package com.bookshop.structural.facade;
import com.bookshop.domain.Customer;
import java.math.BigDecimal;
import java.util.concurrent.atomic.AtomicLong;
/** Subsystem 2: taking the money. */
public class PaymentService {
private final AtomicLong nextTransaction = new AtomicLong(1000);
public String charge(Customer customer, BigDecimal amount) {
return "txn-" + nextTransaction.incrementAndGet() + "-" + customer.id();
}
}