Add EntityDyeEvent and CollarColorable interface

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

@@ -0,0 +1,26 @@
+package io.papermc.paper.entity;
+
+import org.bukkit.DyeColor;
+import org.bukkit.entity.LivingEntity;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Entities that can have their collars colored.
+ */
+@NullMarked
+public interface CollarColorable extends LivingEntity {
+
+    /**
+     * Get the collar color of this entity
+     *
+     * @return the color of the collar
+     */
+    DyeColor getCollarColor();
+
+    /**
+     * Set the collar color of this entity
+     *
+     * @param color the color to apply
+     */
+    void setCollarColor(DyeColor color);
+}

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

@@ -0,0 +1,82 @@
+package io.papermc.paper.event.entity;
+
+import org.bukkit.DyeColor;
+import org.bukkit.entity.Cat;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.Player;
+import org.bukkit.entity.Sheep;
+import org.bukkit.entity.Wolf;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.entity.EntityEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+/**
+ * Called when an entity is dyed. Currently, this is called for {@link Sheep}
+ * being dyed, and {@link Wolf}/{@link Cat} collars being dyed.
+ */
+@NullMarked
+public class EntityDyeEvent extends EntityEvent implements Cancellable {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final @Nullable Player player;
+    private DyeColor dyeColor;
+
+    private boolean cancelled;
+
+    @ApiStatus.Internal
+    public EntityDyeEvent(final Entity entity, final DyeColor dyeColor, final @Nullable Player player) {
+        super(entity);
+        this.dyeColor = dyeColor;
+        this.player = player;
+    }
+
+    /**
+     * Gets the DyeColor the entity is being dyed
+     *
+     * @return the DyeColor the entity is being dyed
+     */
+    public DyeColor getColor() {
+        return this.dyeColor;
+    }
+
+    /**
+     * Sets the DyeColor the entity is being dyed
+     *
+     * @param dyeColor the DyeColor the entity will be dyed
+     */
+    public void setColor(final DyeColor dyeColor) {
+        this.dyeColor = dyeColor;
+    }
+
+    /**
+     * Returns the player dyeing the entity, if available.
+     *
+     * @return player or {@code null}
+     */
+    public @Nullable Player getPlayer() {
+        return this.player;
+    }
+
+    @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;
+    }
+}