Maintain realtime counter [closed] - algorithm

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The following is an interview question which shows up here and here:
Given a timer time() with nanosecond accuracy and given the interface
interface RealTimeCounter:
void increment()
int getCountInLastSecond()
int getCountInLastMinute()
int getCountInLastHour()
int getCountInLastDay()
The getCountInLastX functions should return the number of times increment was called in the last X
Here's one suggested solution (paraphrased from the above blog entry):
Maintain an ArrayList of timestamps. When asked for a given counter, let's say, the count for the last second, perform a binary search for (timer.time() - ONE_SECOND_IN_NANOSECONDS), and return the list.length() - list_index. Then, as a background process at regular intervals we trim our data. Since we only need to maintain data for the last day, we can delete all entries prior to the last day.
Please critique this solution or offer a better performing one.