Add BlockDropper for diff visibility

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

@@ -0,0 +1,55 @@
+package net.minecraft.server;
+
+public class BlockDropper extends BlockDispenser {
+
+    private final IDispenseBehavior cR = new DispenseBehaviorItem();
+
+    protected BlockDropper(int i) {
+        super(i);
+    }
+
+    protected IDispenseBehavior a(ItemStack itemstack) {
+        return this.cR;
+    }
+
+    public TileEntity b(World world) {
+        return new TileEntityDropper();
+    }
+
+    protected void dispense(World world, int i, int j, int k) {
+        SourceBlock sourceblock = new SourceBlock(world, i, j, k);
+        TileEntityDispenser tileentitydispenser = (TileEntityDispenser) sourceblock.getTileEntity();
+
+        if (tileentitydispenser != null) {
+            int l = tileentitydispenser.j();
+
+            if (l < 0) {
+                world.triggerEffect(1001, i, j, k, 0);
+            } else {
+                ItemStack itemstack = tileentitydispenser.getItem(l);
+                int i1 = world.getData(i, j, k) & 7;
+                IInventory iinventory = TileEntityHopper.getInventoryAt(world, (double) (i + Facing.b[i1]), (double) (j + Facing.c[i1]), (double) (k + Facing.d[i1]));
+                ItemStack itemstack1;
+
+                if (iinventory != null) {
+                    itemstack1 = TileEntityHopper.addItem(iinventory, itemstack.cloneItemStack().a(1), Facing.OPPOSITE_FACING[i1]);
+                    if (itemstack1 == null) {
+                        itemstack1 = itemstack.cloneItemStack();
+                        if (--itemstack1.count == 0) {
+                            itemstack1 = null;
+                        }
+                    } else {
+                        itemstack1 = itemstack.cloneItemStack();
+                    }
+                } else {
+                    itemstack1 = this.cR.a(sourceblock, itemstack);
+                    if (itemstack1 != null && itemstack1.count == 0) {
+                        itemstack1 = null;
+                    }
+                }
+
+                tileentitydispenser.setItem(l, itemstack1);
+            }
+        }
+    }
+}