Spring Boot Rest API that manages transactions information

Tech Stack

• IDE: IntelliJ IDEA Community Edition (2022.1.1)
• Java 17
  • Java Text Blocks
  • Switch Statement
• Spring Boot: 2.7.0
  • Spring Data
  • Spring DevTools
• MapStruct
• Lombok
• SpringDoc OpenApi
• Maven 3.8.4
• H2 Database

Prerequisites to test/run the application

• Java 17
• Maven 3.8.4

Updated Requirements

While I was developing this project, I had to update the requirements as I encountered some issues.

1. reference (optional): The transaction unique reference number in our system. If not present, the system will generate one. The reference number is the ID of the transaction, and it will ALWAYS be automatically generated by the system. If we allow the client to provide a reference number we may have inconsistency in our database or if the client provides an already existing reference in our database it will give an error back.

Run tests

You can use your favorite IDE to run the tests or use the following command:

mvn test

Run the application

1. Clone the repository
2. In the cloned folder repository, run the following command:

mvn spring-boot:run

Available endpoints

Since the project uses SpringDoc OpenApi, we can see the available endpoints at the following link:

http://localhost:8080/swagger-ui/index.html

Example of the first time you access Swagger UI

Examples to call the endpoints

You can use the HTTP client of your choice to call the endpoints. In the next examples I will use Postman to perform the requests.

Using the import feature of Postman you can import the OpenAPI definition from the following link: http://localhost:8080/v3/api-docs

Create a new transaction

• POST /api/v1/transactions

{
	"account_iban": "ES3730046235659186738712",
	"date": "2022-08-01T17:30:42.000Z",
	"amount": 68.18,
	"fee": 3.18,
	"description": "Restaurant payment"
}

Example calling POST /api/v1/transactions

Find transactions by account iban and sort by field and order

In order to have some data in our database when the application starts, I used a CommandLineRunner to create some transactions. The iban account that will be used to perform the filtering and sorting is: ES3730046235659186738712 You could also use the Create a new transaction endpoint to create as many transactions as you wish.

• GET /api/v1/transactions/search?account_iban=ES3730046235659186738712&sortField=amount&sortOrder=DESC

Example calling GET /api/v1/transactions/search

Transaction status

• POST /api/v1/transactions/status

Based on the following rules, you'll need to create a transaction per business rule and use the reference number you obtain from calling the endpoint Create a new transaction to obtain the status of the transaction.

Payload to call POST /api/v1/transactions/status

{
  "reference":"12345A",
  "channel":"CLIENT"
}

• reference (mandatory): The transaction reference number channel (optional): The type of the channel that is asking for the
• status. It can be any of these values: CLIENT, ATM, INTERNAL

Response:

{
  "reference":"12345A",
  "status":"PENDING",
  "amount":193.38,
  "fee":3.18
}

• reference: The transaction reference number
• status: The status of the transaction. It can be any of these values: PENDING, SETTLED, FUTURE, INVALID
• amount: the amount of the transaction
• fee: The fee applied to the transaction

Business Rules

A)

Given: A transaction that is not stored in our system
When: I check the status from any channel
Then: The system returns the status 'INVALID'

Example payload:

{
  "reference": "99463375-d63a-4176-aa03-14140adb1cb8",
  "channel": "INTERNAL"
}

Example response:

{
  "reference": "99463375-d63a-4176-aa03-14140adb1cb8",
  "status": "INVALID"
}

---

B)

First create the following transaction

Create a new transaction with the following payload:

{
  "account_iban": "ES3730046235659186738712",
  "date": "2021-06-01T17:30:42.000Z",
  "amount": 88.18,
  "fee": 3.18,
  "description": "Restaurant payment"
}

Given: A transaction that is stored in our system
When: I check the status from CLIENT or ATM channel
    And the transaction date is before today
Then: The system returns the status 'SETTLED'
    And the amount substracting the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "c7f778d2-faa5-4c48-a19b-4f3cc1350d39",
  "channel": "CLIENT"
}

Example response:

{
  "reference": "c7f778d2-faa5-4c48-a19b-4f3cc1350d39",
  "status": "SETTLED",
  "amount": 85.00
}

---

C)

Given: A transaction that is stored in our system
When: I check the status from INTERNAL channel
    And the transaction date is before today
Then: The system returns the status 'SETTLED'
    And the amount
    And the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "c7f778d2-faa5-4c48-a19b-4f3cc1350d39",
  "channel": "INTERNAL"
}

Example response:

{
  "reference": "c7f778d2-faa5-4c48-a19b-4f3cc1350d39",
  "status": "SETTLED",
  "amount": 88.18,
  "fee": 3.18
}

---

D)

First create the following transaction

Create a new transaction with the following payload:

MAKE SURE THE DATE IS FROM TODAY

{
  "account_iban": "ES3730046235659186738712",
  "date": "2022-06-01T17:30:42.000Z",
  "amount": 88.18,
  "fee": 3.18,
  "description": "Restaurant payment"
}

Given: A transaction that is stored in our system
When: I check the status from CLIENT or ATM channel
    And the transaction date is equals to today
Then: The system returns the status 'PENDING'
    And the amount substracting the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "7eebabc8-d6a1-4099-8f49-0ff7cff91d4c",
  "channel": "CLIENT"
}

Example response:

{
  "reference": "7eebabc8-d6a1-4099-8f49-0ff7cff91d4c",
  "status": "PENDING",
  "amount": 85.00
}

---

E)

Given: A transaction that is stored in our system
When: I check the status from INTERNAL channel
    And the transaction date is equals to today
Then: The system returns the status 'PENDING'
    And the amount
    And the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "7eebabc8-d6a1-4099-8f49-0ff7cff91d4c",
  "channel": "INTERNAL"
}

Example response:

{
  "reference": "7eebabc8-d6a1-4099-8f49-0ff7cff91d4c",
  "status": "PENDING",
  "amount": 88.18,
  "fee": 3.18
}

---

F)

First create the following transaction

Create a new transaction with the following payload:

{
  "account_iban": "ES3730046235659186738712",
  "date": "2023-08-01T17:30:42.000Z",
  "amount": 88.18,
  "fee": 3.18,
  "description": "Restaurant payment"
}

Given: A transaction that is stored in our system
When: I check the status from CLIENT channel
    And the transaction date is greater than today
Then: The system returns the status 'FUTURE'
    And the amount substracting the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "7eebabc8-d6a1-4099-8f49-0ff7cff91d4c",
  "channel": "CLIENT"
}

Example response:

{
  "reference": "614f8662-a874-47b5-be45-a0abcf66d819",
  "status": "FUTURE",
  "amount": 85.00
}

---

G)

Given: A transaction that is stored in our system
When: I check the status from ATM channel
    And the transaction date is greater than today
Then: The system returns the status 'PENDING'
    And the amount substracting the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "614f8662-a874-47b5-be45-a0abcf66d819",
  "channel": "ATM"
}

Example response:

{
  "reference": "614f8662-a874-47b5-be45-a0abcf66d819",
  "status": "PENDING",
  "amount": 85.00
}

---

H)

Given: A transaction that is stored in our system
When: I check the status from INTERNAL channel
    And the transaction date is greater than today
Then: The system returns the status 'FUTURE'
    And the amount
    And the fee

Example payload:

Using the reference obtained when calling the endpoint Create a new transaction

{
  "reference": "614f8662-a874-47b5-be45-a0abcf66d819",
  "channel": "INTERNAL"
}

Example response:

{
  "reference": "614f8662-a874-47b5-be45-a0abcf66d819",
  "status": "FUTURE",
  "amount": 88.18,
  "fee": 3.18
}