AbstractInventory.java

package crazypants.enderio.machine.invpanel.server;

import net.minecraft.item.ItemStack;

abstract class AbstractInventory {
  static final SlotKey[] NO_SLOTS = new SlotKey[0];
  SlotKey[] slotKeys = NO_SLOTS;

  protected void setEmpty(InventoryDatabaseServer db) {
    if (slotKeys.length != 0) {
      reset(db, 0);
    }
  }

  protected void reset(InventoryDatabaseServer db, int count) {
    for (SlotKey slotKey : slotKeys) {
      if(slotKey != null) {
        slotKey.remove(db);
      }
    }
    slotKeys = new SlotKey[count];
  }

  protected void updateSlot(InventoryDatabaseServer db, int slot, ItemStack stack) {
    if (stack == null) {
      emptySlot(db, slot);
    } else {
      updateSlot(db, slot, stack, stack.stackSize);
    }
  }

  protected void updateSlot(InventoryDatabaseServer db, int slot, ItemStack stack, int count) {
    SlotKey slotKey = slotKeys[slot];
    ItemEntry current = slotKey != null ? slotKey.item : null;
    ItemEntry key = db.lookupItem(stack, current, true);
    if (key != current) {
      updateSlotKey(db, slot, slotKey, key, count);
    } else if (slotKey != null && slotKey.count != count) {
      slotKey.count = count;
      db.entryChanged(current);
    }
  }

  protected void emptySlot(InventoryDatabaseServer db, int slot) {
    SlotKey slotKey = slotKeys[slot];
    if (slotKey != null) {
      slotKey.remove(db);
      slotKeys[slot] = null;
    }
  }

  private void updateSlotKey(InventoryDatabaseServer db, int slot, SlotKey slotKey, ItemEntry key, int count) {
    if (slotKey != null) {
      slotKey.remove(db);
      slotKey = null;
    }
    if (key != null)  {
      slotKey = new SlotKey(this, slot, key, count);
      key.addSlot(slotKey);
      db.entryChanged(key);
    }
    slotKeys[slot] = slotKey;
  }

  protected void updateCount(InventoryDatabaseServer db, int slot, ItemEntry entry, int count) {
    SlotKey slotKey = slotKeys[slot];
    if (slotKey != null && slotKey.count != count && slotKey.item == entry) {
      if (count == 0) {
        slotKey.remove(db);
        slotKeys[slot] = null;
      } else {
        slotKey.count = count;
        db.entryChanged(slotKey.item);
      }
    }
  }

  abstract int scanInventory(InventoryDatabaseServer db);

  abstract int extractItem(InventoryDatabaseServer db, ItemEntry entry, int slot, int count);

}