Add LivingEntity knockback API (#8479)

patches/api/0403-Add-entity-knockback-API.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: MelnCat <melncatuwu@gmail.com>
+Date: Sun, 16 Oct 2022 12:10:00 -0700
+Subject: [PATCH] Add entity knockback API
+
+
+diff --git a/src/main/java/org/bukkit/entity/LivingEntity.java b/src/main/java/org/bukkit/entity/LivingEntity.java
+index 319e4571aca24d1e3f6c85b7435d65c0e77a5245..c9a44e8024f903da83181ee752c971bab22c8895 100644
+--- a/src/main/java/org/bukkit/entity/LivingEntity.java
++++ b/src/main/java/org/bukkit/entity/LivingEntity.java
+@@ -1003,5 +1003,17 @@ public interface LivingEntity extends Attributable, Damageable, ProjectileSource
+             this.swingOffHand();
+         }
+     }
++
++    /**
++     * Knocks back this entity from a specific direction with a specified strength. Mechanics such
++     * as knockback resistance will be factored in.
++     *
++     * The direction specified in this method will be the direction of the source of the knockback,
++     * so the entity will be pushed in the opposite direction.
++     * @param strength The strength of the knockback. Must be greater than 0.
++     * @param directionX The relative x position of the knockback source direction
++     * @param directionZ The relative z position of the knockback source direction
++     */
++    void knockback(double strength, double directionX, double directionZ);
+     // Paper end
+ }

patches/server/0928-Add-entity-knockback-API.patch

@@ -0,0 +1,22 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: MelnCat <melncatuwu@gmail.com>
+Date: Sun, 16 Oct 2022 12:10:17 -0700
+Subject: [PATCH] Add entity knockback API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+index e807ef287136e7b3931197e45434a3f618cf3054..06559a620b36f744c3d9fa2754e3c3eabead4752 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+@@ -977,5 +977,11 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
+         }
+         throw new IllegalArgumentException(entityCategory + " is an unrecognized entity category");
+     }
++
++    @Override
++    public void knockback(double strength, double directionX, double directionZ) {
++        Preconditions.checkArgument(strength > 0, "Knockback strength must be > 0");
++        getHandle().knockback(strength, directionX, directionZ);
++    };
+     // Paper end
+ }