Hi Arul,
Yes and no. Yes. this is the way you set up RPC services client side,
but no, you do not necessarily have to have dozens of separate
callbacks, one for every single use case.
For example, here you have two methods that both return vectors of
accounts. You can merge them into a single RPC service method (thereby
cutting out half the tedious callback code) using a variant of the
Command pattern. For example:
public class AccountsCommand implements Serializable {
enum Operation {available, selected, ....,etc};
private Operation op; // best made immutable
private Vector<Account> accounts = new Vector<Account>();
// constructors, getters, setters, etc
}
You set the op and dispatch one of these to a single RPC service and
the RPC service returns the same object that now contains the results
e.g.
public interface AccountsService extends RemoteService {
AccountsCommand getAccounts(AccountsCommand command);
}
This is particularly convenient with enums because you can use a
switch statement in the (now) single callback to call the right
methods client side to control the UI, e,g,
public void onSuccess(AccountsCommand command) {
Command.Operation operation = command.getOperation();
switch (operation) {
case available: {doSomething(command.getAccounts
());break;}
case selected: {doSomethingElse(command.getAccounts
());break;}
//etc
}
");
which I think is quite neat and readable. You can also easily add
additional fields to AccountsCommand that might become necessary/
desirable without altering the RPC infrastructure code at all, and
also any useful utility methods for manipulating lists of accounts
(sorting for example). I like this approach because I think it
maintains a strong business focus around a group of related use cases
at the same time as simplifying the tedious RPC infrastructure code.
regards
gregor
On Dec 17, 2:17 pm, Arul <[email protected]> wrote:
> Hi,
> I written two business method inside service class.
> When I call these two methods inside client class, I have to write two
> seperate block containing onSuccess, onFailure methods for each of the
> business method in service class.
>
> For Example see my service class below
> ------------------------------------------------------------------------------------------------------
> public interface AccountsService extends RemoteService {
> Vector getAvailbleAccounts();
> Vector getSelectedAccounts();}
>
> ------------------------------------------------------------------------------------------------------
>
> Please find below my implementation (client) class for above two
> methods
> -----------------------------------------------------------------------------------------------------------------------------
> AsyncCallback<Vector> callback = new AsyncCallback<Vector>() {
> public void onFailure(Throwable caught) {
> System.out.println("Inside getAvailbleAccounts Error ");
>
> }
>
> public void onSuccess(Vector result) {
> System.out.println("Inside getAvailbleAccounts On Success ");
> };
> accountServiceSvc.getAvailbleAccounts(callback);
>
> AsyncCallback<Vector> callback1 = new AsyncCallback<Vector>() {
> public void onFailure(Throwable caught) {
> System.out.println("Inside getSelectedAccounts Error ");
> }
>
> public void onSuccess(Vector result) {
> System.out.println("Inside getSelectedAccounts On Success
> ");
> }
> };
> accountServiceSvc.getSelectedAccounts(callback1);
> -----------------------------------------------------------------------------------------------------------------------------
>
> Is this the way of writting blocks for every business method in GWT
> RPC?
>
> Thanks
> Arul
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