In memory state, drop data after X time

[Raphael Hsieh <ra...@gmail.com>]

At the end of the documentation here
https://github.com/nathanmarz/storm/wiki/Trident-tutorial#state it mentions:

 State's are not required to hold onto state forever. For example, you
could have an in-memory State implementation that only keeps the last X
hours of data available and drops anything older. Take a look at the
implementation of the Memcached
integration<https://github.com/nathanmarz/trident-memcached/blob/master/src/jvm/trident/memcached/MemcachedState.java>
for
an example State implementation.

How would I go about doing  this ?
In Trident I haven't found an easy way to store a state for a period of
time, then flush it out to an external datastore.

-- 
Raphael Hsieh