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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_customer_manager
#include <boost/contract.hpp>
#include <string>
#include <map>
#include <utility>
#include <cassert>
// Basic customer information.
struct customer_info {
friend class customer_manager;
typedef std::string identifier;
identifier id;
explicit customer_info(identifier const& _id) :
id(_id), name_(), address_(), birthday_() {}
private:
std::string name_;
std::string address_;
std::string birthday_;
};
// Manage customers.
class customer_manager {
friend class boost::contract::access;
void invariant() const {
BOOST_CONTRACT_ASSERT(count() >= 0); // Non-negative count.
}
public:
/* Creation */
customer_manager() {
// Check invariants.
boost::contract::check c = boost::contract::constructor(this);
}
virtual ~customer_manager() {
// Check invariants.
boost::contract::check c = boost::contract::destructor(this);
}
/* Basic Queries */
int count() const {
// Check invariants.
boost::contract::check c = boost::contract::public_function(this);
return customers_.size();
}
bool id_active(customer_info::identifier const& id) const {
// Check invariants.
boost::contract::check c = boost::contract::public_function(this);
return customers_.find(id) != customers_.cend();
}
/* Derived Queries */
std::string const& name_for(customer_info::identifier const& id) const {
boost::contract::check c = boost::contract::public_function(this)
.precondition([&] {
BOOST_CONTRACT_ASSERT(id_active(id)); // Active.
})
;
// Find != end because of preconditions (no defensive programming).
return customers_.find(id)->second.name_;
}
/* Commands */
void add(customer_info const& info) {
boost::contract::old_ptr<int> old_count = BOOST_CONTRACT_OLDOF(count());
boost::contract::check c = boost::contract::public_function(this)
.precondition([&] {
// Not already active.
BOOST_CONTRACT_ASSERT(!id_active(info.id));
})
.postcondition([&] {
BOOST_CONTRACT_ASSERT(count() == *old_count + 1); // Count inc.
BOOST_CONTRACT_ASSERT(id_active(info.id)); // Activated.
})
;
customers_.insert(std::make_pair(info.id, customer(info)));
}
void set_name(customer_info::identifier const& id,
std::string const& name) {
boost::contract::check c = boost::contract::public_function(this)
.precondition([&] {
BOOST_CONTRACT_ASSERT(id_active(id)); // Already active.
})
.postcondition([&] {
BOOST_CONTRACT_ASSERT(name_for(id) == name); // Name set.
})
;
// Find != end because of precondition (no defensive programming).
customers_.find(id)->second.name_ = name;
}
private:
class agent {}; // Customer agent.
struct customer : customer_info {
agent managing_agent;
std::string last_contact;
explicit customer(customer_info const& info) : customer_info(info),
managing_agent(), last_contact() {}
};
std::map<customer_info::identifier, customer> customers_;
};
int main() {
customer_manager m;
customer_info const js("john_smith_123");
m.add(js);
m.set_name(js.id, "John Smith");
assert(m.name_for(js.id) == "John Smith");
assert(m.count() == 1);
assert(m.id_active(js.id));
return 0;
}
//]
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