usedatabase3.cpp

来自「Thinking in c++ 2nd edition,c++编程思想（第2版）」· C++ 代码 · 共 32 行

//: C09:UseDatabase3.cpp
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// Tests a parameterized "mixin" class.
#include <cassert>
#include "Countable.h"
#include "DBConnection2.h"

class DBClient {
  DBConnection<Countable>* db;
public:
  DBClient(DBConnection<Countable>* dbCon) {
    db = dbCon;
    db->attach();
  }
  ~DBClient() { db->detach(); }
};

int main() {
  DBConnection<Countable>* db =
    DBConnection<Countable>::create("MyDatabase");
  assert(db->refCount() == 1);
  DBClient c1(db);
  assert(db->refCount() == 2);
  DBClient c2(db);
  assert(db->refCount() == 3);
  db->detach();
  assert(db->refCount() == 2);
} ///:~