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Qt-jambi-interest Archive, August 2006
Serialization


Message 1 in thread

Hi,

I have noticed QObject and everything below it is not serializable (through 
the interface serializable). Is it not possible to serialize Qt?

David


Message 2 in thread

On Thursday 17 August 2006 13:25, David Naylor wrote:
> Hi,
>
> I have noticed QObject and everything below it is not serializable (through
> the interface serializable). Is it not possible to serialize Qt?
>
> David

Hi David,

please give us some more information. Can you describe a usage case where you 
used serialization of GUI objects, with e.g. Swing? How well is this 
currently supported in SWT?


Matthias


Message 3 in thread

Hi Matthias

I'm sorry but I have never used serialization for any GUI object.  The only 
reason I have noticed this is I was trying to serialize a class that extends 
QObject and uses QSingal*.  I do think serialization would be nice on QDate, 
QVariant and similar.  

As far as I know, all of Swing is serializable but I have never done anything 
with that.  One hyperthetical use is streaming GUI's across networks and 
such.  The python equivalent of dynamicly loading ui files (from a file)?  

Just a suggestion, someone might have a need to use it but if I understand how 
Qt-Jambi works, all the data is stored in c++, which could be a big problem 
to make serializable in java.

David

On Thursday 17 August 2006 18:04, Matthias Ettrich wrote:
> On Thursday 17 August 2006 13:25, David Naylor wrote:
> > Hi,
> >
> > I have noticed QObject and everything below it is not serializable
> > (through the interface serializable). Is it not possible to serialize Qt?
> >
> > David
>
> Hi David,
>
> please give us some more information. Can you describe a usage case where
> you used serialization of GUI objects, with e.g. Swing? How well is this
> currently supported in SWT?
>
>
> Matthias


Message 4 in thread

If we would like to use Qt Jambi for something like Java Web Start or 
instant client, we would need to have serialized objects.

Have there been any consideration about using Qt Jambi in Java Web Start 
  applications ?

Reidar M. Sollid

David Naylor wrote:
> Hi Matthias
> 
> I'm sorry but I have never used serialization for any GUI object.  The only 
> reason I have noticed this is I was trying to serialize a class that extends 
> QObject and uses QSingal*.  I do think serialization would be nice on QDate, 
> QVariant and similar.  
> 
> As far as I know, all of Swing is serializable but I have never done anything 
> with that.  One hyperthetical use is streaming GUI's across networks and 
> such.  The python equivalent of dynamicly loading ui files (from a file)?  
> 
> Just a suggestion, someone might have a need to use it but if I understand how 
> Qt-Jambi works, all the data is stored in c++, which could be a big problem 
> to make serializable in java.
> 
> David
> 
> On Thursday 17 August 2006 18:04, Matthias Ettrich wrote:
>> On Thursday 17 August 2006 13:25, David Naylor wrote:
>>> Hi,
>>>
>>> I have noticed QObject and everything below it is not serializable
>>> (through the interface serializable). Is it not possible to serialize Qt?
>>>
>>> David
>> Hi David,
>>
>> please give us some more information. Can you describe a usage case where
>> you used serialization of GUI objects, with e.g. Swing? How well is this
>> currently supported in SWT?
>>
>>
>> Matthias
> 
> 
> 
> 


Message 5 in thread

Reidar M. Sollid wrote:

>
> If we would like to use Qt Jambi for something like Java Web Start or 
> instant client, we would need to have serialized objects.
> Have there been any consideration about using Qt Jambi in Java Web 
> Start  applications ?

Hi, Reidar.

Yes, we have experimented with this and successfully run the Qt Jambi 
Demo Launcher with Java Web Start. What do you need serializable objects 
for in your Web Start application?

-- Eskil


Message 6 in thread


Eskil A. Blomfeldt wrote:
> Reidar M. Sollid wrote:
> 
>>
>> If we would like to use Qt Jambi for something like Java Web Start or 
>> instant client, we would need to have serialized objects.
>> Have there been any consideration about using Qt Jambi in Java Web 
>> Start  applications ?
> 
> Hi, Reidar.
> 
> Yes, we have experimented with this and successfully run the Qt Jambi 
> Demo Launcher with Java Web Start. What do you need serializable objects 
> for in your Web Start application?
> 
> -- Eskil
> 
> 
> 

Hi Eskil,

If you you have made it without serializable objects I can not think of 
any. Sorry my mistake.

Reidar


Message 7 in thread

Reidar M. Sollid wrote:
> 
> 
> Eskil A. Blomfeldt wrote:
>> Reidar M. Sollid wrote:
>>
>>>
>>> If we would like to use Qt Jambi for something like Java Web Start or 
>>> instant client, we would need to have serialized objects.
>>> Have there been any consideration about using Qt Jambi in Java Web 
>>> Start  applications ?
>>
>> Hi, Reidar.
>>
>> Yes, we have experimented with this and successfully run the Qt Jambi 
>> Demo Launcher with Java Web Start. What do you need serializable 
>> objects for in your Web Start application?
>>
>> -- Eskil
>>
>>
>>
> 
> Hi Eskil,
> 
> If you you have made it without serializable objects I can not think of 
> any. Sorry my mistake.
> 
> Reidar
> 

And of course, Java Web Start is moving a jar file and not objects. Must 
have been a bit tired yesterday :)

Reidar


Message 8 in thread

On Thursday 17 August 2006 22:56, David Naylor wrote:
> I'm sorry but I have never used serialization for any GUI object.  The
> only reason I have noticed this is I was trying to serialize a class
> that extends QObject and uses QSingal*.  I do think serialization would
> be nice on QDate, QVariant and similar.

For various frameworks I build the on-the-wire communication was 
serialized Java objects which makes it very convenient to communicate 
without having to write your own xml writer/readers. This is a great 
feature that is used by many.  This in contrast to serializing Swing 
objects. While i have seen some companies use that, its mostly because 
they didn't know a better way.

Many data objects that Qt provides have serializable equivalents in the 
Java standard library, so an easy way to go is to just provide methods 
that will allow you to do the relevant conversions.

For example;
   QDate (the Java class) would have
   public java.util.Date toDate();
   public static QDate fromDate(java.util.Date date);

That said; I have no experience in mixing JNI and serializable, so maybe 
its really easy to get support if you try :)
-- 
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