[feat]: Implement Caching for API Responses

[0PrashantYadav0]

Description

• Detailed Description:
  Repeated external API calls to Finnhub can lead to performance bottlenecks and trigger rate limiting. Caching the responses for a short period can significantly improve performance and reduce external API usage.
• How to Solve:
  1. Enable Caching in Spring Boot:
     Add @EnableCaching to your main application class.
  2. Annotate Service Methods:
     Use the @Cacheable annotation on methods like getStockPrice:

     @Cacheable("stockPrice")
     public String getStockPrice(String symbol) {
         // existing code
     }

  3. Configure a Cache Manager:
     In your configuration, define a simple cache manager (e.g., ConcurrentMapCacheManager) or integrate with a distributed cache like Redis.
  4. Test the Cache Behavior:
     Ensure that repeated calls within the cache expiry time do not trigger new API requests.