* - SourceAccount (behaviour)
* - DestinationAccount (behaviour)
* - AccountStateTemplate (state)
*/
public static void main(String... args) {
SourceAccount sourceAccount = Account.balance(1000).asSourceAccount();
DestinationAccount destinationAccount = Account.balance(100).asDestinationAccount();
System.out.println("=== before transaction ===");
System.out.println(sourceAccount);
System.out.println(destinationAccount);
System.out.println("\n=== transfer 400 ===");
sourceAccount.transferTo(destinationAccount, 400);
System.out.println("\n=== after transaction ===");
System.out.println(sourceAccount);
System.out.println(destinationAccount);
}