Simplify ExpiringSet implementation (#3969)

common/src/main/java/me/lucko/luckperms/common/command/CommandManager.java

@@ -79,6 +79,7 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutorService;
@@ -101,7 +102,7 @@ public class CommandManager {
             .build()
     );
     private final AtomicBoolean executingCommand = new AtomicBoolean(false);
-    private final ExpiringSet<UUID> playerRateLimit = new ExpiringSet<>(500, TimeUnit.MILLISECONDS);
+    private final Set<UUID> playerRateLimit = ExpiringSet.newExpiringSet(500, TimeUnit.MILLISECONDS);
     private final TabCompletions tabCompletions;
     private final Map<String, Command<?>> mainCommands;
 

common/src/main/java/me/lucko/luckperms/common/messaging/LuckPermsMessagingService.java

@@ -54,13 +54,14 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.Objects;
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 
 public class LuckPermsMessagingService extends AsyncInterface implements InternalMessagingService, IncomingMessageConsumer {
     private final LuckPermsPlugin plugin;
-    private final ExpiringSet<UUID> receivedMessages;
+    private final Set<UUID> receivedMessages;
     private final PushUpdateBuffer updateBuffer;
 
     private final MessengerProvider messengerProvider;
@@ -74,7 +75,7 @@ public class LuckPermsMessagingService extends AsyncInterface implements Interna
         this.messenger = messengerProvider.obtain(this);
         Objects.requireNonNull(this.messenger, "messenger");
 
-        this.receivedMessages = new ExpiringSet<>(5, TimeUnit.MINUTES);
+        this.receivedMessages = ExpiringSet.newExpiringSet(5, TimeUnit.MINUTES);
         this.updateBuffer = new PushUpdateBuffer(plugin);
     }
 

common/src/main/java/me/lucko/luckperms/common/model/manager/user/UserHousekeeper.java

@@ -30,6 +30,7 @@ import me.lucko.luckperms.common.model.User;
 import me.lucko.luckperms.common.plugin.LuckPermsPlugin;
 import me.lucko.luckperms.common.util.ExpiringSet;
 
+import java.util.Set;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 
@@ -41,16 +42,16 @@ public class UserHousekeeper implements Runnable {
     private final UserManager<?> userManager;
 
     // contains the uuids of users who have recently logged in / out
-    private final ExpiringSet<UUID> recentlyUsed;
+    private final Set<UUID> recentlyUsed;
 
     // contains the uuids of users who have recently been retrieved from the API
-    private final ExpiringSet<UUID> recentlyUsedApi;
+    private final Set<UUID> recentlyUsedApi;
 
     public UserHousekeeper(LuckPermsPlugin plugin, UserManager<?> userManager, TimeoutSettings timeoutSettings) {
         this.plugin = plugin;
         this.userManager = userManager;
-        this.recentlyUsed = new ExpiringSet<>(timeoutSettings.duration, timeoutSettings.unit);
+        this.recentlyUsed = ExpiringSet.newExpiringSet(timeoutSettings.duration, timeoutSettings.unit);
-        this.recentlyUsedApi = new ExpiringSet<>(5, TimeUnit.MINUTES);
+        this.recentlyUsedApi = ExpiringSet.newExpiringSet(5, TimeUnit.MINUTES);
     }
 
     // called when a player attempts a connection or logs out

common/src/main/java/me/lucko/luckperms/common/storage/implementation/file/watcher/FileWatcher.java

@@ -36,6 +36,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
@@ -97,7 +98,7 @@ public class FileWatcher extends AbstractFileWatcher {
         private final Path path;
 
         /** A set of files which have been modified recently */
-        private final ExpiringSet<String> recentlyModifiedFiles = new ExpiringSet<>(4, TimeUnit.SECONDS);
+        private final Set<String> recentlyModifiedFiles = ExpiringSet.newExpiringSet(4, TimeUnit.SECONDS);
 
         /** The listener callback functions */
         private final List<Consumer<Path>> callbacks = new CopyOnWriteArrayList<>();

common/src/main/java/me/lucko/luckperms/common/util/ExpiringSet.java

@@ -25,36 +25,21 @@
 
 package me.lucko.luckperms.common.util;
 
-import com.github.benmanes.caffeine.cache.Cache;
+import java.util.Collections;
-
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
-/**
+public final class ExpiringSet {
- * A simple expiring set implementation using Caffeine caches
+    private ExpiringSet() {}
- *
- * @param <E> element type
- */
-public class ExpiringSet<E> {
-    private final Cache<E, Long> cache;
-    private final long lifetime;
 
-    public ExpiringSet(long duration, TimeUnit unit) {
+    /**
-        this.cache = CaffeineFactory.newBuilder().expireAfterWrite(duration, unit).build();
+     * An expiring set using Caffeine caches
-        this.lifetime = unit.toMillis(duration);
+     *
+     * @param <E> the element type
+     * @return a new expiring set
+     */
+    public static <E> Set<E> newExpiringSet(long duration, TimeUnit unit) {
+        return Collections.newSetFromMap(CaffeineFactory.newBuilder().expireAfterWrite(duration, unit).<E, Boolean>build().asMap());
     }
 
-    public boolean add(E item) {
-        boolean present = contains(item);
-        this.cache.put(item, System.currentTimeMillis() + this.lifetime);
-        return !present;
-    }
-
-    public boolean contains(E item) {
-        Long timeout = this.cache.getIfPresent(item);
-        return timeout != null && timeout > System.currentTimeMillis();
-    }
-
-    public void remove(E item) {
-        this.cache.invalidate(item);
-    }
 }