Analysis of the core principle of Caffeine Cache framework

Analysis of the core principle of Caffeine Cache framework In many Java applications, cache is one of the important components to improve performance and reduce system loads.Caffeine Cache is a high -performance Java cache framework that is widely used in various Java applications.This article will analyze the core principles of the Caffeine Cache framework and provide some Java code examples to help readers better understand. The core principles of the Caffeine Cache framework can be divided into the following aspects: data structure, cache strategy, and expired strategy. 1. Data structure: The core data structure of the Caffeine Cache framework is a cache memory based on the Hash Table. It uses an algorithm called LRU (LEAST Recently Use) to manage data in the cache.The LRU algorithm guarantees that the recently used data will be replaced by the cache, so as to maintain the reasonable use of the cache capacity. The spread list of Caffeine Cache uses the combined structure of the linked list and the red and black tree.The linked list is used to record the order of the cache item that has been visited recently, and the red and black trees are used to quickly find the order of the inductance and maintain the inductance.The design of this combined data structure enables Caffeine Cache to have good performance in fast search and deleting cache items in the order of access. 2. Cache strategy: Caffeine Cache framework supports a variety of cache strategies, which can choose suitable strategies according to the needs of the application.There are several common cache strategies: -Setal loading: When there is no value corresponding to a key in the cache, the Caffeine Cache will automatically call the user -specified loading function to load the value and save it into the cache.This strategy applies to the scene that needs to ensure data consistency and avoid cache penetration problems. -In asynchronous loading: Similar to synchronous loading, but the loading function will be executed in an asynchronous thread, so as not to block the main thread.This strategy is suitable for scenes that are not high in loading time, which can significantly improve concurrency. -The manual loading: Users need to manually call the load method to load the cache item.This strategy applies to the scene that requires more detailed control of cache loading. 3. Expired strategy: The Caffeine Cache framework comes from the expiration time of the cache through the expiration time of the cache item.There are several common expiration strategies: -The expiration strategy based on time: When the cache item is added to the cache, a expiration time can be set.Once the cache item expires, it will be automatically cleaned.This strategy is suitable for unchanged data and can save cache space. -Ductive strategy based on size: When the number of cache items reaches a certain threshold, the framework will automatically clean up the most recent cache items.This strategy applies to a scene with limited cache space. -The manual expiration: Users can manually call the INVALIDATE method to clear the specified cache item.This strategy applies to the scene that needs to update the cache data dynamically. The following is a simple example, demonstrating how to use the Caffeine Cache framework: import com.github.benmanes.caffeine.cache.Cache; import com.github.benmanes.caffeine.cache.Caffeine; public class CaffeineCacheExample { public static void main(String[] args) { Cache<String, Integer> cache = Caffeine.newBuilder() .maximumSize(100) .build(); cache.put("key1", 100); Integer value = cache.getIfPresent("key1"); System.out.println (value); // Output: 100 cache.invalidate("key1"); value = cache.getIfPresent("key1"); System.out.println (value); // Output: null } } In the above example, we created a cache with a maximum capacity of 100.By calling the PUT method, we put a key value into the cache.Then, we use the GetifreSENT method to obtain the corresponding value of the specified key in the cache.Finally, we called the INVALIDATE method manually to remove the specified cache item. In summary, the core principles of the Caffeine Cache framework include data structure, cache strategies and expiry strategies.It manages the cache items through efficient scattered list data structures, providing a variety of cache strategies and expired strategies to meet the needs of different scenarios.Through reasonable configuration, Caffeine Cache can significantly improve the performance and concurrency of Java applications.