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// Copyright (C) 2008-2018 Lorenzo Caminiti
// Distributed under the Boost Software License, Version 1.0 (see accompanying
// file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
//[mitchell02_courier
#include <boost/contract.hpp>
#include <string>
#include <cassert>
struct package {
double weight_kg;
std::string location;
double accepted_hour;
double delivered_hour;
explicit package(
double _weight_kg,
std::string const& _location = "",
double _accepted_hour = 0.0,
double _delivered_hour = 0.0
) :
weight_kg(_weight_kg),
location(_location),
accepted_hour(_accepted_hour),
delivered_hour(_delivered_hour)
{}
};
// Courier for package delivery.
class courier
#define BASES private boost::contract::constructor_precondition<courier>
: BASES
{
friend class boost::contract::access;
typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types;
#undef BASES
static void static_invariant() {
// Positive min. insurance.
BOOST_CONTRACT_ASSERT(min_insurance_usd >= 0.0);
}
void invariant() const {
// Above min. insurance.
BOOST_CONTRACT_ASSERT(insurance_cover_usd() >= min_insurance_usd);
}
public:
static double min_insurance_usd;
/* Creation */
// Create courier with specified insurance value.
explicit courier(double _insurance_cover_usd = min_insurance_usd) :
boost::contract::constructor_precondition<courier>([&] {
// Positive insurance.
BOOST_CONTRACT_ASSERT(_insurance_cover_usd >= 0.0);
}),
insurance_cover_usd_(_insurance_cover_usd)
{
// Check invariants.
boost::contract::check c = boost::contract::constructor(this);
}
// Destroy courier.
virtual ~courier() {
// Check invariants.
boost::contract::check c = boost::contract::destructor(this);
}
/* Queries */
// Return insurance cover.
double insurance_cover_usd() const {
// Check invariants.
boost::contract::check c = boost::contract::public_function(this);
return insurance_cover_usd_;
}
/* Commands */
// Deliver package to destination.
virtual void deliver(
package& package_delivery,
std::string const& destination,
boost::contract::virtual_* v = 0
) {
boost::contract::check c = boost::contract::public_function(v, this)
.precondition([&] {
// Within max weight of this delivery.
BOOST_CONTRACT_ASSERT(package_delivery.weight_kg < 5.0);
})
.postcondition([&] {
// Within max delivery type.
BOOST_CONTRACT_ASSERT(double(package_delivery.delivered_hour -
package_delivery.accepted_hour) <= 3.0);
// Delivered at destination.
BOOST_CONTRACT_ASSERT(package_delivery.location == destination);
})
;
package_delivery.location = destination;
// Delivery takes 2.5 hours.
package_delivery.delivered_hour = package_delivery.accepted_hour + 2.5;
}
private:
double insurance_cover_usd_;
};
double courier::min_insurance_usd = 10.0e+6;
// Different courier for package delivery.
class different_courier
#define BASES private boost::contract::constructor_precondition< \
different_courier>, public courier
: BASES
{
friend class boost::contract::access;
typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types; // Subcontracting.
#undef BASES
static void static_invariant() {
BOOST_CONTRACT_ASSERT( // Better insurance amount.
different_insurance_usd >= courier::min_insurance_usd);
}
void invariant() const {
// Above different insurance value.
BOOST_CONTRACT_ASSERT(insurance_cover_usd() >= different_insurance_usd);
}
BOOST_CONTRACT_OVERRIDE(deliver)
public:
static double different_insurance_usd;
/* Creation */
// Create courier with specified insurance value.
explicit different_courier(
double insurance_cover_usd = different_insurance_usd) :
boost::contract::constructor_precondition<different_courier>([&] {
// Positive insurance value.
BOOST_CONTRACT_ASSERT(insurance_cover_usd > 0.0);
}),
courier(insurance_cover_usd)
{
// Check invariants.
boost::contract::check c = boost::contract::constructor(this);
}
// Destroy courier.
virtual ~different_courier() {
// Check invariants.
boost::contract::check c = boost::contract::destructor(this);
}
/* Commands */
virtual void deliver(
package& package_delivery,
std::string const& destination,
boost::contract::virtual_* v = 0
) /* override */ {
boost::contract::check c = boost::contract::public_function<
override_deliver
>(v, &different_courier::deliver, this, package_delivery, destination)
.precondition([&] {
// Package can weight more (weaker precondition).
BOOST_CONTRACT_ASSERT(package_delivery.weight_kg <= 8.0);
})
.postcondition([&] {
// Faster delivery (stronger postcondition).
BOOST_CONTRACT_ASSERT(double(package_delivery.delivered_hour -
package_delivery.accepted_hour) <= 2.0);
// Inherited "delivery at destination" postcondition.
})
;
package_delivery.location = destination;
// Delivery takes 0.5 hours.
package_delivery.delivered_hour = package_delivery.accepted_hour + 0.5;
}
};
double different_courier::different_insurance_usd = 20.0e+6;
int main() {
package cups(3.6, "store");
courier c;
c.deliver(cups, "home");
assert(cups.location == "home");
package desk(7.2, "store");
different_courier dc;
dc.deliver(desk, "office");
assert(desk.location == "office");
return 0;
}
//]
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