CORBA AMI call not producing callback? - c++

Question

I'm modifying the stock quoter example from the wustl CORBA release. The assignment is to implement a reply handler for the StockFactory class that handles calls to get_stock()
Here's my FactoryHandler implementation:
FactoryHandler_i.h:
#ifndef TAO_TUTORIALS_QUOTER_AMI_CLIENT_FACTORYHANDLER_I_H
#define TAO_TUTORIALS_QUOTER_AMI_CLIENT_FACTORYHANDLER_I_H
#include "QuoterS.h"
class Stock_Factory_Handler_i : public POA_Quoter::AMI_Stock_FactoryHandler
{
public:
Stock_Factory_Handler_i (int *response_count, ::Quoter::Stock_var& result);
void get_stock (::Quoter::Stock_ptr ami_return_val);
void get_stock_excep (::Messaging::ExceptionHolder * excep_holder);
private:
int *response_count_;
::Quoter::Stock_var& result_;
};
#endif /* TAO_TUTORIALS_QUOTER_AMI_CLIENT_HANDLER_I_H */
FactoryHandler_i.cpp:
#include "FactoryHandler_i.h"
#include "ace/streams.h"
Stock_Factory_Handler_i::
Stock_Factory_Handler_i (int *response_count, ::Quoter::Stock_var& result)
: response_count_ (response_count), result_ (result)
{
}
void
Stock_Factory_Handler_i::get_stock (::Quoter::Stock_ptr ami_return_val)
{
cout << "storing result" << endl;
result_ = ami_return_val;
(*this->response_count_)++;
}
void
Stock_Factory_Handler_i::get_stock_excep (::Messaging::ExceptionHolder * excep_holder)
{
// We ignore the exception, but this counts as a response, otherwise
// the application would not finish.
cerr << "Exception raised while getting stock"
<< endl;
(*this->response_count_)++;
}
And the client.cpp, from just before the part where changes have been made:
// ...
// Create and activate the handler...
int response_count = 0;
Single_Query_Stock_Handler_i handler_i (&response_count);
Quoter::AMI_Single_Query_StockHandler_var handler =
handler_i._this ();
// Create and activate the factory handler...
Quoter::Stock_var result;
Stock_Factory_Handler_i factory_handler_i (&response_count, result);
Quoter::AMI_Stock_FactoryHandler_var factory_handler =
factory_handler_i._this();
// Send all the requests, careful with error handling
int request_count = 0;
for (int i = 2; i != argc+1; ++i) {
try {
// Get the stock object
cout << "looking up stock symbol " << argv[i] << endl;
factory->sendc_get_stock (factory_handler.in (), argv[i]);
sleep(3); // wait for a response
cout << "converting result" << endl;
Quoter::Single_Query_Stock_var stock =
Quoter::Single_Query_Stock::_narrow (result.in ());
cout << "checking result" << endl;
CORBA::Any any;
any <<= stock;
CORBA::TypeCode_var tc = any.type();
cout << tc->kind() << endl;
if (CORBA::is_nil (stock.in ())) {
cerr << "Cannot get single query interface for <"
<< argv[i] << ">" << endl;
continue;
}
cout << "reading result" << endl;
stock->sendc_get_price_and_names (handler.in ());
request_count++;
}
catch (Quoter::Invalid_Stock_Symbol &) {
cerr << "Invalid stock symbol <"
<< argv[i] << ">" << endl;
}
}
while (response_count < 2 * request_count // multiply by 2 because both handlers increment response_count
&& orb->work_pending ()) {
orb->perform_work ();
}
// ...
When running the client, the output is:
looking up stock symbol MSFT
converting result
checking result
14
Cannot get single query interface for <MSFT>
(The 14 is the typecode for Stock, that's only for debugging)
Notably missing from the above is the "storing result" message that's supposed to be printed in the FactoryHandler's get_stock() callback method. I'm at a loss as to why, since the sendc_get_stock() method doesn't produce any (immediate) errors and is basically just a copy of the StockHandler's code, and from there it's the responsibility of the AMI/ORB interface to make the callback. But the original example (with a StockHandler only) works fine.
What am I doing wrong (and how do I fix it)?
EDIT: another bit of information: on the server side, StockFactory's get_stock() method does get called.

Answer 1

Sorry, I've no aswer for you. But a hint, ask your question at TOA's maling list at http://www.cs.wustl.edu/~schmidt/ACE-mail.html
HTH

Answer 2

I think that your problem is that work_pending returns true only if the ORB has immediate work to do, so it returns false in the time after your client sent his request and before the server sends his reply.
To validate that, simply remove the && orb->work_pending() condition from the loop, and use the version of perform_work that takes a timeout argument.