Tair (Redis® OSS-Compatible):Implement distributed leaderboards by using exZset

Code example

This solution requires the TairJedis client, which is developed by Tair.

1. Add the pom.xml configuration.

           <dependency>
               <groupId>com.aliyun.tair</groupId>
               <artifactId>alibabacloud-tairjedis-sdk</artifactId>
               <version>5.3.1</version>
           </dependency>

2. Sample code.

   import io.valkey.JedisPool;
   import io.valkey.JedisPoolConfig;
   import com.aliyun.tair.tairzset.*;
   
   public class DistributedLeaderBoardExample {
       // Configure the instance endpoint, port, password, and other information.
       private static final int DEFAULT_CONNECTION_TIMEOUT = 5000;
       private static final int DEFAULT_SO_TIMEOUT = 2000;
       private static final String HOST = "<r-bp1mx0ydsivrbp****.redis.rds.aliyuncs.com>";
       private static final int PORT = 6379;
       private static final String PASSWORD = "<Pass****word>";
       private static final JedisPoolConfig config = new JedisPoolConfig();
   
       // Configure the distributed leaderboard.
       private static final int shardKeySize = 10;  // The number of underlying sub-leaderboards.
       private static final int pageSize = 10;      // The number of members on each page of the leaderboard.
       private static final boolean reverse = true; // In this example, members are sorted in descending order.
       private static final boolean useZeroIndexForRank = false; // In this example, ranks start from 1.
   
       public static void main(String[] args) {
           JedisPool jedisPool = new JedisPool(config, HOST, PORT, DEFAULT_CONNECTION_TIMEOUT,
                   DEFAULT_SO_TIMEOUT, PASSWORD, 0, null);
                   
           // Create a distributed leaderboard. In this example, the key is named distributed_leaderboard.
           DistributedLeaderBoard dlb = new DistributedLeaderBoard("distributed_leaderboard", jedisPool,
               shardKeySize, pageSize, reverse, useZeroIndexForRank);
   
           // If the number of gold medals is the same, sort by the number of silver medals. If the number of silver medals is also the same, sort by the number of bronze medals.
           //                    Gold Silver Bronze
           dlb.addMember("A",     32,  21, 16);
           dlb.addMember("D",     14,  4,  16);
           dlb.addMember("C",     20,  7,  12);
           dlb.addMember("B",     25,  29, 21);
           dlb.addMember("E",     13,  21, 18);
           dlb.addMember("F",     13,  17,  14);
   
           // Get the rank of A.
           dlb.rankFor("A"); // 1
           System.out.println(dlb.rankFor("A"));
   
           // Get the top 3.
           dlb.top(3);
           System.out.println(dlb.top(3));
           // [{"member":"A","score":"32#21#16","rank":1},
           // {"member":"B","score":"25#29#21","rank":2},
           // {"member":"C","score":"20#7#12","rank":3}]
       }
   }

   Parameters:

   Parameter	Type	Description
   shardKeySize	int	The number of underlying sub-leaderboards. The default value is 10. This number cannot be dynamically scaled out. Plan for this number in the initial phase of your service.
   pageSize	int	The number of members on each page of the leaderboard. The default value is 10.
   reverse	boolean	Valid values: false (default): Sorts in ascending order. true: Sorts in descending order.
   useZeroIndexForRank	boolean	Valid values: true (default): Ranks start from 0. false: Ranks start from 1.

   For more operations, see the com.aliyun.tair.tairzset.DistributedLeaderBoard class in alibabacloud-tairjedis-sdk.

Appendix: Comparison between conventional and distributed leaderboards

The following table compares the implementation of basic features for conventional and distributed leaderboards.