Hey all,
I was looking for a solution to the exception handling described above
and tried the technique suggested. However, when I implement the
exception in the onFailure method as shown, eclipse barfs and shows a
"unhandled exception type throwable" error at me. Same thing happens
when I try to compile anyway.
- I'm using GWT 1.5 and tried extending the exception with both
Exception as well as SerializationException
- Also, I'm implementing a fascade pattern as described in the GWT in
Action Book for the RPC calls.
Here's a scenario of what I'm trying
public class MyRPCException extends Exception
{
// same definition of exception as above really.
}
public interface MyRPCService
{
ArrayList<SomeType> load() throws MyRPCException;
}
public interface MyRPCServiceAsync
{
void load(AsyncCallback<ArrayList<SomeType>>);
}
public class MyRPCFascade
{
private MyRPCFascade() // singleton is used just didn't
bother inserting code here because i think its irrelevant to the
issue.
{
proxy = (MyRPCServiceAsync) GWT.create(MyRPCService.class);
ServiceDefTarget endPoint = (ServiceDefTarget) proxy;
endPoint.setServiceEntryPoint("/myRPCService");
}
public void load(AsyncCallback<ArrayList<SomeType>>)
{
proxy.load(callback);
}
}
--- Server side ----
public class MyRPCServiceImpl implements MyRPCService
{
public ArrayList<SomeType> load() throws MyRPCExecption
{
try {.....}
catch(SomeException e) { throw new MyRPCException(); }
}
}
----- Client Side ----
myRPCFascade.load(new SomeTypeCallback() )
class SomeTypeCallback implements AysncCallback<ArrayList<SomeType>>
{
public void onSuccess(ArrayList<SomeType> result)
{
// .... process result
}
public void onFailure(Throwable caught)
{
try
{
throw caught; // **** This is where
compilation Fails
}
catch(MyRPCException e)
{
Window.alert("DING");
}
}
}
Any ideas what I'm doing wrong?
Thanks
Suri
On Nov 26, 11:08 pm, satya <[email protected]> wrote:
> There is a SerializationException
>
> (public class SerializationException
> extends java.lang.Exception) in gwt1.5.
>
> SerializableException is depricated in 1.5
>
> I shall try your suggestion of extending theExceptionor use the
> SerilizationException and post the code here.
>
> Thank you both for your help,
> Appreciate it
> Satya
>
> On Nov 26, 12:54 pm, jossey <[email protected]> wrote:
>
> > I am sorry... my bad... I read it as SerializationException....
> > Looked at the SerializableException in gwt... it is just anException
> > implementing IsSerializable interface... so it all makes sense.
> > Thanks Ravi for clarifying.
>
> > BTW, in 1.5 gwt supports serialization of objects implementing
> > java.io.Serializable.
> > So just by extendingExceptionit would work.
>
> > Thanks again,
> > Jossey.
>
> > On Nov 26, 8:56 am, Ravi M <[email protected]> wrote:
>
> > > Jossey
>
> > > Quite the contrary, actually. I started off with a customexception
> > > which was merely a child class ofExceptionthat I intended to use in
> > > RPC calls (i.e. service methods throw it). This actually didn't work
> > > in the ways expected, i.e. when the server threw theexceptionI was
> > > unable to retrieve theexceptionmessage in the client, or find out
> > > what the cause was. Which is when some digging around revealed that if
> > > you want to send theexceptionover the wire, it has to be a GWT
> > > SerializableException.
>
> > > This is with 1.4.6x, of course this may have changed in 1.5.x, I am
> > > not sure.
>
> > > Ravi
>
> > > On Nov 26, 5:58 pm, jossey <[email protected]> wrote:
>
> > > > Hi,
> > > > Why are we extending SerializableException?
> > > > Is that because the starting example had it so?
> > > > I think it kinds of gives out a wrong message. ...
> > > > just extendsExceptionshould do.
>
> > > > not very relevant to the discussion.... anyways...
>
> > > > Jossey.
>
> > > > On Nov 25, 3:33 pm, Ravi M <[email protected]> wrote:
>
> > > > > Ah me. Step 1 should read:
>
> > > > > 1. Declare your RPCexceptionlike so:
>
> > > > > public class MyRPCException extends SerializableException {
> > > > > public MyRPCException() {
> > > > > super();
> > > > > }
>
> > > > > public MyRPCException(String message) {
> > > > > super(message);
> > > > > }
>
> > > > > //... other stuff?
>
> > > > > }
>
> > > > > On Nov 26, 1:32 am, Ravi M <[email protected]> wrote:
>
> > > > > > Satya,
>
> > > > > > The following should work.
>
> > > > > > 1. Declare your RPCexceptionlike so:
>
> > > > > > public class MyRPCException extends SerializableException {
> > > > > > public TrackerRPCException() {
> > > > > > super();
> > > > > > }
>
> > > > > > public MyRPCException(String message) {
> > > > > > super(message);
> > > > > > }
>
> > > > > > //... other stuff?
>
> > > > > > }
>
> > > > > > 2. Declare your service method like so:
>
> > > > > > public SomeReturnedObject myServiceMethod(...arguments...) throws
> > > > > > MyRPCException;
>
> > > > > > 3. Declare your async service method like so:
>
> > > > > > public void myServiceMethod(...arguments..., AsyncCallback
> > > > > > callback);
>
> > > > > > 4. The server side implementation of your service method may be like
> > > > > > so:
>
> > > > > > public SomeReturnedObject myServiceMethod(...arguments...)
> > > > > > throws
> > > > > > MyRPCException {
> > > > > > SomeReturnedObject ret = null;
> > > > > > try {
> > > > > > // Do stuff to "populate" ret. This stuff could
> > > > > > potentially fail.
> > > > > > } catch (SomeNonGWTSerializableServerSideException e) {
> > > > > > throw new MyRPCException("This is an error message that
> > > > > > may be appropriate to show in the UI: " + e.getMessage());
> > > > > > }
> > > > > > return ret;
> > > > > > }
>
> > > > > > 5. In your AsyncCallback in the client:
>
> > > > > > public void onSuccess(Object result) {
> > > > > > SomeReturnedObject foo = (SomeReturnedObject)
> > > > > > result;
> > > > > > // Happiness and tranquility reign supreme
> > > > > > };
>
> > > > > > public void onFailure(Throwableexception) {
> > > > > > try {
> > > > > > throwexception;
> > > > > > } catch (MyRPCException e) {
> > > > > > // Show the error message to the user,
> > > > > > // or handle however you want to.
> > > > > > }
> > > > > > };
>
> > > > > > This should work, there may be some overkill in this though. All
> > > > > > this
> > > > > > is GWT 1.4.6x, I'm not sure if any of this has changed in 1.5.x.
>
> > > > > > Hope this helps
>
> > > > > > Ravi
>
> > > > > > On Nov 26, 1:08 am, satya <[email protected]> wrote:
>
> > > > > > > Thank you very much,
> > > > > > > I guess i can return the String "IllegalDateRangeException" when
> > > > > > > throwing thatexceptionfrom my Service and check for that in my
> > > > > > > onFailure class.
>
> > > > > > > public void onFailure( Throwable caught )
> > > > > > > {
> > > > > > > if ( caught.getMessage().contains
> > > > > > > ( "IllegalDateRangeException" ) )
>
> > > > > > > //handle my class.
> > > > > > > }
>
> > > > > > > Thnak you,
> > > > > > > Satya
>
> > > > > > > On Nov 25, 1:38 pm, "olivier nouguier"
> > > > > > > <[email protected]>
> > > > > > > wrote:
>
> > > > > > > > On Tue, Nov 25, 2008 at 8:14 PM, satya <[email protected]>
> > > > > > > > wrote:
>
> > > > > > > > > Also
>
> > > > > > > > > when i call the actual method, does theexceptionget caught in
> > > > > > > > > the
> > > > > > > > > failure method or in my catch method?
>
> > > > > > > > > For example:
>
> > > > > > > > > AsyncCallback callBack = new AsyncCallback() {
> > > > > > > > > public void onFailure( Throwable caught )
> > > > > > > > > {
> > > > > > > > > //Is theexceptioncaught here?????
> > > > > > > > here !
> > > > > > > > > }
>
> > > > > > > > > public void onSuccess( Object result )
> > > > > > > > > {
>
> > > > > > > > > }
> > > > > > > > > try
> > > > > > > > > {
> > > > > > > > > createNewRuleService.createRule(
> > > > > > > > > screenType,
> > > > > > > > > eventRuleForm, callBack );
> > > > > > > > > }
> > > > > > > > > catch ( IllegalDateRangeException e )
> > > > > > > > > {
> > > > > > > > > //// or theexceptionis caught here?
>
> > > > > > > > > }
>
> > > > > > > > You should notice the differences between RemoteInterface and
> > > > > > > > its
> > > > > > > > Asyn counter part:
> > > > > > > > * return type: the asyn interface method doesn't have return
> > > > > > > > value
> > > > > > > > ===> it will be pass as parameter asynchronously in onSuccess
> > > > > > > > callback.
> > > > > > > > *exception: are not part of the async method ===> it will be
> > > > > > > > pass
> > > > > > > > as parameter asynchronously in onFailure callback.
>
> > > > > > > > > Thank you very much for your help. I appreciate it.
>
> > > > > > > > > Satya
>
> > > > > > > > > On Nov 25, 1:10 pm, satya <[email protected]> wrote:
> > > > > > > > >> How do i specify in the service signature that this is GWT
> > > > > > > > >> serializable?
>
> > > > > > > > >> my method signature looks like:
> > > > > > > > >> public String create(Rule rule) throws
> > > > > > > > >> IllegalDateRangeException;
>
> > > > > > > > >> On Nov 23, 5:23 am, "olivier nouguier"
> > > > > > > > >> <[email protected]>
> > > > > > > > >> wrote:
>
> > > > > > > > >> > On Sun, Nov 23, 2008 at 6:58 AM, satya
> > > > > > > > >> > <[email protected]> wrote:
>
> > > > > > > > >> > > Hi,
>
> > > > > > > > >> > > Can i pass exceptions between client and server.
> > > > > > > > >> > > Can i have an RPC serice with method that throw an user
> > > > > > > > >> > > defined
> > > > > > > > >> > >exceptionand handle thatexceptionin the client side?
>
> > > > > > > > >> > Yes as long as your exeption is declared in the Service
> > > > > > > > >> > Signature (to
> > > > > > > > >> > be declared as "GWT serialisable").
>
> > > > > > > > >> > > I created an userdefinedexception:
> > > > > > > > >> > > ------------------------------------------------------
> > > > > > > > >> > > public class IllegalDateRangeException extends
> > > > > > > > >> > > SerializationException
> > > > > > > > >> > > implements IsSerializable
> > > > > > > > >> > > {
> > > > > > > > >> > > private String errorMessage = null;
>
> > > > > > > > >> > > public IllegalDateRangeException ( String error )
> > > > > > > > >> > > {
> > > > > > > > >> > > errorMessage = error;
> > > > > > > > >> > > }
>
> > > > > > > > >> > > public String toString()
> > > > > > > > >> > > {
> > > > > > > > >> > > return "Exceptionoccurred: " + errorMessage;
> > > > > > > > >> > > }
>
> > > > > > > > >> > > public String getErrorMessage()
> > > > > > > > >> > > {
> > > > > > > > >> > > return errorMessage;
> > > > > > > > >> > > }
>
> > > > > > > > >> > > public void setErrorMessage( String errorMessage )
> > > > > > > > >> > > {
> > > > > > > > >> > > this.errorMessage = errorMessage;
> > > > > > > > >> > > }
>
> > > > > > > > >> > > }
>
> > > > > > > > >> > > and my RPC method throws thisexception:
> > > > > > > > >> > > ------------------------------------------------
> > > > > > > > >> > > public String create(Rule rule) throws
> > > > > > > > >> > > IllegalDateRangeException;
>
> > > > > > > > >> > > and i want to catch this
>
> ...
>
> read more »
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