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Crache

Crache is a simple, generic caching library written in Java. It supports an LRU (Least Recently Used) eviction policy out of the box and can be extended to support other eviction policies. The cache provides basic get, put, and evict operations.

Features

  • Generic Key-Value Storage: Use any type for keys and values.
  • LRU Eviction Policy: Automatically evicts the least recently used item when the cache reaches capacity.
  • Extensibility: Can be configured to support other eviction policies.

Class Overview

Crache

The Crache<K, V> class is a generic implementation of a cache with the following main components:

  • HashMap for Storage: Internally uses a HashMap<K, V> to store key-value pairs.
  • LRU List for Eviction: Maintains an eviction list to track and evict least recently used items.
  • Eviction Policy: Currently supports LRU as the default policy.

Constructors

  • Crache(): Initializes the cache with LRU as the default eviction policy.
  • Crache(EvictionPolicy policy): Initializes the cache with a specified eviction policy.

Public Methods

V get(K key)

Fetches a value associated with the given key.

  • Returns: The value if it exists in the cache; otherwise, null.
  • Side Effect: Promotes the accessed key to the most recent position in the eviction list if it exists.

void put(K key, V value)

Inserts or updates the value associated with the key.

  • Effect: Adds the key to the eviction list and stores the value in the HashMap.

void evict()

Removes the least recently used item from the cache.

  • Effect: Evicts the first item in the eviction list and removes its corresponding key-value pair from the store.

HashMap<K, V> getStore()

Returns the internal storage used by the cache.

LRU<K> getEvictionList()

Returns the eviction list (used internally for LRU eviction).

String toString()

Provides a string representation of the cache's contents.

Usage Example

import dev.nmanu.Crache;

public class Main {
    public static void main(String[] args) {
        Crache<String, Integer> cache = new Crache<>();

        // Insert key-value pairs
        cache.put("A", 1);
        cache.put("B", 2);
        cache.put("C", 3);

        // Access elements
        System.out.println("Get A: " + cache.get("A")); // HIT
        System.out.println("Cache state:\n" + cache);

        // Evict least recently used
        cache.evict();
        System.out.println("After eviction:\n" + cache);
    }
}

Output

HIT: A : LRU.Node@12345
Get A: 1
Cache state:
A : 1
B : 2
C : 3

After eviction:
B : 2
C : 3

Installation

To use this library, clone the repository and include the dev.nmanu package in your project.

git clone https://github.com/your-username/crache.git

Future Work

  • Support for additional eviction policies (e.g., LFU, FIFO).
  • Configurable maximum cache size.
  • Thread-safe implementation for concurrent environments.

Contributing

Feel free to fork the repository, submit issues, or create pull requests for improvements and bug fixes.

License

This project is licensed under the MIT License. See the LICENSE file for details.