Make CraftMinecartHopper work as InventoryHolder. Adds BUKKIT-3796

src/main/java/org/bukkit/craftbukkit/entity/CraftHumanEntity.java

@@ -4,6 +4,7 @@ import java.util.Set;
 
 import net.minecraft.server.Container;
 import net.minecraft.server.EntityHuman;
+import net.minecraft.server.EntityMinecartHopper;
 import net.minecraft.server.EntityPlayer;
 import net.minecraft.server.Packet100OpenWindow;
 import net.minecraft.server.Packet101CloseWindow;
@@ -221,6 +222,8 @@ public class CraftHumanEntity extends CraftLivingEntity implements HumanEntity {
         case HOPPER:
             if (craftinv.getInventory() instanceof TileEntityHopper) {
                 getHandle().openHopper((TileEntityHopper) craftinv.getInventory());
+            } else if (craftinv.getInventory() instanceof EntityMinecartHopper) {
+                getHandle().openMinecartHopper((EntityMinecartHopper) craftinv.getInventory());
             }
             break;
         case CREATIVE:

src/main/java/org/bukkit/craftbukkit/entity/CraftMinecartHopper.java

@@ -3,20 +3,29 @@ package org.bukkit.craftbukkit.entity;
 import net.minecraft.server.EntityMinecartHopper;
 
 import org.bukkit.craftbukkit.CraftServer;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
 import org.bukkit.entity.EntityType;
 import org.bukkit.entity.minecart.HopperMinecart;
+import org.bukkit.inventory.Inventory;
 
 final class CraftMinecartHopper extends CraftMinecart implements HopperMinecart {
+    private final CraftInventory inventory;
+
     CraftMinecartHopper(CraftServer server, EntityMinecartHopper entity) {
         super(server, entity);
+        inventory = new CraftInventory(entity);
     }
 
     @Override
     public String toString() {
-        return "CraftMinecartHopper";
+        return "CraftMinecartHopper{" + "inventory=" + inventory + '}';
     }
 
     public EntityType getType() {
         return EntityType.MINECART_HOPPER;
     }
+
+    public Inventory getInventory() {
+        return inventory;
+    }
 }

src/main/java/org/bukkit/craftbukkit/inventory/CraftInventory.java

@@ -6,6 +6,7 @@ import java.util.ListIterator;
 
 import net.minecraft.server.ContainerAnvilInventory;
 import net.minecraft.server.ContainerEnchantTableInventory;
+import net.minecraft.server.IHopper;
 import net.minecraft.server.IInventory;
 import net.minecraft.server.InventoryCrafting;
 import net.minecraft.server.InventoryEnderChest;
@@ -15,7 +16,6 @@ import net.minecraft.server.TileEntityBeacon;
 import net.minecraft.server.TileEntityBrewingStand;
 import net.minecraft.server.TileEntityDispenser;
 import net.minecraft.server.TileEntityFurnace;
-import net.minecraft.server.TileEntityHopper;
 
 import org.apache.commons.lang.Validate;
 import org.bukkit.entity.HumanEntity;
@@ -445,7 +445,7 @@ public class CraftInventory implements Inventory {
             return InventoryType.BEACON;
         } else if (inventory instanceof ContainerAnvilInventory) {
             return InventoryType.ANVIL;
-        } else if (inventory instanceof TileEntityHopper) {
+        } else if (inventory instanceof IHopper) {
             return InventoryType.HOPPER;
         } else {
             return InventoryType.CHEST;