Leashable API

paper-api/src/main/java/io/papermc/paper/entity/Leashable.java

@@ -0,0 +1,37 @@
+package io.papermc.paper.entity;
+
+import org.bukkit.entity.Entity;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+/**
+ * Represents an entity that can be leashed.
+ */
+@NullMarked
+public interface Leashable extends Entity {
+
+    /**
+     * Returns whether the entity is currently leashed.
+     *
+     * @return whether the entity is leashed
+     */
+    boolean isLeashed();
+
+    /**
+     * Gets the entity that is currently leading this entity.
+     *
+     * @return the entity holding the leash
+     * @throws IllegalStateException if not currently leashed
+     */
+    Entity getLeashHolder() throws IllegalStateException;
+
+    /**
+     * Sets the leash on this entity to be held by the supplied entity.
+     * <p>
+     * This method has no effect on players.
+     *
+     * @param holder the entity to leash this entity to, or {@code null} to unleash
+     * @return whether the operation was successful
+     */
+    boolean setLeashHolder(@Nullable Entity holder);
+}