Implement Dropper interface. Adds BUKKIT-3750

src/main/java/net/minecraft/server/BlockDropper.java

@@ -16,7 +16,7 @@ public class BlockDropper extends BlockDispenser {
         return new TileEntityDropper();
     }
 
-    protected void dispense(World world, int i, int j, int k) {
+    public void dispense(World world, int i, int j, int k) { // CraftBukkit - protected -> public
         SourceBlock sourceblock = new SourceBlock(world, i, j, k);
         TileEntityDispenser tileentitydispenser = (TileEntityDispenser) sourceblock.getTileEntity();
 

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 DROPPER:
+            return new CraftDropper(this);
         case HOPPER:
             return new CraftHopper(this);
         case MOB_SPAWNER:

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

@@ -0,0 +1,50 @@
+package org.bukkit.craftbukkit.block;
+
+import net.minecraft.server.BlockDropper;
+import net.minecraft.server.TileEntityDropper;
+
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.block.Dropper;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.inventory.CraftInventory;
+import org.bukkit.inventory.Inventory;
+
+public class CraftDropper extends CraftBlockState implements Dropper {
+    private final CraftWorld world;
+    private final TileEntityDropper dropper;
+
+    public CraftDropper(final Block block) {
+        super(block);
+
+        world = (CraftWorld) block.getWorld();
+        dropper = (TileEntityDropper) world.getTileEntityAt(getX(), getY(), getZ());
+    }
+
+    public Inventory getInventory() {
+        return new CraftInventory(dropper);
+    }
+
+    public void drop() {
+        Block block = getBlock();
+
+        synchronized (block) {
+            if (block.getType() == Material.DROPPER) {
+                BlockDropper drop = (BlockDropper) net.minecraft.server.Block.DROPPER;
+
+                drop.dispense(world.getHandle(), getX(), getY(), getZ());
+            }
+        }
+    }
+
+    @Override
+    public boolean update(boolean force) {
+        boolean result = super.update(force);
+
+        if (result) {
+            dropper.update();
+        }
+
+        return result;
+    }
+}

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

@@ -15,6 +15,7 @@ import net.minecraft.server.PlayerInventory;
 import net.minecraft.server.TileEntityBeacon;
 import net.minecraft.server.TileEntityBrewingStand;
 import net.minecraft.server.TileEntityDispenser;
+import net.minecraft.server.TileEntityDropper;
 import net.minecraft.server.TileEntityFurnace;
 
 import org.apache.commons.lang.Validate;
@@ -423,10 +424,13 @@ public class CraftInventory implements Inventory {
     }
 
     public InventoryType getType() {
+        // Thanks to Droppers extending Dispensers, order is important.
         if (inventory instanceof InventoryCrafting) {
             return inventory.getSize() >= 9 ? InventoryType.WORKBENCH : InventoryType.CRAFTING;
         } else if (inventory instanceof PlayerInventory) {
             return InventoryType.PLAYER;
+        } else if (inventory instanceof TileEntityDropper) {
+            return InventoryType.DROPPER;
         } else if (inventory instanceof TileEntityDispenser) {
             return InventoryType.DISPENSER;
         } else if (inventory instanceof TileEntityFurnace) {