namespace libt2n
{
+/** @brief provide access to client_connection singletons and call-handling function
+
+ This is an abstact base class for use with T2nSingletonWrapper. It provides access
+ to the singleton-client_connection and offers a handle-method which is used for
+ every call to a method on a t2n-server.
+*/
class ConnectionWrapper
{
+ private:
+ long long command_timeout_usec;
+ long long hello_timeout_usec;
+
+ protected:
+ log_level_values log_level;
+ std::ostream *logstream;
+ void set_logging_on_connection(client_connection& c);
+
public:
+ ConnectionWrapper()
+ : log_level(none), logstream(NULL),
+ command_timeout_usec(command_client::command_timeout_usec_default),
+ hello_timeout_usec(command_client::hello_timeout_usec_default)
+ { }
+ virtual ~ConnectionWrapper()
+ { }
+
+ /** @brief return active connection, create new one if not existing
+
+ Return a pointer to an active client_connection. Use detail-data
+ stored within the derived class to create a new connection if needed,
+ otherwise return an alredy active connection. The derived class has
+ to take care of destroying the connection when not needed anymore.
+ */
virtual client_connection* get_connection()=0;
- virtual long long get_command_timeout_usec(void)
- {
- return command_client::command_timeout_usec_default;
- }
+ /** @brief this function is called on every execution of a method on a server
- virtual long long get_hello_timeout_usec(void)
- {
- return command_client::hello_timeout_usec_default;
- }
+ @param stubBase pointer to the command_client executing the call
+ @param f boost::function object containing the method to call and all parameters
+ @retval true if the call was successful and the original return-value of the called function can be used
+ false if T2nSingletonWrapper has to create a return-value with the default-constructor
- virtual void handle(command_client* stubBase, boost::function< void() > f)
+ T2nSingletonWrapper will call this function on every execution of a server-side
+ method. This version will just call the function without any special treatment.
+ You can overload this function to implement different error handling strategies.
+ */
+ virtual bool handle(command_client* stubBase, boost::function< void() > f)
{
f();
+ return true;
}
- virtual ~ConnectionWrapper()
- { }
+ long long get_command_timeout_usec(void)
+ { return command_timeout_usec; }
+
+ void set_command_timeout_usec(long long _command_timeout_usec)
+ { command_timeout_usec=_command_timeout_usec; }
+
+ long long get_hello_timeout_usec(void)
+ { return hello_timeout_usec; }
+
+ void set_hello_timeout_usec(long long _hello_timeout_usec)
+ { hello_timeout_usec=_hello_timeout_usec; }
+
+ virtual void set_logging(std::ostream *_logstream, log_level_values _log_level);
+
+ std::ostream* get_logstream(log_level_values level);
};
// contains the internal stuff needed for T2nWrapper
static const char* NotInitializedMessage;
};
+/** @brief wrap calls to server-side-functions with different error-handling strategies
+
+ Template class to access a process-wide singleton server-connection and to wrap all
+ calls using this connection with an error-handling strategy (e.g. to reconnect when
+ the connection broke). The source looks very complicated due to heavy use of templates,
+ look at the 3rd codegen example to see how to use it.
+
+ @par Example
+ Calling remote methods is usually done via t2n_exec, this saves you from always
+ specifying which T2nSingletonWrapper-template to use when calling T2nSingletonWrapper::exec
+ @code
+ t2n_exec(&cmd_group_t2nexample_client::testfunc)("the answer is %d",42)
+ @endcode
+*/
template< class Client >
class T2nSingletonWrapper : public T2nSingletonWrapperMessages
{
static std::auto_ptr<T2nSingletonWrapper> SingletonObject;
static std::auto_ptr<ConnectionWrapper> WrappedConnection;
+ /// @cond
// create a prep-method for each possible number of parameters
#define _GEN_ARG(z,n,d) Arg ## n arg ##n
#define _GEN_PREP(z,n,d) \
#undef _GEN_PREP
#undef _GEN_ARG
+ /// @endcond
T2nSingletonWrapper(std::auto_ptr<Client> stub)
{
if (WrappedConnection.get() == NULL)
throw std::logic_error(NotInitializedMessage);
- std::auto_ptr<Client> stub(new Client(*(WrappedConnection->get_connection()),
+ std::auto_ptr<Client> stub(new Client(WrappedConnection->get_connection(),
WrappedConnection->get_command_timeout_usec(),
WrappedConnection->get_hello_timeout_usec()));
ensure_singleton_there();
typename detail::TypeWrap<R>::type result;
+
+ // bind our Client-object and the local result
detail::Call<R> call( boost::bind( f, SingletonObject->Stub.get()), result );
- WrappedConnection->handle(SingletonObject->Stub.get(),call);
+
+ // let the wrapper-handler call the fully-bound function
+ if (!WrappedConnection->handle(SingletonObject->Stub.get(),call))
+ {
+ // create an result with default-constructor if the handler could not
+ // successfully do a call but no exception occured
+ result=typename detail::TypeWrap<R>::type();
+ }
return result;
}
public:
+ /** @brief tell the wrapper which connection to use
+ @param wrappedConnection the connection to establish when needed
+ */
static void set_connection(std::auto_ptr<ConnectionWrapper> wrappedConnection)
{
WrappedConnection=wrappedConnection;
if (SingletonObject.get() != NULL)
SingletonObject.reset();
}
- static ConnectionWrapper* get_connection(void)
+
+ /// return a pointer to the ConnectionWrapper currently in use
+ static ConnectionWrapper* get_connection_wrapper(void)
{ return WrappedConnection.get(); }
+ /// manually establish the connection without actually executing a call
static void ensure_singleton_there(void)
{
if (SingletonObject.get() == NULL)
init();
}
+ /// @cond
// create an exec-method for each possible number of parameters
#define _GEN_PLACEHOLDER(z,n,d) BOOST_PP_CAT(_,BOOST_PP_ADD(n,1))
#define _GEN_EXEC(z,n,d) \
#undef _GEN_EXEC
#undef _GEN_PLACEHOLDER
+ /// @endcond
};
+/// @cond
// create an t2n_exec-method for each possible number of parameters
#define _GEN_EXEC(z,n,d) \
template< class Client, typename R BOOST_PP_COMMA_IF(n) BOOST_PP_ENUM_PARAMS(n,typename Arg) > \
#undef _GEN_EXEC
#undef _GEN_PLACEHOLDER
+/// @endcond
}
#endif
git://developer.intra2net.com / libt2n / blobdiff