rename the package

src/main/java/xyz/mcutils/backend/common/ExpiringSet.java

@@ -0,0 +1,132 @@
+package cc.fascinated.common;
+
+import lombok.NonNull;
+import net.jodah.expiringmap.ExpirationPolicy;
+import net.jodah.expiringmap.ExpiringMap;
+
+import java.util.Iterator;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+/**
+ * A simple set that expires elements after a certain
+ * amount of time, utilizing the {@link ExpiringMap} library.
+ *
+ * @param <T> The type of element to store within this set
+ * @author Braydon
+ */
+public final class ExpiringSet<T> implements Iterable<T> {
+    /**
+     * The internal cache for this set.
+     */
+    @NonNull private final ExpiringMap<T, Long> cache;
+
+    /**
+     * The lifetime (in millis) of the elements in this set.
+     */
+    private final long lifetime;
+
+    public ExpiringSet(@NonNull ExpirationPolicy expirationPolicy, long duration, @NonNull TimeUnit timeUnit) {
+        this(expirationPolicy, duration, timeUnit, ignored -> {});
+    }
+
+    public ExpiringSet(@NonNull ExpirationPolicy expirationPolicy, long duration, @NonNull TimeUnit timeUnit, @NonNull Consumer<T> onExpire) {
+        //noinspection unchecked
+        this.cache = ExpiringMap.builder()
+                .expirationPolicy(expirationPolicy)
+                .expiration(duration, timeUnit)
+                .expirationListener((key, ignored) -> onExpire.accept((T) key))
+                .build();
+        this.lifetime = timeUnit.toMillis(duration); // Get the lifetime in millis
+    }
+
+    /**
+     * Add an element to this set.
+     *
+     * @param element the element
+     * @return whether the element was added
+     */
+    public boolean add(@NonNull T element) {
+        boolean contains = contains(element); // Does this set already contain the element?
+        this.cache.put(element, System.currentTimeMillis() + this.lifetime);
+        return !contains;
+    }
+
+    /**
+     * Get the entry time of an element in this set.
+     *
+     * @param element the element
+     * @return the entry time, -1 if not contained
+     */
+    public long getEntryTime(@NonNull T element) {
+        return contains(element) ? this.cache.get(element) - this.lifetime : -1L;
+    }
+
+    /**
+     * Check if an element is
+     * contained within this set.
+     *
+     * @param element the element
+     * @return whether the element is contained
+     */
+    public boolean contains(@NonNull T element) {
+        Long timeout = this.cache.get(element); // Get the timeout for the element
+        return timeout != null && (timeout > System.currentTimeMillis());
+    }
+
+    /**
+     * Check if this set is empty.
+     *
+     * @return whether this set is empty
+     */
+    public boolean isEmpty() {
+        return this.cache.isEmpty();
+    }
+
+    /**
+     * Get the size of this set.
+     *
+     * @return the size
+     */
+    public int size() {
+        return this.cache.size();
+    }
+
+    /**
+     * Remove an element from this set.
+     *
+     * @param element the element
+     * @return whether the element was removed
+     */
+    public boolean remove(@NonNull T element) {
+        return this.cache.remove(element) != null;
+    }
+
+    /**
+     * Clear this set.
+     */
+    public void clear() {
+        this.cache.clear();
+    }
+
+    /**
+     * Get the elements in this set.
+     *
+     * @return the elements
+     */
+    @NonNull
+    public Set<T> getElements() {
+        return this.cache.keySet();
+    }
+
+    /**
+     * Returns an iterator over elements of type {@code T}.
+     *
+     * @return an Iterator.
+     */
+    @Override @NonNull
+    public Iterator<T> iterator() {
+        return this.cache.keySet().iterator();
+    }
+}