public abstract class Cache<K, V> {

	private Map<K, V> map = new HashMap<>();

	public void add(K key, V val) {
		map.put(key, val);
	}

	public void remove(K key) {
		map.remove(key);
	}

	public boolean has(K key) {
		return map.containsKey(key);
	}

	public V get(K key) {
		return map.get(key);
	}

}