sorted set FIFO

sorted-set-fifo.java

...
Jedis j;
j.connect();


/*
*using NX parameter on ZADD command -> ADD IF NOT EXISTS -> UNIQUE

*using Timestamp as score -> always increasing -> always MAX score -> Like RPUSH on a list

*minimum score = oldest element -> ZPOPMIN will always give the oldest element. Like LPOP on a List
*/
j.zadd("foo", Instant.now().toEpochMilli(),"aa", ZAddParams.zAddParams().nx());
j.zadd("foo", Instant.now().toEpochMilli(),"bb", ZAddParams.zAddParams().nx());
j.zadd("foo", Instant.now().toEpochMilli(),"cc", ZAddParams.zAddParams().nx());
j.zadd("foo", Instant.now().toEpochMilli(),"dd", ZAddParams.zAddParams().nx());

for(int i=0;i<4;i++)
    j.zpopmin("foo");