Return-Path: 
 <user-return-24853-apmail-commons-user-archive=commons.apache.org@commons.apache.org>
Delivered-To: apmail-commons-user-archive@www.apache.org
Received: (qmail 45325 invoked from network); 11 Aug 2010 21:05:10 -0000
Received: from unknown (HELO mail.apache.org) (140.211.11.3)
  by 140.211.11.9 with SMTP; 11 Aug 2010 21:05:10 -0000
Received: (qmail 56530 invoked by uid 500); 11 Aug 2010 21:05:09 -0000
Delivered-To: apmail-commons-user-archive@commons.apache.org
Received: (qmail 56453 invoked by uid 500); 11 Aug 2010 21:05:08 -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 56443 invoked by uid 99); 11 Aug 2010 21:05:08 -0000
Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136)
    by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 11 Aug 2010 21:05:08 +0000
X-ASF-Spam-Status: No, hits=0.0 required=10.0
	tests=FREEMAIL_FROM,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; Wed, 11 Aug 2010 21:05:03 +0000
Received: by wyb29 with SMTP id 29so550565wyb.30
        for <user@commons.apache.org>; Wed, 11 Aug 2010 14:04:42 -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
         :content-transfer-encoding;
        bh=luagFSxtl/qE81ajt4GozeY71G/WooAKqdFtQiivUxQ=;
        b=jbJWRAOCethzny+qqB4JbVBiKQZ64r9/oqjY18pOJYHJtUlLStQxd+f+V5KPbUQiIU
         5IR37hVKY7GUftcTaCRxfjaTTBRwlPJ1crwmmW4e8Z4LSeTt+URTVsN37byk47uJBA8w
         imKaAwyLGVgYEtEa8KC7+i2CCDkGdzObSKmDY=
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:content-transfer-encoding;
        b=tLiNFztMtkusqIEKvGY82hRKtxNMN1qNOJVnEzNrfiROnL6FDEC1gJT2jQQWP8Tdkh
         n41j6NBgBBMBX6Z9y0Ag6ePqB+XmJL0WZ+NWj03bVTZe1YLmo/XGcoyiPdrOQBVgbk5i
         zCLul6aONwluGd8luKzRddZCI957+DEm+4DZw=
MIME-Version: 1.0
Received: by 10.227.69.134 with SMTP id z6mr16874127wbi.201.1281560681752;
	Wed, 11 Aug 2010 14:04:41 -0700 (PDT)
Received: by 10.227.155.195 with HTTP; Wed, 11 Aug 2010 14:04:41 -0700 (PDT)
In-Reply-To: <4C62FF4E.3030800@mitre.org>
References: <4C61DCBE.8020400@mitre.org>
	<AANLkTik1rw5Zci+vomaVPDWmij32zxbS05qCMWp5OMDN@mail.gmail.com>
	<4C62E9B9.8000007@mitre.org>
	<AANLkTimoQhLM1n8ZrFQO0xK9nfpXebj_0PBGtGcg835=@mail.gmail.com>
	<4C62FF4E.3030800@mitre.org>
Date: Wed, 11 Aug 2010 17:04:41 -0400
Message-ID: <AANLkTi=zEs44CrcBEPwXJRU9v93baOmkM3SKtwGszPUW@mail.gmail.com>
Subject: Re: [scxml] datamodel, custom actions and digester
From: Rahul Akolkar <rahul.akolkar@gmail.com>
To: Commons Users List <user@commons.apache.org>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

On Wed, Aug 11, 2010 at 3:51 PM, Abigail Gertner <gertner@mitre.org> wrote:
>
>
> On 8/11/2010 3:36 PM, Rahul Akolkar wrote:
>> On Wed, Aug 11, 2010 at 2:19 PM, Abigail Gertner <gertner@mitre.org> wro=
te:
>>
>>>
>>> On 8/11/2010 12:29 AM, Rahul Akolkar wrote:
>>>
>>>> <snip/>
>>>> The way to obtain the live values of the datamodel is to use the
>>>> expression evaluator, see interfaces mentioned here:
>>>>
>>>> =A0 http://commons.apache.org/scxml/guide/contexts-evaluators.html
>>>>
>>>>
>>>>
>>> Is it possible to call a method using the expression evaluator with an
>>> argument that is a node in the XML tree, rather than just a string valu=
e?
>>>
>>>
>> <snip/>
>>
>> Executable content is open ended in SCXML, as largely speaking most
>> things are possible with custom actions. I'm afraid I've lost the
>> bigger picture of your scenario in the pin-pointed question above.
>>
>> To obtain a node using the expression evaluator, use
>> Evaluator#evalLocation(...) which returns a Node.
>>
>
> What I mean is, if I want to do something like:
>
> <onentry>
> =A0<cs:var name=3D"result" expr=3D"foo.bar(...)"/>
> </onentry>
>
> Where the argument to foo.bar() is a Node from the datamodel, but with
> the current context values included, how can I get that from the
> expression evaluator. I tried using the Data('var','path') expression
> but it doesn't seem to work for nodes.
>
<snip/>

Here are some ways to tackle this:

 * Break the above into smaller operations: (1) obtain a node, (2)
invoke the method. For example:

    <onentry>
      <my:node name=3D"arg" expr=3D"..."/>
  =A0   <cs:var name=3D"result" expr=3D"foo.bar(arg)"/>
    </onentry>

  where <my:node> uses Evaluator#evalLocation(...) and creates a "var"
matching the name argument.

 * Use XPath as the expression language as its better equipped to deal
with XML nodes. The above would then become:

   <onentry>
 =A0   <cs:var name=3D"result" expr=3D"foo:bar($dataid/xpath/to/node)"/>
   </onentry>

   However, the XPath evaluator isn't available in the latest release
however, but rather in a branch:

   http://svn.apache.org/repos/asf/commons/proper/scxml/branches/J6/src/mai=
n/java/org/apache/commons/scxml/env/xpath/

 * A bit of background - The Data() function is mostly limited to
values of leaf nodes (strings, integers) and is designed to satisfy
the rvalue of most assignment expressions. There is a corresponding
LData() -- I presume you're using JEXL -- that is meant to satisfy the
lvalue (and will return nodes) but these are implementation details so
resorting to using LData isn't recommended.


>>>> Might be worthwhile revisiting the need for using
>>>> SCXMLParser#newInstance() rather than the static parse methods.
>>>>
>>>>
>>>>
>>>>
>>> The reason I am doing this is that I am using xinclude to include a
>>> separate xml file and I found that I needed to call setXIncludeAware()
>>> on the parser to make it do the include. Is there some way to do this
>>> using the static parse methods?
>>>
>>>
>> <snap/>
>>
>> Not in the latest release (v0.9) so thats one of the cases where you
>> may indeed not be able to use the static parse methods. Based on what
>> I've read so far, it seems your best bet may be to register the
>> digester rules for your custom actions by hand after you obtain the
>> new instance and let the custom action do the appropriate expression
>> evaluation and datamodel / context processing.
>>
> I'm trying to do it this way now and having trouble getting the custom
> action to fire. I am using
>
> dig.addObjectCreate("!*/onentry/sendMessage", SendMessage.class);
>
> Where my custom action is called SendMessage.
>
> Then in my scxml file I have
>
> <onentry>
> =A0<sendMessage/>
> </onentry>
>
> The SendMessage object is being created when the file is parsed, but the
> execute() method is not being called when the state is entered.
> Do I have to do something else to get it to call execute()?
>
<snap/>

Minimally, you'll have to add the SetNextRule (and maybe others, as
per your action needs), so this:

  dig.addSetNext("!*/onentry/sendMessage", "addAction");

Also, best to use a different XML namespace for custom actions. See
Digester#setRuleNamespaceURI(...) for this purpose.

-Rahul

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