Remove Recipes

[diesieben07]

Read the Javadocs. The entrySet is a view of the map, meaning removing from it will also remove from the Map. And as long as you use the iterator methods to remove you will be fine from ConcurrentModificationExceptions.

[SanAndreaP]

this is the post he made

public static void removeFurnaceRecipe(ItemStack stack) {
         Map recipes = FurnaceRecipes.smelting().getSmeltingList();
         
         Iterator entries = recipes.entrySet().iterator();
         while (entries.hasNext()) {
            
            Entry thisEntry = (Entry) entries.next();
           if (stack.getItem() != null && stack.getItem() == Items.baked_potato) {
               entries.remove();
            }
         }
      }

 

problem 1

if (stack.getItem() != null && stack.getItem() == Items.baked_potato) {

this is testing to see what the item passes to the method is not the item from the recipe, in the very first post he actually had this bit correct

 

problem 2

entries.remove();

is removing it from the Iterator not the Recipe HashMap it should be

recipes.remove(thisEntry.getKey());

 

just as a note, removing the items from a hashmap can cause errors while reading through the Map

I would recommend instead of removing immediately create a list of items to remove then remove them after scanning the list

 

like this

public static void removeFurnaceRecipe(ItemStack stack) {
        Map<ItemStack, ItemStack> recipes = FurnaceRecipes.smelting().getSmeltingList();
        LinkedList<ItemStack> remlist=new LinkedList<ItemStack>();
        Iterator<Entry<ItemStack, ItemStack>> entries = recipes.entrySet().iterator();
        while (entries.hasNext()) {
           Entry<ItemStack, ItemStack> thisEntry = (Entry<ItemStack, ItemStack>) entries.next();
           if (ItemStack.areItemStacksEqual(thisEntry.getValue(), stack)) {
        	   remlist.add(thisEntry.getKey());
           }
        }
        for(ItemStack rm:remlist) recipes.remove(rm);
     }

 

You know that updating the iterator (e.g. removing an element) updates the list/map as well!?

 

That's the point of an Iterator... To modify the list/map while iterating through it and not cause a ConcurrentModificationException or needing complicated workaround code.

 

Your code is just overcomplicating the thing the Iterator is there for...

 

This is my code using the iterator to remove elements, it works:

https://github.com/SanAndreasP/ClaySoldiersMod/blob/master/java/de/sanandrew/mods/claysoldiers/entity/EntityClayMan.java#L126-L137

 

 

EDIT: Also what diesieben07 said (I should read the 2nd page before posting <.<)