FineGrainedSafeMemoizer.java

/**
 * Iteration 3: Fine-Grained Safe Memoizer
 * A thread-safe implementation of a memoizer that caches computed results using fine-grained locking.
 * This implementation uses ConcurrentHashMap to allow concurrent access to the cache,
 * enabling multiple threads to compute and cache results simultaneously without blocking each other.
 */
public class FineGrainedSafeMemoizer<A,V> implements Computable<A,V> {
    private final ConcurrentHashMap<A,V> cache = new ConcurrentHashMap<>();
    private final Computable<A,V> computable;

    public FineGrainedSafeMemoizer(Computable<A,V> computable) {
        this.computable = computable;
    }

    @Override
    public V compute(A arg) throws InterruptedException {
        V result = cache.get(arg);
        if (result == null) {
            result = computable.compute(arg);
            cache.put(arg, result);
        }
        return result;
    }
}