I had an idea for a food mod where I want to restrict what containers can hold food. For example I want to restrict normal chests from storing food related items for examples let say bread. Instead bread could only be stored in a food storage box.

 

How could I change make this possible? I would image I would need to use some access transformers or reflection to modify base classes so wooden chests and such would be modified. But how would you actually filter items? Check the ItemStack when placed inside or something and see if it is allowed to be there?

 

Am I close?

A few things... custom container/slot classes would be easiest, via Is ItemValidForSlot, for example. As for replacing vanilla blocks, its a bit more difficult, but you are on the right track. There are few containers automatically placed in the world, I find it easier to hijack a Block placing event and substitute the vanilla block being placed with a custom class. Check the vanilla classes, like maybe furnace, as it display ISidedInventory and some of the functions you would override to filter items.

Ok now just clarify when you mean a block placing event... you are referring to the player placing the block on the ground? Or the world generator placing the block in the world?

Ok now just clarify when you mean a block placing event... you are referring to the player placing the block on the ground? Or the world generator placing the block in the world?

 

This is just a method I chose to use to override vanilla tnt - doesn't mean its the best idea - but I subscribed to PlayerInteract event and intercepted a player placing the block on the ground.

 

public class BuildEventHook {	

@SubscribeEvent
public void onClick(PlayerInteractEvent event) {


	if (event.action == event.action.RIGHT_CLICK_BLOCK) {



		if(!event.world.isRemote){
			if(event.entityPlayer.inventory.mainInventory[event.entityPlayer.inventory.currentItem] != null &&
					event.entityPlayer.inventory.mainInventory[event.entityPlayer.inventory.currentItem].getItem() == Item.getItemFromBlock(Blocks.tnt)){
				int i = event.face;
				int x = event.x;
				int y = event.y;
				int z = event.z;
				boolean can = false;

				// bottom top north south west east
				if(i == 0){
					y--;
				}
				else if(i == 1){
					y++;
				}
				else if(i == 2){
					z--;
				}
				else if(i == 3){
					z++;
				}
				else if(i == 4){
					x--;
				}
				else if(i == 5){
					x++;
				}

				if(event.world.isAirBlock(x, y, z))
					can = true;

				List l = event.world.getEntitiesWithinAABB(
						Entity.class,
						AxisAlignedBB.getBoundingBox(
								(double) x,
								(double) y,
								(double) z,
								(double) x + 1.0d,
								(double) y + 1.0d,
								(double) z + 1.0d));
				if(l.size() > 0)
					can = false;

				if(can){
					event.world.setBlock(x, y, z, IFaction.NewTNT);		
					event.world.notifyBlockOfNeighborChange(x, y, z, IFaction.NewTNT);
				}
				event.setCanceled(true);
			}
		}
	}

}	

}

hmmm I think this gives me an idea at least. I still gotta get some base mod code going so I can flesh out the idea. But this should help me a little bit. Thanks!