Aria  2.8.0
functorExample.cpp

Illustrates the use of functors

See also
Functors in the ARIA overview
/*
Adept MobileRobots Robotics Interface for Applications (ARIA)
Copyright (C) 2004, 2005 ActivMedia Robotics LLC
Copyright (C) 2006, 2007, 2008, 2009, 2010 MobileRobots Inc.
Copyright (C) 2011, 2012, 2013 Adept Technology
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
If you wish to redistribute ARIA under different terms, contact
Adept MobileRobots for information about a commercial version of ARIA at
robots@mobilerobots.com or
Adept MobileRobots, 10 Columbia Drive, Amherst, NH 03031; +1-603-881-7960
*/
#include <string>
#include "Aria.h"
/*
This is a class that has some callback methods. Functors which refer to these
callbacks will be passed to the DriverClass.
*/
class CallbackContainer
{
public:
void callback1();
void callback2(int i);
bool callback3(const char *str);
};
void CallbackContainer::callback1()
{
printf("CallbackContainer::callback1 called.\n");
}
void CallbackContainer::callback2(int i)
{
printf("CallbackContainer::callback2 called with argument of '%d'\n", i);
}
bool CallbackContainer::callback3(const char *str)
{
printf("CallbackContainer::callback3 called with argument of '%s'.\n", str);
return(true);
}
/*
* Functors can also invoke global functions.
*/
void globalCallback()
{
printf("globalCallback() called.\n");
}
/*
This is a "driver" class. It takes three functors of different types and
will invoke the three functors. This is a typical use of
functors: to pass information or event notifications between loosely
coupled objects.
*/
class DriverClass
{
public:
void invokeFunctors();
void setCallback1(ArFunctor *func) {myFunc1=func;}
void setCallback2(ArFunctor1<int> *func) {myFunc2=func;}
void setCallback3(ArRetFunctor1<bool, const char *> *func) {myFunc3=func;}
protected:
ArFunctor *myFunc1;
ArFunctor1<int> *myFunc2;
};
void DriverClass::invokeFunctors()
{
bool ret;
printf("Invoking functor1... ");
myFunc1->invoke();
printf("Invoking functor2... ");
myFunc2->invoke(23);
/*
For functors with return values, use invorkeR() instead of invoke()
to get the return value. The invoke() function can also be used to invoke
the functor, but the return value is lost. (And is a possible source
of memory leaks if you were supposed to free a pointer returned.)
*/
printf("Invoking functor3... ");
ret=myFunc3->invokeR("This is a string argument");
if (ret)
printf("\t-> functor3 returned 'true'\n");
else
printf("\t-> functor3 returned 'false'\n");
}
int main()
{
CallbackContainer cb;
DriverClass driver;
ArFunctorC<CallbackContainer> functor1(cb, &CallbackContainer::callback1);
ArFunctor1C<CallbackContainer, int> functor2(cb, &CallbackContainer::callback2);
functor3(cb, &CallbackContainer::callback3);
driver.setCallback1(&functor1);
driver.setCallback2(&functor2);
driver.setCallback3(&functor3);
driver.invokeFunctors();
/* You can make functors that target global functions too. */
ArGlobalFunctor globalFunctor(&globalCallback);
printf("Invoking globalFunctor... ");
globalFunctor.invoke();
/* You can also include the values of arguments in an ArFunctor object, if you
* want to use the same value in every invocation of the functor.
*/
ArFunctor1C<CallbackContainer, int> functor4(cb, &CallbackContainer::callback2, 42);
printf("Invoking functor with constant argument... ");
functor4.invoke();
/* Functors can be downcast to parent interface classes, as long as their invocation
* does not require arguments.
*/
ArFunctor* baseFunctor = &functor4;
printf("Invoking downcast functor... ");
baseFunctor->invoke();
return(0);
}