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

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;
+    }
+}