afterPayCodingExercise

AfterPay Coding Exercise

Languages and Tools

• Java
• Gradle
• JUnit

Info

• Expecting Java , Gradle
• Tested it on MacOS
• Gradle 6.3
• JVM: 13.0.2 (Oracle Corporation 13.0.2+8)
• src/main/resources has the input files

Linting

• google-java-format-gradle-plugin

Execute the task googleJavaFormat to format all *.java files in the project ./gradlew goJF

Execute the task verifyGoogleJavaFormat to verify that all *.java files are formatted properly ./gradlew verGJF

Concepts

• Using HashMap to store transactions for a specified hashed Credit Card .
• Go with Concrete classes , until there is a requirement to extract stuff into interfaces. - Dependency Inversion

Assumptions

• InMemory Operations
• No TimeZone Conversions required
• Data provided is valid.
• Sliding 24hr window is ongoing i.e. specified date and time onward

To Run the program

• ./gradlew run
• Check example.log for the logs

To Run the tests

-- ./gradlew clean test -- Reports : at relative path build/reports/tests/test/index.html -- CC with transactions under the threshold -- CC with transactions over the threshold

Drawbacks of the Solution in its current form

• Have introduced a bit more complexity than required , inorder to make the solution extensible.
• Need to figure out how to improve the complexity in TransactionValidator from O(n*m)
• Need to add exception handling. (Time Constraint)

Some resources used

-- https://stackoverflow.com/questions/50368493/how-to-parse-yyyy-mm-ddthhmmss-sssxxx-date-format-to-simple-in-androidclea