e-Wallet Transaction System

This is a very basic e-Wallet Transaction System that provides small features revolving around user's wallets.

Functional Requirements

• Create a wallet (with phone number and name)
• Create a debit transaction (with checks on maximum debit amount, minimum wallet balance)
• Create a credit transaction
• Get current wallet status (balance, list of transactions etc.)

System Validations

• Minimum wallet balance to be maintained, driven via configuration.
• A maximum cap on a single debit request, driven via configuration.
• Mobile number should be exactly 10 digits long.
• First name should contain atleast 3 characters.
• Debit & credit amount cannot be negative.

Non-Functional Requirements

• Handle simultaneous debits, honouring the first request and asking the user to re-try on the second request.

Execution Details

• /src/main/java/com/ewallet contains all the solution files.
• /src/main/java/resources contains the resources files - application.properties
• gradle clean build to create an executable JAR.
• java -jar build/libs/e-wallet-1.0.jar to run the JAR.

Config Properties:

• Minimum wallet balance to maintain: limits.min-wallet-balance (default = 100)
• Maximum debit limit for users: limits.max-debit (default = 1000)

cURL Requests

• Create Wallet:

curl --request POST \
  --url http://localhost:8080/api/v1/wallet/create \
  --header 'Content-Type: application/json' \
  --data '{
	"phoneNo" : "9632211999",
	"firstName": "Karan",
	"lastName": "Uppal"
}'

• Get Wallet Status (Balance, Transactions etc.):

curl --request GET \
  --url http://localhost:8080/api/v1/wallet/status/9632211999 \
  --header 'Content-Type: application/json'

• Credit Wallet:

curl --request POST \
  --url http://localhost:8080/api/v1/transact/credit \
  --header 'Content-Type: application/json' \
  --data '{
	"phoneNo" : "9632211999",
	"amount": 500
}'

• Debit Wallet:

curl --request POST \
  --url http://localhost:8080/api/v1/transact/debit \
  --header 'Content-Type: application/json' \
  --data '{
	"phoneNo" : "9632211999",
	"amount": 100
}'

Demo Response

• Create Wallet, Credit 500, Debit 100, Check Status:
• Create Wallet, Credit 500, Debit 100, (10s sleep), Debit 100:
• Create Wallet, Debit 100: