[Engine-devel] [engine-devel] frontend builders proposal

Gilad Chaplik gchaplik at redhat.com
Wed Jan 30 10:42:22 UTC 2013 

----- Original Message -----
> From: "Tomas Jelinek" <tjelinek at redhat.com>
> To: "Gilad Chaplik" <gchaplik at redhat.com>
> Cc: engine-devel at ovirt.org
> Sent: Wednesday, January 30, 2013 11:11:41 AM
> Subject: Re: [Engine-devel] [engine-devel] frontend builders proposal
> 
[adding missing part from the thread]

> I agree that this refactoring can significantly help us reduce code
> complexity,
> there is another issue that your suggestion doesn't address,
> but we may want take the opportunity to address it if we are already
> considering refactoring for this code:

> > this dialog demonstrates the greatest difference (IMHO) between
> > server side pages to applets,
> > the back and forth filling the form by retrieving all elements one
> > by one.
> > I would think of a concept similar to server side pages, i.e.
> > retrieving all
> > data, visibility and even validations (compat?), in a single
> > request, and let the
> > server have the logic.
> Not sure if I have understood you correctly - do you mean moving the
> frontend logic (e.g. visibility of fields according to some
> selection) and also the frontend models
> to the server? I would say it is better to have this on FE.

IMHO, we should uiqeury (or something similar) or uiplugin (or striving towards it), that get the entire dialog data (with /without ui).
I'm not sure what is the benefit with your refactoring, can you elaborate on that?

but let see what others think.

> 
> However having the validations common between FE and BE would be
> great. We could prepare a different patch for this.

I think that common validations are nice to have, and it is least of our problems.

> 
> 
> ----- Original Message -----
> From: "Gilad Chaplik" <gchaplik at redhat.com>
> To: "Tomas Jelinek" <tjelinek at redhat.com>
> Cc: engine-devel at ovirt.org, "Eli Mesika" <emesika at redhat.com>
> Sent: Monday, January 28, 2013 5:08:41 PM
> Subject: Re: [Engine-devel] [engine-devel] frontend builders proposal
> 
> ----- Original Message -----
> > From: "Eli Mesika" <emesika at redhat.com>
> > To: "Tomas Jelinek" <tjelinek at redhat.com>
> > Cc: engine-devel at ovirt.org
> > Sent: Saturday, January 26, 2013 10:58:57 PM
> > Subject: Re: [Engine-devel] [engine-devel] frontend builders
> > proposal
> > 
> > 
> > 
> > ----- Original Message -----
> > > From: "Tomas Jelinek" <tjelinek at redhat.com>
> > > To: engine-devel at ovirt.org
> > > Sent: Friday, January 25, 2013 11:55:43 AM
> > > Subject: [Engine-devel] [engine-devel] frontend builders proposal
> > > 
> > > Hi All,
> > > 
> > > as many of you may know, the way how the frontend and backend
> > > models
> > > are built on frontend (uicommonweb project) is not really ideal.
> > > Currently this logic is copy pasted over and over again to
> > > different
> > > places where it is needed with minor changes to fulfill the
> > > specific
> > > requirements. It is not only aesthetically problematic, but I
> > > recall
> > > tons of bugs caused by introducing a new field and forgetting to
> > > add
> > > it to every place it is used in GUI.
> > > 
> > > Now, as there will be big changes in the VM/Template models
> > > (http://www.ovirt.org/Features/Instance_Types), so the way how
> > > the
> > > VM, Template, Pool and also the newly created Instance Types
> > > models
> > > are being built has to be touched anyhow, it is a great
> > > opportunity
> > > to rethink the way how we do it.
> > > 
> > > I have created a simple infrastructure
> > > (http://gerrit.ovirt.org/#/c/10874/) which could be used for it,
> > > and
> > > a PoC patch which uses this infrastructure
> > > (http://gerrit.ovirt.org/#/c/11354/). Please note that the PoC is
> > > not really impressive in means of removing duplications, I wanted
> > > to
> > > start with the simplest possibility.
> > > 
> > > The principles behind the infrastructure:
> > > - have small, well named, easy to understand and reuse builders
> > > - this builders can be chained together or embedded to each other
> > > to
> > > build the full resulting object (composite pattern)
> > > - this builders can be asynchronous, and the next builder in the
> > > chain has to be executed only when the current is completely done
> > > 
> > > The structure:
> > > - the base is an interface called Builder which has a method
> > > build(source, destination, rest)
> > > - the builder implementing this interface
> > >   + will get the source and destination objects
> > >   + copies whatever he wants from source to destination
> > >   + when done, executes build on the first element of the rest
> > >     + this may sound awkward, but this is the way how the async
> > >     calls
> > >     can be "linearized" in a general way, not embedding anonymous
> > >     class into anonymous
> > >       class into anonymous class... as we do it today.
> > >     + for synchronous builders, there is a BaseSyncBuilder which
> > >     takes care of this boilerplate calling of next and exposes a
> > >     simple method
> > >       build(S source, D destination)
> > >   + to simplify the creating and running the chain of builders,
> > >   there
> > >   is a BuilderExecutor class (can be created as sync or async)
> > > 
> > > So, a simple example - even more simple than the PoC patch :)
> > > 
> > > //create the first builder
> > > class FirstLetterBuilder extends BaseSyncBuilder<String,
> > > StringBuilder> {
> > >  @Override
> > >  protected void build(String source, StringBuilder destination) {
> > >      // copy the first letter to the destination
> > >      destination.append(source.charAt(0));
> > >  }
> > > }
> > > 
> > > //create the second builder
> > > class SecondLetterBuilder extends BaseSyncBuilder<String,
> > > StringBuilder> {
> > >  @Override
> > >  protected void build(String source, StringBuilder destination) {
> > >      // copy the second letter to the destination
> > >      destination.append(source.charAt(1));
> > >  }
> > > }
> > > 
> > > // usage
> > > ...
> > > // create the destination object
> > > StringBuilder res = new StringBuilder();
> > > 
> > > // configure the executor with the two builders
> > > BuilderExecutor<String, StringBuilder> executor = new
> > > BuilderExecutor<String, StringBuilder>(
> > >         new FirstLetterBuilder(),
> > >         new SecondLetterBuilder()
> > >         );
> > > 
> > > // execute the builder chain ("ab" is the source, res the
> > > destination)
> > > executor.build("ab", res);
> > > 
> > > // use the result
> > > ...
> > > 
> > > That's it. And the nice part is, that this FirstLetterBuilder and
> > > SecondLetterBuilder can be reused anywhere or combined with any
> > > other builders.
> > > 
> > > Any comments on this will be more than welcome!
> > 
> > great and really simplifies work and eliminate bugs resulted from
> > copy/past code
> > gave +1
> > Thanks
> > Eli
> 
> Hi guys,
> 
> I agree that this refactoring can significantly help us reduce code
> complexity,
> there is another issue that your suggestion doesn't address,
> but we may want take the opportunity to address it if we are already
> considering refactoring for this code:
> this dialog demonstrates the greatest difference (IMHO) between
> server side pages to applets,
> the back and forth filling the form by retrieving all elements one by
> one.
> I would think of a concept similar to server side pages, i.e.
> retrieving all
> data, visibility and even validations (compat?), in a single request,
> and let the
> server have the logic.
> 
> Thanks,
> Gilad.
> 
> > > 
> > > Thank you,
> > > Tomas
> > > _______________________________________________
> > > Engine-devel mailing list
> > > Engine-devel at ovirt.org
> > > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > > 
> > _______________________________________________
> > Engine-devel mailing list
> > Engine-devel at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/engine-devel
> > 
>

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