There is actually an alternate way of doing autocomplete that is
easier, and for now both will exist as the opinions and discussions
around them have diverged.
On the drop-down element in the form widget there is a "type"
attribute that has two option: "traditional", "auto-complete-server".
The "traditional" one is the default. If you set it to "auto-complete-
server" then it will render a text box and when you start typing it
will do a server-side autocomplete and show options based on what has
been typed in.
The design goals are these:
1. setting this attribute is all that needs to be done to do an
autocomplete
2. it is a variation of the drop-down because the query constraints to
use in the autocomplete are the same as are needed for a drop-down;
when the auto-complete query is done these constraints will be used
plus one additional constraint to filter the displayed fields
(according to the content of the description shown in drop-down/
autocomplete box)
3. no custom code is required; a generic event will be the target of
the background server request and it will simply include the name of
the form and the name of the field and the partial text entered as
parameters, leaving all control of the query constraints in the form
definition (ie on the drop-down element with the type="auto-complete-
server" attribute); for more security the session would be used with a
key added as a session attribute that would be specified in a request
parameter and used to look the field and form names in the session
(preset by the form widget while rendering); that is important because
security is normally controlled in views using screen section
conditions, and those would be skipped when getting autocomplete
options, opening the door to spoofing parameters
In general the idea with the form and screen widgets are to make
things as easy as possible, requiring no additional programming to
have access to features, just specify the options desired.
The XSD has been modified for the above, and someone was going to work
on implementing this after the initial commit to the XSD, but I guess
it hasn't been finished yet (I took at peek at the
ModelFormField.DropDown class and didn't see anything there yet).
-David
On Jun 22, 2008, at 1:40 PM, Scott Gray wrote:
Hi Adrian
Thanks for explanation, but isn't an autocomplete something that
could just
as easily be used in a swing environment? I don't see anything
about it's
behaviour that is ajax specific. The more I think about it I see
can't why
we don't just have an autocomplete element, all we'd be telling the
platform
specific renderer to do is take the user input and search a list of
values
for any matches then show them to the user so they can select one.
Regards
Scott
2008/6/23 Adrian Crum <[EMAIL PROTECTED]>:
--- On Sun, 6/22/08, Scott Gray <[EMAIL PROTECTED]> wrote:
While we're (sort of) on the topic of the
autocomplete, does anybody really
find the following intuitive?
<field name="exampleFeatureId"
id-name="exampleFeatureId">
<text/>
<on-field-event-update-area
event-type="change"
area-id="exampleFeatureId"
area-target="findExampleFeatures"/>
</field>
The ajax stuff is still being developed. One thing that was
suggested was
to have an additional attribute to describe the type of server-side
action:
<on-field-event-update-area
event-type="change"
area-id="exampleFeatureId"
area-target="findExampleFeatures"
server-action="autocomplete"/>
I can't think of a better element name. It's expressing "On a field
event,
update an area of the screen."
The event type (in the HTML world) would be either change or click.
The area id is the area (HTML container) to be updated when the event
occurs.
The area target is the URL called to update the area specified in
area-id.
The server action is a description of what type of response the
server will
put in the area.
If anyone has suggestions for better names, then this is a good
time to
make them - before we get any further into Ajax development. Just
keep in
mind that the syntax shouldn't be Ajax-specific - because the
widgets are
intended to support more than one rendering format. Also keep in
mind that
more than one ajax event can be triggered by a field event.
-Adrian
