Hi,

Theoretically you are absolutely right. But practically is another
discussion, I am talking about thousands of lines that need to change just
for the GUI tier limitations. The GUI is just a fraction of the application
because the same Request/Response objects are used internally as well
(command pattern). Redesigning the entire application because of a
limitation of the GUI is nuts. But in the way we use BigInteger, I
understand your point of view.

But the same problem is there with BigDecimal (somebody else filled an
issue so I did not bother to create a duplicate, it is marked as assume
stale).

We show records with BigDecimal in Cell tables. Again RPC is slow here.
While the user will only click on certain records to make modifications.
Again I could refactor to wait with conversion to BigDecimal until the user
changes a value (to validate), but in this case BigDecimal was the right
data-type to use and it is not nice to have to redesign an application
because the RPC system of GWT has limitations.

David

On Thu, Jun 13, 2013 at 10:20 PM, Brian Slesinsky <[email protected]>wrote:

> I agree; this seems like a workaround for one application that picked the
> wrong datatype. Maybe we should warn about BigDecimal being slow somewhere?
> If someone wants to do some performance tests of GWT-RPC serialization,
> publishing the results would be useful to the community.
>
> My recommendation in this case would be create a new class named "Id" or
> Key" that simply contains the BigDecimal, then modify the code to use it,
> then change the implementation to store the data in a string field instead.
> In the end you'll have more readable code.
>
> - Brian
>
>
> On Thu, Jun 13, 2013 at 12:03 PM, David <[email protected]> wrote:
>
>> John,
>>
>> Well, if I don't have support for this patch then I better stop working
>> on it. I can understand that this is not seen as a priority for GWT. Worst
>> case I just replace the BigInteger/BigDecimal class in the project itself,
>> that is basically what I did right now.
>>
>> Oracle sequences can be configured as a range between -10ˆ-26 and 10ˆ27.
>> The Oracle JDBC drivers return
>> a BigInteger if you force it to the extremes.
>>
>> Changing the application is not feasible, that will be too much work, we
>> are talking about many thousands of dependencies in a huge codebase where
>> BigIntegers and BigDecimals are used - while handling this optimisation on
>> the RPC level can be done in just a few lines of code.
>>
>> In many cases we send large lists of objects that contain BigInteger,
>> BigDecimals but only a few will actually be interacted with. So in that
>> case we only need to convert the Strings to BigInteger (or BigDecimal) when
>> really needed.
>>
>> David
>>
>> On Thu, Jun 13, 2013 at 7:52 PM, John A. Tamplin <[email protected]> wrote:
>>
>>> On Thu, Jun 13, 2013 at 3:14 AM, David <[email protected]> wrote:
>>>
>>>> The lazy parsing would only happen during deserialisation in the
>>>> client. I think it is safe to assume that a BigInteger created through
>>>> toString on the server will not result in a parse exception in the client
>>>> code - or are there known incompatibilities ?
>>>>
>>>> I don't want that the regular constructor of BigInteger( String ) or
>>>> BigInteger( String, int) would behave differently than before. Not even in
>>>> the client when those BigInts are created in the client. That's why I was
>>>> asking about the possibility to have different serialisers on client and
>>>> server side.
>>>>
>>>> As the why, well currently the custom field serializer converts the
>>>> BigInteger to a String, the client side needs to parse the string and
>>>> convert it to an int array, which involves multiple substring,
>>>> Integer.parseInt and multiply and add operations. Somehow IE8 has a problem
>>>> with this. IE9 and other browsers are more efficient, but still that is a
>>>> lot of CPU operations that can be avoided in my use case.
>>>>
>>>> In my particular use case they used BigInteger to represent a key in
>>>> the database (oracle uses sequence numbers that are bigger than what can be
>>>> represented with long). That might have not been the best idea, but those
>>>> decisions have been made a long time ago, when I was not around. On the
>>>> server side there is a usage of equals and compareTo happening, which would
>>>> be hard to implement without a BigInteger, so there is logic in the choice.
>>>> They obviously don't want to have an extra layer of objects to avoid the
>>>> BigInteger in the GWT client since a lot of code is independent of client
>>>> or server, this would hinder code sharing between the tiers.
>>>>
>>>> On the client side these id's are only send forth and back between
>>>> client and server, no operation is ever performed, so making the custom
>>>> field serialiser and the BigInteger cooperate gives a big performance
>>>> improvement. They only operation needed on the client-side is equals,
>>>> which can also be optimized to do a String comparison when bother have not
>>>> been parsed after RPC.
>>>>
>>> 
>>> I'm beginning to think such a change does not belong in GWT.  In your
>>> example, wouldn't you be better served by only sending strings to the
>>> client rather than BigDecimals, if they client never does anything with
>>> them but send them back?  I think it is going to be pretty rare in normal
>>> situations that you instantiate a BigDecimal but never actually use it in
>>> the client, so it seems the special-case hack for your use-case should be
>>> performed in your code instead.
>>>
>>> Too often people want to send things to the client that really don't
>>> belong there, and that includes particular representations of it.  I know
>>> DTOs are extra work over just shipping your regular objects over the wire
>>> and GWT RPC makes that easy, but in many cases it is the wrong thing to do.
>>>  Think about if you were building a proto for the communication -- would
>>> you send the data in the current form?  If not, you shouldn't be sending it
>>> that way via RPC just because it is easy to do so.
>>>
>>> BTW, I thought Oracle sequence numbers did fit in long (aren't they
>>> int64?) -- at least all the JDBC code I see for manipulating them stores
>>> them in a Java long.
>>>
>>> --
>>> John A. Tamplin
>>>
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>>> http://groups.google.com/group/Google-Web-Toolkit-Contributors
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