public synchronized void addToSum(String user, Integer value)
{
- if (!state.containsKey(user))
- throw new IllegalStateException("No sumation for " + user + " in progress");
if (value == null || value < 1)
throw new IllegalArgumentException("Not a positive number: " + value);
- long result = state.get(user) + value;
- state.put(user, result);
+ long sum =
+ Optional
+ .ofNullable(state.get(user))
+ .orElse(0l);
+ state.put(user, sum + value);
}
public synchronized Long calculate(String user)