Feat/idr rate aggregator

[FarizMR]

IDR Rate Aggregator

A Spring Boot REST API that fetches and serves IDR exchange rate data from the Frankfurter API.

Setup & Run

Prerequisites

• Java 21+
• Maven

Run the application

./mvnw spring-boot:run

Run tests

./mvnw test

Endpoint Usage

Base URL: http://localhost:8080

# Latest IDR rates
curl http://localhost:8080/api/finance/data/latest_idr_rates

# Historical IDR/USD rates
curl http://localhost:8080/api/finance/data/historical_idr_usd

# Supported currencies
curl http://localhost:8080/api/finance/data/supported_currencies

Personalization Note

GitHub Username: FarizMR
Spread Factor: (763 % 1000) / 100_000.0 = 0.00763
Formula: USD_BuySpread_IDR = (1 / Rate_USD) * (1 + 0.00763)

Architectural Rationale

1. Strategy Pattern : Each resource type is handled by its own class. Adding a new resource only needs a new class, no changes to existing code. The controller picks the right handler from a map, no if/else needed.

2. FactoryBean : Keeps all WebClient setup (base URL, timeout) in one dedicated class instead of scattered across config.

3. ApplicationRunner : Runs after everything is ready, so all beans are available when data fetching starts.