This is a Java/Maven project that implements a service for validating customer statement transactions based on the transaction references ID and ending balance.

Some notes:

• if the request json does not have all the required fields(or field name mismatches), the service produce BAD_REQUEST response similar to json parsing problems. we could change this easily.
• on duplicate reference, id the service response with current record value(not the previous record with the same transaction id) based on assignment document

git clone "https://github.com/mohsenV1980/CustomerStatementProcessor.git" .

mvn test

mvn spring-boot:run

server starts at default port (8080). Make a post call to 'http://localhost:8080/` from postman(or any other way) with request type as JSON. Here is an example valid JSON request body:

{
"Transaction reference":"1",
"Account number": "TG6667xdWW",
"Start Balance": "0.0",
"Mutation" : "+90.0",
"Description" : "testing",
"End Balance" : "+90.0"
}

When RestController get a Post request,it retrieve the CustomerRecord from request body. After that it check different validation methods from Statement Processor Service and create a final HTTP response based on service response.

The Code consists of different Main parts:

• StatementProcessorController class:
  It is the RestController class and have just a method for processing post requests and return appropriate HTTP Response: processStatement

• StatementProcessorService class:
  It is a Service class that do the main logic of the service for checking different validation & creating the appropriate response

• StatementProcessorRepository class:
  It is a custom Repository class that work with data store(ArrayList for now) . it has methods for adding record and checking for duplications.

• RestExceptionHandler class:
  It is a Exception Handler Class. it has two methods:handleHttpMessageNotReadable for handling BAD_REQUEST and exception for all other exceptions.

Also There are 5 Other classes for Data Types:

• CustomerRecord class: for storing Customer Records.
• ErrorRecord class: for storing Different Response Errors.
• StatementResponse class: for final response of processed statement.
• InvalidCustomerRecordException class: Custom Exception for finding invalid Customer Records .

• CustomerStatementProcessorLogicTests class: this class is for Unit Testing. it has 5 different tests.
• CustomerStatementProcessorIntegrationTests class: this class is for Integration Testing. it has 2 different tests.