001    package net.minecraft.src;
002    
003    import cpw.mods.fml.common.Side;
004    import cpw.mods.fml.common.asm.SideOnly;
005    
006    public class Slot
007    {
008        /** The index of the slot in the inventory. */
009        private final int slotIndex;
010    
011        /** The inventory we want to extract a slot from. */
012        public final IInventory inventory;
013    
014        /** the id of the slot(also the index in the inventory arraylist) */
015        public int slotNumber;
016    
017        /** display position of the inventory slot on the screen x axis */
018        public int xDisplayPosition;
019    
020        /** display position of the inventory slot on the screen y axis */
021        public int yDisplayPosition;
022    
023        public Slot(IInventory par1IInventory, int par2, int par3, int par4)
024        {
025            this.inventory = par1IInventory;
026            this.slotIndex = par2;
027            this.xDisplayPosition = par3;
028            this.yDisplayPosition = par4;
029        }
030    
031        /**
032         * if par2 has more items than par1, onCrafting(item,countIncrease) is called
033         */
034        public void onSlotChange(ItemStack par1ItemStack, ItemStack par2ItemStack)
035        {
036            if (par1ItemStack != null && par2ItemStack != null)
037            {
038                if (par1ItemStack.itemID == par2ItemStack.itemID)
039                {
040                    int var3 = par2ItemStack.stackSize - par1ItemStack.stackSize;
041    
042                    if (var3 > 0)
043                    {
044                        this.onCrafting(par1ItemStack, var3);
045                    }
046                }
047            }
048        }
049    
050        /**
051         * the itemStack passed in is the output - ie, iron ingots, and pickaxes, not ore and wood. Typically increases an
052         * internal count then calls onCrafting(item).
053         */
054        protected void onCrafting(ItemStack par1ItemStack, int par2) {}
055    
056        /**
057         * the itemStack passed in is the output - ie, iron ingots, and pickaxes, not ore and wood.
058         */
059        protected void onCrafting(ItemStack par1ItemStack) {}
060    
061        /**
062         * Called when the player picks up an item from an inventory slot
063         */
064        public void onPickupFromSlot(ItemStack par1ItemStack)
065        {
066            this.onSlotChanged();
067        }
068    
069        /**
070         * Check if the stack is a valid item for this slot. Always true beside for the armor slots.
071         */
072        public boolean isItemValid(ItemStack par1ItemStack)
073        {
074            return true;
075        }
076    
077        /**
078         * Helper fnct to get the stack in the slot.
079         */
080        public ItemStack getStack()
081        {
082            return this.inventory.getStackInSlot(this.slotIndex);
083        }
084    
085        /**
086         * Returns if this slot contains a stack.
087         */
088        public boolean getHasStack()
089        {
090            return this.getStack() != null;
091        }
092    
093        /**
094         * Helper method to put a stack in the slot.
095         */
096        public void putStack(ItemStack par1ItemStack)
097        {
098            this.inventory.setInventorySlotContents(this.slotIndex, par1ItemStack);
099            this.onSlotChanged();
100        }
101    
102        /**
103         * Called when the stack in a Slot changes
104         */
105        public void onSlotChanged()
106        {
107            this.inventory.onInventoryChanged();
108        }
109    
110        /**
111         * Returns the maximum stack size for a given slot (usually the same as getInventoryStackLimit(), but 1 in the case
112         * of armor slots)
113         */
114        public int getSlotStackLimit()
115        {
116            return this.inventory.getInventoryStackLimit();
117        }
118    
119        /**
120         * Decrease the size of the stack in slot (first int arg) by the amount of the second int arg. Returns the new
121         * stack.
122         */
123        public ItemStack decrStackSize(int par1)
124        {
125            return this.inventory.decrStackSize(this.slotIndex, par1);
126        }
127    
128        /**
129         * returns true if this slot is in par2 of par1
130         */
131        public boolean isSlotInInventory(IInventory par1IInventory, int par2)
132        {
133            return par1IInventory == this.inventory && par2 == this.slotIndex;
134        }
135    
136        @SideOnly(Side.CLIENT)
137    
138        /**
139         * Returns the icon index on items.png that is used as background image of the slot.
140         */
141        public int getBackgroundIconIndex()
142        {
143            return -1;
144        }
145    }