NAME

       Tie::Hash::Expire - Hashes with keys that expire after a user-set period.

SYNOPSIS

         use Tie::Hash::Expire;

         my %test;
         tie %test, 'Tie::Hash::Expire', {'expire_seconds' => 10};

         $test{'dog'} = 'doghouse';
         sleep 5;
         $test{'bird'} = 'nest';
         sleep 6;

         print keys %test, "\n";       # The only key is 'bird'

         my %hi_res;
         tie %hi_res, 'Tie::Hash::Expire', {'expire_seconds' => 5.21};
               # Decimal number of seconds works if you have Time::HiRes

ABSTRACT

       Hashes tied to Tie::Hash::Expire have keys that cease to exist 'expire_seconds' after
       their most recent modification or their creation.

DESCRIPTION

       Hashes tied to Tie::Hash::Expire behave like normal hashes in all respects except that
       when a key is added or the value associated with a key is changed, the current time is
       stored, and after 'expire_seconds' the key and value are removed from the hash.

       Resolutions finer than seconds are available if the module finds access to Time::HiRes.
       If Time::HiRes is available, you can expect expiration to be accurate to 0.001 seconds.
       You may specify 'expire_seconds' to be decimal numbers like 5.12 .  If Time::HiRes is
       available, this number will be used precisely.  If you specify a decimal number and don't
       have access to Time::HiRes, a warning is generated and the code will function as though
       you specified the next higher integer.

       The number of seconds specified by 'expire_seconds' is taken to mean an absolute maximum
       lifespan for the key, at the resolution described above.  In other words, if you set
       'expire_seconds' to 1 second, and do not have Time::HiRes, keys could expire as quickly as
       the next machine instruction, but will not last longer than 1 second.

AUTHOR

       Jeff Yoak, <jeff@yoak.com>

COPYRIGHT AND LICENSE

       Copyright 2004 by Jeff Yoak

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.