AX1818 / ap-anti-fraud

Solution

The interface com.ap.creditcard.AntiFraud is designed to provide a static method static List<String> filterFraudTransactions(final List<String> creditCardTransactions, LocalDate transactionDate, BigDecimal threshold) which can determine if a transaction is a fraud one by the specified transaction date and the threshold for that day.

This method uses the steam api in Java 8 to handle the transaction list. It has four steps as below:

1. convert transaction literal data into instances of com.ap.creditcard.Transaction class.
2. Filter out all the transaction data by comparing their transaction date with the specified date.
3. Total up the transaction amount by the transaction number via a <transaction no, total amount> map.
4. streaming the map entries to collect the keys, i.e. transaction numbers into a list and then return it.

Run tests

The tests are in com.ap.creditcard.AntiFraudTest class. To run the tests, just execute the maven command:

mvn test