Simple Redis ZSET Demo with Dates

RedisSortedSetQueryByTimeDemo.java

package redis;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

import java.util.Calendar;
import java.util.Date;
import java.util.Set;

/**
 * Created with IntelliJ IDEA.
 * User: ssimanta
 * Date: 6/13/13
 * Time: 6:36 PM
 *
 * Simple demo that gets a list from redis on a perodic basis

 */
public class RedisSortedSetQueryByTimeDemo {


    public static final String REDIS_HISTORY_TABLE_KEY = "history.demo";
    protected JedisPool redisPool;



    public static void main(String args[])   throws Exception
    {
        RedisSortedSetQueryByTimeDemo demo = new RedisSortedSetQueryByTimeDemo("localhost");

        //populate some dummy date for testing
        //In when running the real program we don't have to do this step. The backend analysis will be populating the Redis database
        //all you need to know is the Redis key where the data is being stored

        int hoursAgo = 2;
        demo.populateDummyDataInRedis(hoursAgo*(60*60), demo.getDateInPast(hoursAgo).getTime(), 1);

        Set<String> resutls = demo.getData(demo.getDateInPast(1).getTime(), demo.getDateInPast(0).getTime());
        System.out.println(resutls);

    }

    public RedisSortedSetQueryByTimeDemo(final String redisHost)
    {

        //create the Redis connection pool
        redisPool = new JedisPool(new JedisPoolConfig(), redisHost);


        Date dateinPast = getDateInPast(1);
        long timeInPast = dateinPast.getTime();

        //create a date string
        System.out.println("Date: " + dateinPast + " time: " + timeInPast  );
        System.out.println("Date from mili since epoch:" + new Date(timeInPast));



    }


    public Set<String> getData(final long startTimeStamp, final long endTimeStamp)
    {
         Jedis redis = redisPool.getResource();
         java.util.Set<String> results = redis.zrangeByScore(REDIS_HISTORY_TABLE_KEY, startTimeStamp, endTimeStamp);
         return results;
    }

    /**
     * Return a java.util.Date object that represents the actual date <code>hoursAgo</code> ago in the past.
     * For example, if the current time is 12:08 PM then this method will return 11:00 AM
     *
     * @param hoursAgo
     * @return
     */
    public Date getDateInPast(int hoursAgo)
    {


            Date date = new Date();
            Calendar cal = Calendar.getInstance();
            cal.setTime(date);
            cal.set(Calendar.HOUR_OF_DAY, cal.get(Calendar.HOUR_OF_DAY) - hoursAgo);
            cal.set(Calendar.MINUTE, 0);
            cal.set(Calendar.SECOND, 0);
            cal.set(Calendar.MILLISECOND, 0);
            date = cal.getTime();

            return date;


    }

    public void populateDummyDataInRedis(final int numberOfDummyEntries, final long startTimeStampInPast, final int gapInSeconds)       throws Exception
    {

        double score = 0.0;

        Jedis jedis = redisPool.getResource();
        for( int i =0; i<numberOfDummyEntries; i++)
        {

            int p = new Double(Math.random()*1000).intValue();
            int n =  new Double(Math.random()*1000).intValue();
            String sentimentString = "{ \"P\":" + p + ", \"N\":" + n + "}";
            //score = System.currentTimeMillis();
            score = startTimeStampInPast + gapInSeconds*1000;
            System.out.println("time: " + score + " " + sentimentString);
            jedis.zadd(REDIS_HISTORY_TABLE_KEY, score, sentimentString);//ZADD
            //Thread.sleep(gapInMS);


        }

        redisPool.returnResource(jedis);
    }
}