Re: [Lazarus] WebDataProvider's Factory Support
On Sun, 24 Oct 2010, Leonardo M. Ramé wrote:
I'm trying to understand how does factory support works for
WebDataProvider.
Is this feature useful when the programmer don't want to add too many
WebDataProviders into the TFPWebProviderDataModule?.
yes.
It is possible to define the WebDataProviders in their own unit (by
code), then, in the TFPWebProviderDataModule register all providers with
RegisterProvider,
to let the module know about them?.
You can do this.
How we work at my job is: create N datamodules with WebDataProviders,
and at program startup, register all the datamodules in the factory.
There is exactly 1 TFPWebProviderDataModule which has the option set
to check the factory registry. It is registered with URL /Providers.
If factory support's rationale is to avoid WebProviderDataModules full
of WebDataProviders, why not just divide the app with many
datamodules containing only some WebDataProviders?.
To have a single url. If you make many TFPWebProviderDataModules, they must all
be registered with their own URL. The factory system allows to have a single
entry point.
All providers in my application are then accessible from
/Providers/ProviderName/Read
(and of course create/update/delete)
I created a Ext.data.Store descendent which has the URL and naming scheme
coded in so all I must do is
mystore = new WISA.ClientDataset ({
ProviderName : 'MyData'
});
To access the data.
Michael.--
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Re: [Lazarus] WebDataProvider's Factory Support
On 2010-10-24 20:44:28 +0200, Michael Van Canneyt wrote: It is possible to define the WebDataProviders in their own unit (by code), then, in the TFPWebProviderDataModule register all providers with RegisterProvider, to let the module know about them?. You can do this. How we work at my job is: create N datamodules with WebDataProviders, and at program startup, register all the datamodules in the factory. There is exactly 1 TFPWebProviderDataModule which has the option set to check the factory registry. It is registered with URL /Providers. Ok, that way all datamodules (except the one that you mentioned) are just containers of WebDataProviders, until the moment where a request needs one of them, then, the factory creates an instance of the required one. Much clear now, thanks Michael. -- Leonardo M. Ramé http://leonardorame.blogspot.com -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
