C++ Store::getInventory方法代码示例

//---------------------------------------------------------------------------
// Perform
// Preconditions:	Movie exists, Movie Count is not 0, Customer doen't have 
//					the movie 
// Postconditions:	Customer has the movie, movie count is decremented
// Overrides Transactions virtual Perform. Before Performing the transaction
// the fucntion checks for validity. Then adds the movie to customer sets 
// performed variable to true and adds the transaction to the transaction
// list
//---------------------------------------------------------------------------
bool Borrow::Perform(Store& store)
{
	store.getInventory().Retrieve(*tempMovie, movie); 

	if (movie == NULL)
	{
		performed = false; 
		return false; 
	}

	else if (movie->getCount() < 1)
	{
		performed = false; 
		return false; 
	}

	else if (customer->HasMovie(movie))
	{
		performed = false;
		return false;
	}

	else if (!movie->DecrementCount())
		return false; 

	else
	{
		customer->AddMovie(movie); 
		performed = true; 
		customer->getTransactionList().Insert(this); 

		return true; 
	}
}

//--------------------------------Execute---------------------------------//
//this method performs the actions for the Borrow object, using the
//store as a parameter to access the inventory and alter accordingly
//it also uses the file stream to read in the information
//according to formatting specifications, setting it for this specified
//derived transaction class
bool Borrow::execute(ifstream& file, Store& st)
{
	int custIdx;
	file >> custIdx;
	Customer* cust = st.getCustomer(custIdx);
	//read the custtomer index and get the customer at that index
	//from the store, if the store doesn't have the customer at that
	//spot then the customer has not been created and we cannot do anything
	if (cust == NULL)
	{
		cout << "Invalid Customer ID. Transaction could not be executed.\n";
		//no need for clean up since Customer is still NULL
		return false;
	}
	else
	{
		char format;
		file >> format;
		//read in the format, the format is specified to only be DVDs
		if (format != 'D')
		{
			cout << "Invalid format. Transaction could not be executed.\n";
			//no need for clean up since Formaat is not dynamic
			return false;
		}
		else
		{
			char genre;
			file >> genre;
			//read in the genre and then use the stores movie factory
			//to create a temporary movie of this genre,
			//however, if the genre did not correspond to an appropriate
			//movie, return false
			Movie* tempMov = st.getMovieFact().createIt(genre);
			if (tempMov == NULL)
			{
				cout << "Invalid movie. Transaction could not be "
					<< "executed.\n";
				//no need for clean up since tempMov is still NULL
				return false;
			}
			else
			{
				//everything worked, now we try to set the data
				//from the format specifications of a borrow
				//movie, and if this didn't work, the movie was 
				//created so we must clean this up. otherwise, we try
				//to borrow the movie from the inventory
				if (!tempMov->readTrans(file))
				{
					delete tempMov;
					tempMov = NULL;
					return false;
				}
				else
				{
					Movie* mov = NULL;
					//use a movie locator and a movie return value
					//to try to borrow the movie from the stores
					//inventory, if the borrow couldn't occur
					//we must delete the temporary movie
					if (!st.getInventory().borrowMovie(mov, tempMov))
					{
						cout << "Invalid movie. Transaction could not be "
							<< "executed.\n";
						delete tempMov;
						tempMov = NULL;

						return false;
					}
					else
					{
						//otherwise everything has worked out so far
						//so we set the data of the borrow transaction
						//because we already know the movie
						//and the customer is accurate
						setData(cust, mov);
						//if we couldn't borrow we must clean up
						if (!cust->borrowMovie(mov))
						{
							cout << "Invalid movie." <<
								"Transaction could not be "
								<< "executed.\n";
							delete tempMov;
							tempMov = NULL;
							return false;
						}
						//otherwise everything worked out perfectly
						//so the data is set and the customer
						//adds this transaction to his/her trans hist
						//and clean up our temp mov
						cust->addTransaction(this);
						delete tempMov;
						tempMov = NULL;
//.........这里部分代码省略.........