKLyY0c3b+j
         WBJkgZzqm1tVH/Q/fluSnJzqQAb2dtaDznIvc1/43oSySntnqd7v56SPQ4n313oLinQe
         NjjaSfoLAsLG65hBhUngUbjEpkA3uGA8f1YKw=
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:in-reply-to:references:date:message-id:subject:from:to
         :content-type;
        b=YIrZeuu+ZFlnobO65ybrpSTCv9TM56cxp+vhREkhDIoWoxmK/trzFH+RfcdOLCD0PL
         it5jMxBxKRdb7/adYYdIijCUTITTS62ifVvASHVRlhvH+gj6uaBBPbDEBU+UKAjHsyGC
         PyUgB7kFbnfgcMhAuVwYJmLfxwjHxkcAKi34g=
MIME-Version: 1.0
Received: by 10.227.24.141 with SMTP id v13mr163089wbb.210.1283622256954; Sat,
 04 Sep 2010 10:44:16 -0700 (PDT)
Received: by 10.227.133.84 with HTTP; Sat, 4 Sep 2010 10:44:16 -0700 (PDT)
In-Reply-To: <AANLkTikWwOe+7Cme4g7p6x6yiOgv60RzH6X1hj0aGD=J@mail.gmail.com>
References: <AANLkTikQuS6SKTsUNN_R7=mdtB7RrvnqvzQbd_ZPqFw5@mail.gmail.com>
	<AANLkTim6WKzVkNUY5R8r5hOgVh2Doekjnk8Os-R-TWyK@mail.gmail.com>
	<AANLkTikWwOe+7Cme4g7p6x6yiOgv60RzH6X1hj0aGD=J@mail.gmail.com>
Date: Sat, 4 Sep 2010 13:44:16 -0400
Message-ID: <AANLkTi=BHetnqoWn2GQ6iPXksH96RMg_V3eVaDJzXecX@mail.gmail.com>
Subject: Re: [scxml] update datamodel from java
From: Rahul Akolkar <rahul.akolkar@gmail.com>
To: Commons Users List <user@commons.apache.org>
Content-Type: text/plain; charset=ISO-8859-1

On Sat, Sep 4, 2010 at 1:19 PM, Azraiyl <azraiyl@gmail.com> wrote:
> Thanks for your response. Just out of curiousity: Is this the intended
> behaviour of SCXML?
>
> Chapter 3.3.3: If the "event" clause is missing, the transition is
> taken whenever the "cond" evaluates to true.
>
<snip/>

At a high level, the only way for the environment to communicate with
a state machine is through events. Data model changes are best made
via native mechanisms described in state machine theory (such as event
payloads). Doing so will cause the "cond" to be evaluated in the
process and has the additional benefit of being more declarative (i.e.
it will be modeled with the rest of the state machine, rather than
behavior that can't be noticed just by reading the SCXML document).

Programmatic access to the data model (only root context is
accessible) is provided as this is often convenient in certain
environments. However, such access clearly isn't portable across
implementations and has the downsides of not being tied into the event
processing loop. If such a choice is made by the developer, there is
an additional onus on the developer -- this includes, firing an event
if need be and synchronizing access if needed etc.

IMO, the section 3.3.3 quote probably needs some sort of disclaimer
for programmatic access. There are cases where the application may
deem it unnecessary for every programmatic update to the root context
to result in evaluating all conds. Commons SCXML provides the
developer that level of control.

-Rahul

---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
For additional commands, e-mail: user-help@commons.apache.org