content: package net.minecraft.inventory;
  
  import net.minecraft.entity.player.EntityPlayer;
  import net.minecraft.entity.player.InventoryPlayer;
  import net.minecraft.item.ItemStack;
  
  public class ContainerHopper extends Container {
      private final IInventory hopperInventory;
  
      public ContainerHopper(InventoryPlayer playerInventory, IInventory hopperInventoryIn, EntityPlayer player) {
          this.hopperInventory = hopperInventoryIn;
          hopperInventoryIn.openInventory(player);
          int i = 51;
  
          for (int j = 0; j < hopperInventoryIn.getSizeInventory(); ++j) {
              this.addSlotToContainer(new Slot(hopperInventoryIn, j, 44 + j * 18, 20));
          }
  
          for (int l = 0; l < 3; ++l) {
              for (int k = 0; k < 9; ++k) {
                  this.addSlotToContainer(new Slot(playerInventory, k + l * 9 + 9, 8 + k * 18, l * 18 + i));
              }
          }
  
          for (int i1 = 0; i1 < 9; ++i1) {
              this.addSlotToContainer(new Slot(playerInventory, i1, 8 + i1 * 18, 58 + i));
          }
      }
  
      public boolean canInteractWith(EntityPlayer playerIn) {
          return this.hopperInventory.isUseableByPlayer(playerIn);
      }
  
      public ItemStack transferStackInSlot(EntityPlayer playerIn, int index) {
          ItemStack itemstack = null;
          Slot slot = this.inventorySlots.get(index);
  
          if (slot != null && slot.getHasStack()) {
              ItemStack itemstack1 = slot.getStack();
              itemstack = itemstack1.copy();
  
              if (index < this.hopperInventory.getSizeInventory()) {
                  if (!this.mergeItemStack(itemstack1, this.hopperInventory.getSizeInventory(), this.inventorySlots.size(), true)) {
                      return null;
                  }
              } else if (!this.mergeItemStack(itemstack1, 0, this.hopperInventory.getSizeInventory(), false)) {
                  return null;
              }
  
              if (itemstack1.stackSize == 0) {
                  slot.putStack(null);
              } else {
                  slot.onSlotChanged();
              }
          }
  
          return itemstack;
      }
  
      public void onContainerClosed(EntityPlayer playerIn) {
          super.onContainerClosed(playerIn);
          this.hopperInventory.closeInventory(playerIn);
      }
  }
  