Hi Malcolm,
Haven't thought this through but we could have the following interface:
public DataProvider {
public List getData(int start, int count);
public int getSize();
}
Example impl:
final MyDao dao = ...
table.setDataProvider(new DataProvider() {
public List getData(int start, int count) {
return dao.getCustomers(start, count);
}
public int getSize() {
return dao.getNumberOfCustomers();
}
}
kind regards
bob
On 23/02/2010 09:29 PM, Malcolm Edgar wrote:
I have been thinking more about this, and the more I like it.
One of the most common newie bugs we see with Click is the
inappropriate use of the Page#onRender() method, i.e. people adding
controls too late to a page to be processed or not initializing Form,
Select, FormTable with data.
Using a DataProvider the controls can pull the data when they need
need it, rather than developers having to anticipate when the control
needs their data. Following this programming style, I would imagine
people composing the Page controls in the constructor setting the
DataProvider and thats it.
For example you could have a Cayenne SelectQueryDataProvider which
implements the DataProvider interface.
public CustomersPage() {
Table table = new Table("table");
table.addColumn(new Column('"firstName");
table.addColumn(new Column("lastName");
table.setDataProvider(new SelectQueryDataProvider
(Customer.class, "firstName"));
addControl(table);
}
This DataProvider would perform a SelectQuery(Customer.class) and
order by "firstName" when the table needs its data.
regards Malcolm Edgar
On Mon, Feb 22, 2010 at 9:51 AM, Malcolm Edgar<[email protected]> wrote:
+1 sounds like a good idea to me, I would like to see some design
concepts in the WIKI
regards Malcolm Edgar
On Sat, Feb 20, 2010 at 2:23 PM, Bob Schellink<[email protected]> wrote:
Hi all,
Currently the Table, Select and FormTable controls uses normal List objects
as data providers. While simple end easy to use it does lead to
inconsistencies, for example Table rowList can be set in onRender but Select
and FormTable need to be populated before onProcess.
How about we add a DataProvider interface that can be set for all three
components in the onInit event. The Control can then call this interface
when the data is needed. For Select and FormTable this will be during the
onProcess event, while Table will retrieve its data during rendering.
In addition this interface can act as a data proxy when paging. For example
the DataProvider can expose a getSize() method that returns 1000 while in
reality only 10 objects were retrieved.
Ajax can also benefit from a performance perspective. Imagine making an Ajax
request to a Page with multiple Select controls and FormTable. These
controls will be populated during the onInit event, but they won't be
processed because Ajax requests should only process the Control that was
interacted with.
kind regards
bob
