Add EntityEffectTickEvent (#11838)

paper-api/src/main/java/io/papermc/paper/event/entity/EntityEffectTickEvent.java

@@ -0,0 +1,75 @@
+package io.papermc.paper.event.entity;
+
+import org.bukkit.entity.LivingEntity;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityEvent;
+import org.bukkit.potion.PotionEffectType;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * An event that is triggered when an entity receives a potion effect instantly
+ * or when the potion effect is applied on each tick (e.g. every 25 ticks for Poison level 1).
+ * <p>
+ * For example, this event may be called when an entity regenerates health
+ * or takes poison damage as a result of a potion effect.
+ */
+@NullMarked
+public class EntityEffectTickEvent extends EntityEvent implements Cancellable {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final PotionEffectType type;
+    private final int amplifier;
+    private boolean cancelled;
+
+    @ApiStatus.Internal
+    public EntityEffectTickEvent(final LivingEntity entity, final PotionEffectType type, final int amplifier) {
+        super(entity);
+        this.type = type;
+        this.amplifier = amplifier;
+    }
+
+    @Override
+    public LivingEntity getEntity() {
+        return (LivingEntity) super.getEntity();
+    }
+
+    /**
+     * Gets the type of the potion effect associated with this event.
+     *
+     * @return the {@link PotionEffectType} of the effect
+     */
+    public PotionEffectType getType() {
+        return type;
+    }
+
+    /**
+     * Gets the amplifier level of the potion effect associated with this event.
+     *
+     * @return the amplifier level of the potion effect
+     */
+    public int getAmplifier() {
+        return amplifier;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    @Override
+    public void setCancelled(final boolean cancel) {
+        this.cancelled = cancel;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}