Implement Hopper block state and inventory methods. Adds BUKKIT-3749

src/main/java/org/bukkit/craftbukkit/block/CraftBlock.java

@@ -249,6 +249,8 @@ public class CraftBlock implements Block {
             return new CraftFurnace(this);
         case DISPENSER:
             return new CraftDispenser(this);
+        case HOPPER:
+            return new CraftHopper(this);
         case MOB_SPAWNER:
             return new CraftCreatureSpawner(this);
         case NOTE_BLOCK:

src/main/java/org/bukkit/craftbukkit/block/CraftHopper.java

@@ -0,0 +1,35 @@
+package org.bukkit.craftbukkit.block;
+
+import net.minecraft.server.TileEntityHopper;
+import org.bukkit.block.Block;
+import org.bukkit.block.Hopper;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.inventory.Inventory;
+
+public class CraftHopper extends CraftBlockState implements Hopper {
+    private final CraftWorld world;
+    private final TileEntityHopper hopper;
+
+    public CraftHopper(final Block block) {
+        super(block);
+
+        world = (CraftWorld) block.getWorld();
+        hopper = (TileEntityHopper) world.getTileEntityAt(getX(), getY(), getZ());
+    }
+
+    public Inventory getInventory() {
+        return new CraftInventory(hopper);
+    }
+
+    @Override
+    public boolean update(boolean force) {
+        boolean result = super.update(force);
+
+        if (result) {
+            hopper.update();
+        }
+
+        return result;
+    }
+}

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

@@ -10,6 +10,7 @@ import net.minecraft.server.Packet101CloseWindow;
 import net.minecraft.server.TileEntityBrewingStand;
 import net.minecraft.server.TileEntityDispenser;
 import net.minecraft.server.TileEntityFurnace;
+import net.minecraft.server.TileEntityHopper;
 
 import org.bukkit.GameMode;
 import org.bukkit.Location;
@@ -217,6 +218,11 @@ public class CraftHumanEntity extends CraftLivingEntity implements HumanEntity {
         case ENCHANTING:
             openCustomInventory(inventory, player, 4);
             break;
+        case HOPPER:
+            if (craftinv.getInventory() instanceof TileEntityHopper) {
+                getHandle().openHopper((TileEntityHopper)craftinv.getInventory());
+            }
+            break;
         case CREATIVE:
         case CRAFTING:
             throw new IllegalArgumentException("Can't open a " + type + " inventory!");

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

@@ -15,6 +15,7 @@ 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;
@@ -444,6 +445,8 @@ public class CraftInventory implements Inventory {
             return InventoryType.BEACON;
         } else if (inventory instanceof ContainerAnvilInventory) {
             return InventoryType.ANVIL;
+        } else if (inventory instanceof TileEntityHopper) {
+            return InventoryType.HOPPER;
         } else {
             return InventoryType.CHEST;
         }