Cache love calculator results in RAM

src/main/java/wtf/beatrice/hidekobot/Cache.java

@@ -14,7 +14,10 @@ import wtf.beatrice.hidekobot.util.Logger;
 import java.awt.*;
 import java.lang.reflect.Field;
 import java.time.LocalDateTime;
+import java.util.HashMap;
 import java.util.Random;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
 
 public class Cache
 {
@@ -28,6 +31,12 @@ public class Cache
     // the seed is updated periodically.
     private static final Random randomInstance = new Random();
 
+    // map to store results of "love calculator", to avoid people re-running the same command until
+    // they get what they wanted.
+    // i didn't think this was worthy of a whole database table with a runnable checking for expiration,
+    // and it will get cleared after a few minutes anyway, so RAM caching is more than good enough.
+    private static final HashMap<String, Integer> loveCalculatorValues = new HashMap<>();
+
     private static PropertiesSource propertiesSource = null;
     private static ConfigurationSource configurationSource = null;
     private static DatabaseSource databaseSource = null;
@@ -42,6 +51,9 @@ public class Cache
     // used to count e.g. uptime
     private static LocalDateTime startupTime = null;
 
+    // the scheduler that should always be used when running a scheduled task.
+    private final static ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor(); // todo: try-with-resources
+
     private final static String execPath = System.getProperty("user.dir");
     private static final String botName = "Hideko";
 
@@ -287,4 +299,31 @@ public class Cache
      */
     public static String getBotPrefix() { return botPrefix; }
 
+    public static void cacheLoveCalculatorValue(String userId1, String userId2, int value)
+    {
+        String merged = userId1 + "|" + userId2;
+        loveCalculatorValues.put(merged, value);
+    }
+
+    @Nullable
+    public static Integer getLoveCalculatorValue(String userId1, String userId2)
+    {
+        String merged1 = userId1 + "|" + userId2;
+        String merged2 = userId2 + "|" + userId1;
+        Integer value = null;
+        value = loveCalculatorValues.get(merged1);
+        if(value == null) value = loveCalculatorValues.get(merged2);
+        return value;
+    }
+
+    public static void removeLoveCalculatorValue(String userId1, String userId2)
+    {
+        loveCalculatorValues.remove(userId1 + "|" + userId2);
+        loveCalculatorValues.remove(userId2 + "|" + userId1);
+    }
+
+    public static ScheduledExecutorService getScheduler() {
+        return scheduler;
+    }
+
 }

src/main/java/wtf/beatrice/hidekobot/HidekoBot.java

@@ -178,7 +178,7 @@ public class HidekoBot
         }
 
         // start scheduled runnables
-        ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor(); // todo: try-with-resources
+        ScheduledExecutorService scheduler = Cache.getScheduler();
         ExpiredMessageTask expiredMessageTask = new ExpiredMessageTask();
         scheduler.scheduleAtFixedRate(expiredMessageTask, 5, 5, TimeUnit.SECONDS); //every 5 seconds
         HeartBeatTask heartBeatTask = new HeartBeatTask();

src/main/java/wtf/beatrice/hidekobot/commands/base/LoveCalculator.java

@@ -6,11 +6,23 @@ import net.dv8tion.jda.api.entities.User;
 import wtf.beatrice.hidekobot.Cache;
 import wtf.beatrice.hidekobot.util.RandomUtil;
 
+import java.util.concurrent.TimeUnit;
+
 public class LoveCalculator
 {
-    public static MessageEmbed buildEmbed(User author, User user1, User user2)
+    public static MessageEmbed buildEmbedAndCacheResult(User author, User user1, User user2)
     {
-        int loveAmount = RandomUtil.getRandomNumber(0, 100);
+        String userId1 = user1.getId();
+        String userId2 = user2.getId();
+
+        Integer loveAmount = Cache.getLoveCalculatorValue(userId1, userId2);
+        if(loveAmount == null)
+        {
+            loveAmount = RandomUtil.getRandomNumber(0, 100);
+            Cache.cacheLoveCalculatorValue(userId1, userId2, loveAmount);
+            Cache.getScheduler().schedule(() ->
+                    Cache.removeLoveCalculatorValue(userId1, userId2), 10, TimeUnit.MINUTES);
+        }
 
         String formattedAmount = loveAmount + "%";
         if(loveAmount <= 30) formattedAmount += "... \uD83D\uDE22";

src/main/java/wtf/beatrice/hidekobot/commands/message/LoveCalculatorCommand.java

@@ -1,6 +1,5 @@
 package wtf.beatrice.hidekobot.commands.message;
 
-import net.dv8tion.jda.api.EmbedBuilder;
 import net.dv8tion.jda.api.Permission;
 import net.dv8tion.jda.api.entities.IMentionable;
 import net.dv8tion.jda.api.entities.Mentions;
@@ -9,12 +8,10 @@ import net.dv8tion.jda.api.entities.User;
 import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import wtf.beatrice.hidekobot.Cache;
 import wtf.beatrice.hidekobot.HidekoBot;
 import wtf.beatrice.hidekobot.commands.base.LoveCalculator;
 import wtf.beatrice.hidekobot.objects.commands.CommandCategory;
 import wtf.beatrice.hidekobot.objects.commands.MessageCommand;
-import wtf.beatrice.hidekobot.util.RandomUtil;
 
 import java.util.Arrays;
 import java.util.LinkedList;
@@ -88,7 +85,7 @@ public class LoveCalculatorCommand implements MessageCommand
             user2 = HidekoBot.getAPI().retrieveUserById(mentionedUserId).complete();
         }
 
-        MessageEmbed embed = LoveCalculator.buildEmbed(event.getAuthor(), user1, user2);
+        MessageEmbed embed = LoveCalculator.buildEmbedAndCacheResult(event.getAuthor(), user1, user2);
         event.getChannel().sendMessageEmbeds(embed).queue();
 
     }

src/main/java/wtf/beatrice/hidekobot/commands/slash/LoveCalculatorCommand.java

@@ -55,7 +55,7 @@ public class LoveCalculatorCommand extends SlashCommandImpl
             secondUser = event.getUser();
         }
 
-        MessageEmbed embed = LoveCalculator.buildEmbed(event.getUser(), firstUser, secondUser);
+        MessageEmbed embed = LoveCalculator.buildEmbedAndCacheResult(event.getUser(), firstUser, secondUser);
         event.replyEmbeds(embed).queue();
     }
 }