Implementing your own caching algorithm

In this section, let us start by implementing a simple cache algorithm and see its draw backs, and then show how spring caching can be used to solve the problems.

Let's draw a simple flow chart to look at the caching scenario:

Let's see how we can implement caching in a simple way. Think of generating a Fibonacci number. A Fibonacci number is generated by adding its previous two Fibonacci numbers. So we can compute a simple class in java and see how we can use caching here.

Let's create a map to cache the objects:

import java.util.HashMap;
import java.util.Map;
public class FibonacciCache {
  private Map<Long, Long> cachemap = new HashMap<>();
  public FibonacciCache() {
    // The base case for the Fibonacci Sequence
    cachemap.put(0L, 1L);
    cachemap.put(1L, 1L);
  }
  public Long getNumber(long index) {
    // Check if value is in cache
    if (cachemap.containsKey(index)) {
     return cachemap.get(index);
    }

  ...