TTLHashMap

TTLHashMap is a Java library that provides a thread-safe hash map implementation with support for time-to-live (TTL) entries. This data structure is useful for caching scenarios where you want entries to automatically expire after a specified duration.

Features

• Thread-safe operations using ConcurrentHashMap
• Configurable time-to-live (TTL) for entries
• Automatic removal of expired entries
• Support for custom actions when entries expire
• Flexible TTL units (seconds, minutes, hours, etc.)

Requirements

Use Java 8+

Usage

Here's a quick example of how to use TTLHashMap:

import com.athingforcode.TTLHashMap;
import java.util.concurrent.TimeUnit;

public class Example {
    public static void main(String[] args) {
        TTLHashMap<String, String> map = new TTLHashMap<>();

        // Add an entry that expires after 5 seconds
        map.put("key1", "value1", 5, TimeUnit.SECONDS, (k, v) -> System.out.println("Expired: " + k + " = " + v));

        // Add a non-expiring entry
        map.put("key2", "value2", -1, TimeUnit.SECONDS, null);

        // Retrieve a value
        String value = map.get("key1");

        // Remove an entry
        map.remove("key2");

        // Don't forget to shut down the map when you're done
        map.shutdown();
    }
}

API Reference

TTLHashMap<K, V>

• TTLHashMap(): Constructs a new TTLHashMap.
• void put(K key, V value, long ttl, TimeUnit unit, BiConsumer<K, V> actionWhenExpired): Puts a key-value pair into the map with an optional expiration time and expiration action.
• V get(K key): Retrieves the value associated with the specified key.
• void remove(K key): Removes the mapping for the specified key from this map if present.
• void shutdown(): Shuts down the TTLHashMap and its scheduler.

License

Apache License 2.0