LRU Cache with TTL and Priority

This project implements a Python LRU (Least Recently Used) cache, enhanced with TTL (time to live) expiration and a priority-based eviction strategy.

Features

• TTL:: old items get expired
• Priority-based eviction: removes low-priority items first
• Thread-safe: uses Locks to handle concurrency

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Available Methods

get(key: int) -> Any

• Returns the value of the item with the given key, if present and Moves the accessed item to the front.
• Returns None if the key is not present.

put(key: int, value: Any, ttl: float, priority: int) -> None

• Inserts a new item or updates an existing one.
• The item expires after time to live (ttl) number of seconds.
• If the cache is full:
  • Expired items are evicted first.
  • If no expired items, items with the lowest priority are removed.
  • If multiple items share the lowest priority, the least recently used one is removed.

clear() -> None

• Clears all items from the cache.

__str__() -> str

• Returns a string representing the cache contents.

__contains__() -> bool

• Returns True if the key is stored in the cache.

__len__() -> bool

• Returns the number of items stored in the cache.

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Quick Start

from src.cache import Cache

cache = Cache(capacity=3)

cache.put(1, "apple", time.time()+120, priority=2)
cache.put(2, "banana", time.time()+120, priority=3)

print(cache.get(1))
print(cache)
print(len(cache))