我试图理解面向切面编程（AOP），一些Qt代码会对我有所帮助。
以下是来自维基百科的示例代码（易于Qt/C++程序员阅读）：
void transfer(Account fromAcc, Account toAcc, int amount, User user, Logger logger)
throws Exception {
logger.info("transferring money...");
if (! checkUserPermission(user)){
logger.info("User has no permission.");
throw new UnauthorizedUserException();
}
if (fromAcc.getBalance() < amount) {
logger.info("Insufficient Funds, sorry :( ");
throw new InsufficientFundsException();
}
fromAcc.withdraw(amount);
toAcc.deposit(amount);
//get database connection
//save transactions
logger.info("Successful transaction. :) ");
}
然后就是"aspectized":
void transfer(Account fromAcc, Account toAcc, int amount) throws Exception {
if (fromAcc.getBalance() < amount) {
throw new InsufficientFundsException();
}
fromAcc.withdraw(amount);
toAcc.deposit(amount);
}
aspect Logger
{
void Bank.transfer(Account fromAcc, Account toAcc, int amount, User user, Logger logger)
{
logger.info("transferring money...");
}
void Bank.getMoneyBack(User user, int transactionId, Logger logger)
{
logger.info("User requested money back");
}
// other crosscutting code...
}