Smalltalk › Pharo › Pharo Smalltalk Developers

doc on ob requests and commands

_‹ Previous Topic Next Topic _›

Classic

List

Threaded

7 messages Options

Tudor Girba

doc on ob requests and commands

Hi,

I am browsing OB to understand the design of the Requests and the commands. In particular, I am interested to understand why OBRequests are Notifications and how they link with the commands.

Is there anywhere I can read about it?

Cheers,
Doru

--
www.tudorgirba.com

"What we can governs what we wish."

Lukas Renggli

Re: doc on ob requests and commands

> I am browsing OB to understand the design of the Requests and the commands. In particular, I am interested to understand why OBRequests are Notifications and how they link with the commands.
>
> Is there anywhere I can read about it?

Please check the class comments of OBInteractionRequest and subclasses.

"OBInteractionRequest is an abstract superclass for notifications that
request some interaction with the user. It's useful for catching such
notifications in an exception handler, while allowing other
notifications to operate normally."

So all these requests are interacting in some way with the user, e.g.
they open a new browser, they close a browser, they refresh a browser,
they show a specific dialog, they change the mouse cursor, etc. And
depending on the current view these requests are handled differently.
In OB-Morphic the respective morphic actions are performed, in OB-Web
the request is serialized to JSON and performed on the client side,
... and in the tests the events are silently captured and verified
using assertions.

OBCommand is something entirely different. It represents the
first-class actions (menu items, buttons) in a browser. The only way
an OBCommand can interact with the user and for example request
additional information is through OBInteractionRequests that might be
triggered at any point.

Lukas

--
Lukas Renggli
www.lukas-renggli.ch

Tudor Girba

Re: doc on ob requests and commands

Thanks, Lukas.

I did read the comments. I understand why Commands and Requests are first class entities, and what they do individually. In Glamour, we have Actions which are similar to OB Commands. However, now we do not have explicit Requests, and I wanted to learn from OB.

My main current question is what are the reasons for OBInteractionRequest to subclass Notification?

Cheers,
Doru

On 23 Jan 2011, at 23:34, Lukas Renggli wrote:

>> I am browsing OB to understand the design of the Requests and the commands. In particular, I am interested to understand why OBRequests are Notifications and how they link with the commands.
>>
>> Is there anywhere I can read about it?
>
> Please check the class comments of OBInteractionRequest and subclasses.
>
> "OBInteractionRequest is an abstract superclass for notifications that
> request some interaction with the user. It's useful for catching such
> notifications in an exception handler, while allowing other
> notifications to operate normally."
>
> So all these requests are interacting in some way with the user, e.g.
> they open a new browser, they close a browser, they refresh a browser,
> they show a specific dialog, they change the mouse cursor, etc. And
> depending on the current view these requests are handled differently.
> In OB-Morphic the respective morphic actions are performed, in OB-Web
> the request is serialized to JSON and performed on the client side,
> ... and in the tests the events are silently captured and verified
> using assertions.
>
> OBCommand is something entirely different. It represents the
> first-class actions (menu items, buttons) in a browser. The only way
> an OBCommand can interact with the user and for example request
> additional information is through OBInteractionRequests that might be
> triggered at any point.
>
> Lukas
>
> --
> Lukas Renggli
> www.lukas-renggli.ch
>

--
www.tudorgirba.com

"Being happy is a matter of choice."

Lukas Renggli

Re: doc on ob requests and commands

> My main current question is what are the reasons for OBInteractionRequest to subclass Notification?

To be able to perform user interactions anywhere without having a
global OBPlatform instance, and without having to pass OBPlatform in
or store OBPlatform anywhere. There can be multiple UI platforms
active at the same time and they can even change over the lifetime of
a single browser window.

Lukas

--
Lukas Renggli
www.lukas-renggli.ch

Tudor Girba

Re: doc on ob requests and commands

Hi Lukas,

On 24 Jan 2011, at 15:57, Lukas Renggli wrote:

>> My main current question is what are the reasons for OBInteractionRequest to subclass Notification?
>
> To be able to perform user interactions anywhere without having a
> global OBPlatform instance, and without having to pass OBPlatform in
> or store OBPlatform anywhere. There can be multiple UI platforms
> active at the same time and they can even change over the lifetime of
> a single browser window.

I am not sure I understand. Why did it have to be a subclass of Notification? Would it not be enough to have it as a subclass of Object?

Cheers,
Doru

> Lukas
>
> --
> Lukas Renggli
> www.lukas-renggli.ch
>

--
www.tudorgirba.com

"The coherence of a trip is given by the clearness of the goal."

Dale Henrichs

Re: doc on ob requests and commands

On 01/24/2011 01:07 PM, Tudor Girba wrote:

> Hi Lukas,
>
> On 24 Jan 2011, at 15:57, Lukas Renggli wrote:
>
>>> My main current question is what are the reasons for OBInteractionRequest to subclass Notification?
>>
>> To be able to perform user interactions anywhere without having a
>> global OBPlatform instance, and without having to pass OBPlatform in
>> or store OBPlatform anywhere. There can be multiple UI platforms
>> active at the same time and they can even change over the lifetime of
>> a single browser window.
>
> I am not sure I understand. Why did it have to be a subclass of Notification? Would it not be enough to have it as a subclass of Object?
>
> Cheers,
> Doru

Doru,

They are subclasses of Notification so that exception handlers can be
used to intercept the notification and do something different than
prompt the user for the request ... the defaultAction of the exception
triggers the UI to prompt the user with an appropriate dialog box...

Dale

Lukas Renggli

Re: doc on ob requests and commands

In reply to this post by Tudor Girba

Performing a user interaction always goes through signaling the
notification. For example to request a text input:

expression := OBTextRequest new
prompt: 'Enter a matching expression';
signal

Or to open the completion dialog:

category := OBCompletionRequest new
assisted: true;
collection: categories;
prompt: 'Add Category';
signal

Or to open a new browser:

view := OBBrowseRequest new
browser: OBSystemBrowser new;
signal

Note that Morphic raises some interaction notifications in a very
hackish too (with information stuffed into arrays and dictionaries)
when opening some (of course not all) of the user interactions. OB
implemented its own user interaction mechanism long before Morphic was
improved and also to remain independent of the platform/view.

Lukas

On 24 January 2011 13:07, Tudor Girba <[hidden email]> wrote:

--
Lukas Renggli
www.lukas-renggli.ch