interview sample

dp.java

@Data
class Result {
  // ...
}

@Data
class Input {
  // ...
}

interface DataProvider {
    Result calculate(Input input);
}

@RequiredArgsConstructor
public class DataProviderCached implements DataProvider {
    private final DataProvider delegate;
    private final Map<Input, Result> cache = new ConcurrentHashMap<>();

    @Override
    public Result calculate(Input input) {
        return cache.computeIfAbsent(input, delegate::calculate);
    }
}