lonia_

Hi, At first, I speak french, so I'm sorry for my bad english... I'm creating a small mod and I want to create a double output furnace. I tried the code below, it works fine, but if I try to take an item out of my custom furnace while another one is "burning", my game crashs and says me java.lang.NullPointerException: Ticking block entity at lonia.nextgen.tileentities.machinecellextractor.TileEntityCellExtractor.hasValidOutputs(TileEntityCellExtractor.java:278) at lonia.nextgen.tileentities.machinecellextractor.TileEntityCellExtractor.canSmelt(TileEntityCellExtractor.java:204) at lonia.nextgen.tileentities.machinecellextractor.TileEntityCellExtractor.updateEntity(TileEntityCellExtractor.java:211) at net.minecraft.world.World.updateEntities(World.java:2160) at net.minecraft.world.WorldServer.updateEntities(WorldServer.java:515) at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:703) at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:614) at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:485) at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:752) TileEntity Class package lonia.nextgen.tileentities.machinecellextractor; import lonia.nextgen.common.ModItems; import lonia.nextgen.tileentities.machinecube.MachineCubeRecipes; import net.minecraft.entity.player.EntityPlayer; import net.minecraft.init.Items; import net.minecraft.inventory.IInventory; import net.minecraft.item.ItemStack; import net.minecraft.nbt.NBTTagCompound; import net.minecraft.nbt.NBTTagList; import net.minecraft.tileentity.TileEntity; public class TileEntityCellExtractor extends TileEntity implements IInventory { private ItemStack[] contents = new ItemStack[3]; private int workingTime = 0; private int workingTimeNeeded = 200; private ItemStack skinsheep = new ItemStack(ModItems.itemSkinPiece,1,1); private ItemStack cellsheep = new ItemStack(ModItems.itemCell, 1, 1); private ItemStack emptyskin = new ItemStack(ModItems.itemSkinPiece, 1, 0); ItemStack itemstack1 = null; ItemStack itemstack2 = null; public void writeToNBT(NBTTagCompound compound) { super.writeToNBT(compound); NBTTagList nbttaglist = new NBTTagList(); for (int i = 0; i < this.contents.length; i++) { if (this.contents[i] != null) { NBTTagCompound nbttagcompound1 = new NBTTagCompound(); nbttagcompound1.setByte("Slot", (byte)i); this.contents[i].writeToNBT(nbttagcompound1); nbttaglist.appendTag(nbttagcompound1); } } compound.setTag("Items", nbttaglist); compound.setShort("workingTime", (short)this.workingTime); compound.setShort("workingTimeNeeded", (short)this.workingTimeNeeded); } public void readFromNBT(NBTTagCompound compound) { super.readFromNBT(compound); NBTTagList nbttaglist = compound.getTagList("Items", 10); this.contents = new ItemStack[this.getSizeInventory()]; for (int i = 0; i < nbttaglist.tagCount(); i++) { NBTTagCompound nbttagcompound1 = nbttaglist.getCompoundTagAt(i); int j = nbttagcompound1.getByte("Slot") & 255; if (j >= 0 && j < this.contents.length) { this.contents[j] = ItemStack.loadItemStackFromNBT(nbttagcompound1); } } this.workingTime = compound.getShort("workingTime"); this.workingTimeNeeded = compound.getShort("workingTimeNeeded"); } @Override public int getSizeInventory() { return this.contents.length; } @Override public ItemStack getStackInSlot(int slotIndex) { return this.contents[slotIndex]; } @Override public ItemStack decrStackSize(int slotIndex, int amount) { if (this.contents[slotIndex] != null) { ItemStack itemstack; if (this.contents[slotIndex].stackSize <= amount) { itemstack = this.contents[slotIndex]; this.contents[slotIndex] = null; this.markDirty(); return itemstack; } else { itemstack = this.contents[slotIndex].splitStack(amount); if (this.contents[slotIndex].stackSize == 0) { this.contents[slotIndex] = null; } this.markDirty(); return itemstack; } } else { return null; } } @Override public ItemStack getStackInSlotOnClosing(int slotIndex) { if (this.contents[slotIndex] != null) { ItemStack itemstack = this.contents[slotIndex]; this.contents[slotIndex] = null; return itemstack; } else { return null; } } @Override public void setInventorySlotContents(int slotIndex, ItemStack stack) { this.contents[slotIndex] = stack; if (stack != null && stack.stackSize > this.getInventoryStackLimit()) { stack.stackSize = this.getInventoryStackLimit(); } this.markDirty(); } @Override public String getInventoryName() { return "tile.machineCellExtractor"; } @Override public boolean hasCustomInventoryName() { return false; } @Override public int getInventoryStackLimit() { return 64; } @Override public boolean isUseableByPlayer(EntityPlayer player) { return this.worldObj.getTileEntity(this.xCoord, this.yCoord, this.zCoord) != this ? false : player.getDistanceSq((double)this.xCoord + 0.5D, (double)this.yCoord + 0.5D, (double)this.zCoord + 0.5D) <= 64.0D; } @Override public void openInventory() { } @Override public void closeInventory() { } @Override public boolean isItemValidForSlot(int slot, ItemStack stack) { return slot == 3 ? false : true; } public boolean isBurning() { return this.workingTime > 0; } public boolean canSmelt() { if (this.contents[0] == null) { return false; } else { if (this.contents[0].isItemEqual(skinsheep)) { itemstack1 = cellsheep; itemstack2 = emptyskin; } if (itemstack1 == null) return false; if (itemstack2 == null) return false; return this.hasValidOutputs(); } } public void updateEntity() { if(this.isBurning() && this.canSmelt()) { this.workingTime++; } if(this.canSmelt() && !this.isBurning()) { this.workingTime = 1; } if (this.canSmelt() && this.workingTime == this.workingTimeNeeded) { this.smeltItem(); this.workingTime = 0; } if(!this.canSmelt()) { this.workingTime = 0; } } public void smeltItem() { if (this.canSmelt()) { if (this.contents[1] == null) { this.contents[1] = itemstack1.copy(); } else if (this.contents[1].getItem() == itemstack1.getItem()) { this.contents[1].stackSize += itemstack1.stackSize; } if (this.contents[2] == null) { this.contents[2] = itemstack2.copy(); } else if (this.contents[2].getItem() == itemstack2.getItem()) { this.contents[2].stackSize += itemstack2.stackSize; } this.contents[0].stackSize--; if (this.contents[0].stackSize <= 0) { this.contents[0] = null; } } } public boolean hasValidOutputs() { if (itemstack1 == null || itemstack2 == null) return false; if (this.contents[1] == null && this.contents[2] == null) return true; if (!this.contents[1].isItemEqual(itemstack1)) return false; if (!this.contents[2].isItemEqual(itemstack2)) return false; int result1 = contents[1].stackSize + itemstack1.stackSize; int result2 = contents[2].stackSize + itemstack2.stackSize; return (result2 <= getInventoryStackLimit() && result2 <= this.contents[2].getMaxStackSize()) || (result1 <= getInventoryStackLimit() && result1 <= this.contents[1].getMaxStackSize()); } } Thank you for your help.