Caching Techniques

Caching is a technique used in system design to improve the performance and efficiency of an application by storing frequently accessed data in a cache. The cache acts as a temporary storage that stores computed or retrieved data for subsequent access.

Caching can be applied at various levels within a system, including database caching, object caching, query result caching, and web page caching. Each level of caching serves a specific purpose and provides benefits such as:

• Improved response time: Caching reduces the need to perform expensive operations, such as database queries or calculations, by serving the cached data directly.
• Reduced load on resources: By serving cached data, system resources like databases or external APIs are utilized less frequently, reducing the overall load on these resources.
• Scalability: Caching can help improve the scalability of an application by reducing the load on the underlying resources and enabling the system to handle more user requests.
• Consistency: Caching can provide a consistent view of data by storing frequently accessed data in a cache and reducing the dependency on slower data sources.

To implement caching, a popular data structure used is a cache map or hash map. This data structure allows for efficient key-value pair storage and retrieval. Here's an example of a simple cache implementation in Java:

1// Cache class that implements a basic cache with a fixed capacity
2
3class Cache {
4  private int capacity;
5  private Map<String, String> cacheMap;
6
7  public Cache(int capacity) {
8    this.capacity = capacity;
9    this.cacheMap = new LinkedHashMap<>(capacity, 0.75f, true) {
10      @Override
11      protected boolean removeEldestEntry(Map.Entry<String, String> eldest) {
12        return size() > capacity;
13      }
14    };
15  }
16
17  public void put(String key, String value) {
18    cacheMap.put(key, value);
19  }
20
21  public String get(String key) {
22    return cacheMap.get(key);
23  }
24}

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}

class Main {

  public static void main(String[] args) {

    // Replace with your caching logic here

    Cache cache = new Cache(100); // Create a cache with a capacity of 100

    cache.put("key1", "value1"); // Add key-value pair to cache

    cache.put("key2", "value2");

    String value1 = cache.get("key1"); // Retrieve value from cache

    System.out.println(value1); // Output: value1

    String value2 = cache.get("key2");

    System.out.println(value2); // Output: value2

  }

}

​

class Cache {

  private int capacity;

  private Map<String, String> cacheMap;

​

  public Cache(int capacity) {

    this.capacity = capacity;

    this.cacheMap = new LinkedHashMap<>(capacity, 0.75f, true) {

      @Override

      protected boolean removeEldestEntry(Map.Entry<String, String> eldest) {

        return size() > capacity;

      }

    };

  }

​

  public void put(String key, String value) {

    cacheMap.put(key, value);