package me.corriekay.simplymodular.util;

import java.util.HashMap;
import java.util.Map;

import com.google.common.collect.MapMaker;
import com.google.inject.Provider;

/**
 * HashCache is a cache designed to store both strong and weak references to objects. This is designed to help with data concurrency.
 * @author Corrie
 */
public class HashCache<K, V> {
	private final Map<K, V> map = new HashMap<>();
	private final Map<K, V> cache = new MapMaker().weakValues().makeMap();
	
	public V get(K k) {
		if(cache.containsKey(k)) return cache.get(k);
		return map.get(k);
	}
	
	public V optGet(K k, Provider<V> p) {
		V v = get(k);
		if(v == null) {
			v = p.get();
			cache.put(k, v);
		}
		return v;
	}
	
	public void put(K k, Provider<V> p) {
		if(!cache.containsKey(k)) {
			V v = p.get();
			cache.put(k, v);
			map.put(k, v);
		} else {
			map.put(k, cache.get(k));
		}
	}
	
	public void remove(K k) {
		map.remove(k);
	}
	
	public void hardRemove(K k) {
		remove(k);
		cache.remove(k);
	}
}