Fraud Identifier

This program reads Credit Card transactions from a CSV file and identifies whether any credit card numbers are fraudulent as per below criteria.

Criteria

The total transaction amount on a day is greater than the given threshold value.

Example

Credit Card CC0001 total transaction value > 50 on a given date, then CC0001 will be displayed in the output.

Valid CSV Sample Data

Only non-empty data will be considered, and the date format matches to ISO standard.

Sample test data file is present in src/test/resources/testData.csv

CCNumber	TransactionDate	Amount
CC0001	2020-12-16T10:50:00	10.00
CC0002	2020-12-16T10:50:00	15.50
CC0003	2020-12-16T10:50:00	23.70
CC0004	2020-12-16T10:50:00	43
CC0004	2020-12-16T10:50:10	125.74

Build

• Clone the repository
• Open terminal/command prompt and navigate to the FraudIdentifier directory
• Run mvn clean install command in terminal to build the Jar
• This will download dependencies and generate a Jar file in the target folder

Note: On macOS the built Jar may require copying to another directory

Test

Valid Input

Param	Type	Position	Required
Threshold Amount	Decimal	0	Yes
Path to CSV File	String	1	Yes
Transaction Date	Date in ISO format (YYYY-MM-dd)	2	Optional (Default today will be used)
Show CSV errors	Boolean	3	Optional (Default false)

• Open terminal/command prompt and navigate to the directory where the Jar file has been generated in the build step
• Run following command with valid parameters

java -jar FraudIdentifier-1.0.jar [Threshold Amount] [Path to CSV File] [Transaction Date] [Show Errors]

Tools and Libraries

Library	Purpose
Lombok	Generates setter, getter, builder for an annotated class
JUnit	Unit testing

Known Issue

• CSV data volume is limited to allocated Heap memory. If you plan to search on a large volume it is recommended to increase the JVM heap memory. Reference: https://docs.oracle.com/cd/E21764_01/web.1111/e13814/jvm_tuning.htm#PERFM157

  https://stackoverflow.com/questions/6452765/how-to-increase-heap-size-of-jvm

Area of Improvements

• Implementing a rule engine will allow defining business rules
• Implementing caching will improve search functionality
• Large volume can be handled efficiently using MapDB or similar library. https://github.com/jankotek/MapDB