ME Bank Coding Challenge

Java8

Scenario As a user I enter the following input :

accountId: ACC334455
from: 20/10/2018 12:00:00
to: 20/10/2018 19:00:00

Acceptance Criteria :

The output should be:
Relative balance for the period is: -$25.00
Number of transactions included is: 1 

Given this CSV input :

transactionId, fromAccountId, toAccountId, createdAt, amount, transactionType, relatedTransaction
TX10001, ACC334455, ACC778899, 20/10/2018 12:47:55, 25.00, PAYMENT
TX10002, ACC334455, ACC998877, 20/10/2018 17:33:43, 10.50, PAYMENT
TX10003, ACC998877, ACC778899, 20/10/2018 18:00:00, 5.00, PAYMENT
TX10004, ACC334455, ACC998877, 20/10/2018 19:45:00, 10.50, REVERSAL, TX10002
TX10005, ACC334455, ACC778899, 21/10/2018 09:30:00, 7.25, PAYMENT

Assumptions

1. Account relative balance means the end result of processing ALL transactions for the time period entered, not just the accountId in question.
2. Reversals are processed first, which removes TX10002 from the list. it is never processed.
3. It is possible to have two unrelated transactions act as third party to an account relative balance, ie. The time frame must process all accounts, regardless of the user selected account.
4. The Number of transactions included reported is adjusted to list the number of transactions matching either the to or from account selected by the user.

Technical note

It may be slightly over complicating processing, however I believe for this fairly simple system to perform with relative consistency, it needs to process all payments, regardless of the accounts, in specified date range period, for the reflected account to have balance integrity.

That is unreleated accounts to what the user has selected, can and will given multiple payments, have direct result on the selected account.

Impacted account balances 3, transactions processed 2, reported number of transactions 1 :

[Account{accountId='ACC334455', balance=-25.00}, 
 Account{accountId='ACC778899', balance=30.00}, 
 Account{accountId='ACC998877', balance=-5.00}]

The Acceptance Criteria indicates the output should say Number of transactions included is: 1. I am deducing that this number is the number of transactions impacting ACC334455 in the scenerio provided, out of possibly many more transactions processed?

Running unit tests

gradlew test

Running through gradle

gradlew run --console=plain

Running from the jar

gradlew build jar
java -jar libs\challenge-1.0-SNAPSHOT.jar