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Posted to users@cocoon.apache.org by Benoit Deshaies <bd...@yahoo.com> on 2004/06/03 20:46:19 UTC
CForm binding: creating objects?
Hi,
I was wondering what was the simplest way to use the Forms Binding
Framework to create new objects. I have the following Java model I
created a form for:
public class SightingReport {
private String birdName;
private GeoCoordinate latitude;
// gets/sets
}
public class GeoCoordinate {
private int deg;
private int min;
private int sec;
// gets/sets
}
SightingReport.latitude is initialized to null. My binding file looks
like this:
<fb:context path="/" >
<fb:value id="birdName" path="birdName"/>
<fb:value id="latDeg" path="latitude/deg"/>
<fb:value id="latMin" path="latitude/min"/>
<fb:value id="latSec" path="latitude/sec"/>
</fb:context>
When I invoke form.save(sightingReport), I get the following error:
Exception trying to create xpath latitude/deg; Factory is not set on
the JXPathContext - cannot create path: /latitude.
What would be The Best Way to initialize the latitude object (invoke
default constructor) ? <fb:javascript> ? <fb:custom> ?
Many thanks,
Benoit Deshaies
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Re: CForm binding: creating objects?
Posted by Marc Portier <mp...@outerthought.org>.
Benoit Deshaies wrote:
> Many thanks Marc. That's exactly what I was looking for. For some
> reason, I had assumed this was just to add an item to a Collection...
>
well, the reason might be the obvious directed examples which are
inspired from some original need and are thus likely to communicate some
'intention' (see also the reflection of that in the naming 'insert'
'addmethod')
all of those intentions however don't get in the way of just doing what
you need :-)
this basically comes from the fact that there is really nothing magic
about the binding: it is (just) a set of xml declarations that quite
unmagically map onto executed java code working on the widget-api
from that angle you could also just use that API yourself and make sure
the latitude property is present before you call the binding (I mean:
rather then doing that from inside the binding. It's really a matter of
contract: "what are the pre-conditions for calling that particular
binding..." if you negotiate the contract with yourself, then it often
boils down to a quite arbitrary decission: just pick the approach that
makes you happy)
> For the simple cases, <fb:insert-bean> will work nicely. In some cases
> however, I will need to first check if there is an object already
> there. Something like:
>
> if( report.getLatitude() == null )
> report.setLatitude(new GeoCoordinate());
>
yep, but you could also just do this in flow-script before calling
form.save(report)
> In that case, I think I will use <fb:javascript>. The only problem is
> that <fb:javascript> takes the ID of a widget. This initialization
> doesn't really apply to any widget in particular...
>
I'ld have to check, but I am afraid it is indeed required here and now
if you have the time to check (and can confirm) it might be wise to add
this to the bugzilla...
(meaning: I agree, just like context and custom it should be able to
work without an id, just don't have time here and now, and bugzilla will
help us remember, and possibly inspire people to send in the patch)
while waiting for that patch you can just give it 'some' id, it will not
harm you since you will not use the reference to the widget in your
script anyway (cut and paste reusability of that part of the binding is
the only thing that get's harmed a bit)
regards,
-marc=
> Benoit Deshaies
>
> --- Marc Portier <mp...@outerthought.org> wrote:
>
> http://cocoon.apache.org/2.1/userdocs/forms/binding.html#fb%3Ainsert-bean
>
>>try something along the lines of
>><fb:insert-bean classname="GeoCoordinate" addmethod="setLatitude" />
>>
>>before the <fb:value> stuff on the latitude
>>
>>this assumes that GeoCoordinate has a constructor that doesn't
>>require
>>any arguments, and that your SightingReport has a
>>setLatitude(GeoCoordinate) method (the latter is already assumed by
>>the
>>use of jxpath per the paths in your snippet)
>>
>>alternatively you could indeed use the javascript or custom binding
>>(the first probably somewhat easier)
>>
>>HTH,
>>-marc=
>>
>>Benoit Deshaies wrote:
>>
>>>Hi,
>>>
>>>I was wondering what was the simplest way to use the Forms Binding
>>>Framework to create new objects. I have the following Java model I
>>>created a form for:
>>>
>>>public class SightingReport {
>>> private String birdName;
>>> private GeoCoordinate latitude;
>>> // gets/sets
>>>}
>>>
>>>public class GeoCoordinate {
>>> private int deg;
>>> private int min;
>>> private int sec;
>>> // gets/sets
>>>}
>>>
>>>SightingReport.latitude is initialized to null. My binding file
>>
>>looks
>>
>>>like this:
>>>
>>><fb:context path="/" >
>>> <fb:value id="birdName" path="birdName"/>
>>> <fb:value id="latDeg" path="latitude/deg"/>
>>> <fb:value id="latMin" path="latitude/min"/>
>>> <fb:value id="latSec" path="latitude/sec"/>
>>></fb:context>
>>>
>>>When I invoke form.save(sightingReport), I get the following error:
>>>Exception trying to create xpath latitude/deg; Factory is not set
>>
>>on
>>
>>>the JXPathContext - cannot create path: /latitude.
>>>
>>>What would be The Best Way to initialize the latitude object
>>
>>(invoke
>>
>>>default constructor) ? <fb:javascript> ? <fb:custom> ?
>>>
>>>Many thanks,
>>>
>>>Benoit Deshaies
>
>
>
>
>
>
>
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--
Marc Portier http://outerthought.org/
Outerthought - Open Source, Java & XML Competence Support Center
Read my weblog at http://blogs.cocoondev.org/mpo/
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Re: CForm binding: creating objects?
Posted by Benoit Deshaies <bd...@yahoo.com>.
Many thanks Marc. That's exactly what I was looking for. For some
reason, I had assumed this was just to add an item to a Collection...
For the simple cases, <fb:insert-bean> will work nicely. In some cases
however, I will need to first check if there is an object already
there. Something like:
if( report.getLatitude() == null )
report.setLatitude(new GeoCoordinate());
In that case, I think I will use <fb:javascript>. The only problem is
that <fb:javascript> takes the ID of a widget. This initialization
doesn't really apply to any widget in particular...
Benoit Deshaies
--- Marc Portier <mp...@outerthought.org> wrote:
>
http://cocoon.apache.org/2.1/userdocs/forms/binding.html#fb%3Ainsert-bean
>
> try something along the lines of
> <fb:insert-bean classname="GeoCoordinate" addmethod="setLatitude" />
>
> before the <fb:value> stuff on the latitude
>
> this assumes that GeoCoordinate has a constructor that doesn't
> require
> any arguments, and that your SightingReport has a
> setLatitude(GeoCoordinate) method (the latter is already assumed by
> the
> use of jxpath per the paths in your snippet)
>
> alternatively you could indeed use the javascript or custom binding
> (the first probably somewhat easier)
>
> HTH,
> -marc=
>
> Benoit Deshaies wrote:
> > Hi,
> >
> > I was wondering what was the simplest way to use the Forms Binding
> > Framework to create new objects. I have the following Java model I
> > created a form for:
> >
> > public class SightingReport {
> > private String birdName;
> > private GeoCoordinate latitude;
> > // gets/sets
> > }
> >
> > public class GeoCoordinate {
> > private int deg;
> > private int min;
> > private int sec;
> > // gets/sets
> > }
> >
> > SightingReport.latitude is initialized to null. My binding file
> looks
> > like this:
> >
> > <fb:context path="/" >
> > <fb:value id="birdName" path="birdName"/>
> > <fb:value id="latDeg" path="latitude/deg"/>
> > <fb:value id="latMin" path="latitude/min"/>
> > <fb:value id="latSec" path="latitude/sec"/>
> > </fb:context>
> >
> > When I invoke form.save(sightingReport), I get the following error:
> > Exception trying to create xpath latitude/deg; Factory is not set
> on
> > the JXPathContext - cannot create path: /latitude.
> >
> > What would be The Best Way to initialize the latitude object
> (invoke
> > default constructor) ? <fb:javascript> ? <fb:custom> ?
> >
> > Many thanks,
> >
> > Benoit Deshaies
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Re: CForm binding: creating objects?
Posted by Marc Portier <mp...@outerthought.org>.
http://cocoon.apache.org/2.1/userdocs/forms/binding.html#fb%3Ainsert-bean
try something along the lines of
<fb:insert-bean classname="GeoCoordinate" addmethod="setLatitude" />
before the <fb:value> stuff on the latitude
this assumes that GeoCoordinate has a constructor that doesn't require
any arguments, and that your SightingReport has a
setLatitude(GeoCoordinate) method (the latter is already assumed by the
use of jxpath per the paths in your snippet)
alternatively you could indeed use the javascript or custom binding
(the first probably somewhat easier)
HTH,
-marc=
Benoit Deshaies wrote:
> Hi,
>
> I was wondering what was the simplest way to use the Forms Binding
> Framework to create new objects. I have the following Java model I
> created a form for:
>
> public class SightingReport {
> private String birdName;
> private GeoCoordinate latitude;
> // gets/sets
> }
>
> public class GeoCoordinate {
> private int deg;
> private int min;
> private int sec;
> // gets/sets
> }
>
> SightingReport.latitude is initialized to null. My binding file looks
> like this:
>
> <fb:context path="/" >
> <fb:value id="birdName" path="birdName"/>
> <fb:value id="latDeg" path="latitude/deg"/>
> <fb:value id="latMin" path="latitude/min"/>
> <fb:value id="latSec" path="latitude/sec"/>
> </fb:context>
>
> When I invoke form.save(sightingReport), I get the following error:
> Exception trying to create xpath latitude/deg; Factory is not set on
> the JXPathContext - cannot create path: /latitude.
>
> What would be The Best Way to initialize the latitude object (invoke
> default constructor) ? <fb:javascript> ? <fb:custom> ?
>
> Many thanks,
>
> Benoit Deshaies
>
>
>
>
> __________________________________
> Do you Yahoo!?
> Friends. Fun. Try the all-new Yahoo! Messenger.
> http://messenger.yahoo.com/
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@cocoon.apache.org
> For additional commands, e-mail: users-help@cocoon.apache.org
>
--
Marc Portier http://outerthought.org/
Outerthought - Open Source, Java & XML Competence Support Center
Read my weblog at http://blogs.cocoondev.org/mpo/
mpo@outerthought.org mpo@apache.org
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