Best way to do a Master List of multiple List<ItemStack>

[HalestormXV]

So I have some Lists that have multiple different ItemStacks in it. I am curious as to what the best way of taking all these Lists and compiling them into one MasterList so that I can iterate through it without having to use each List's getter methods. If anyone has some examples or samples of where they may have or how to do this I'd appreciate it. The current code works fine, but the current code uses each Lists's getter method and checks agains that which for now is okay, but once more combinations start ariving have to check multiple getter methods would be rather troublesome. Here is the code:

https://hastebin.com/howesativu.java

 

I have been looking into flat but I have never used it, am unfamilar with it and am not sure if that would cause problems. Hence why any examples, samples, or whatever would be most helpful if indeed flat is the best way to do this. Or if there is a much simpler and better way to accomplish this.

 

EDIT

I created the MasterList of the Lists. You can see the code segment here:

/**THIS IS GOING TO BE THE LIST of LISTS CODE SO THAT WE DONT NEED TO CREATE A CHECK FOR EVERY COMBINATION
List<List<ItemStack>> masterList = Stream
    .of(
            new RuneBlade_AbilityCosts().getBlastStrikeI(),
            new RuneBlade_AbilityCosts().getBlastStrikeII(),
            new RuneBlade_AbilityCosts().getWeaknessStrikeI(),
            new RuneBlade_AbilityCosts().getWeaknessStrikeII()
    ).collect(Collectors.toList());
List<ItemStack> flat = masterList.stream().flatMap(List::stream).collect(Collectors.toList());
 **/

So that seems like it is the best way to create a MasterList of all those Lists. Here is the full updated code: https://hastebin.com/eyohexicaz.java

Anyone care to illustrate or show how one would be able to cycle through that MasterList (flat) and pull out each individual list (or perhaps it is a sublist?) and check against it namely in my 

checkRunebladeReagents

method? As you may be able to to see in the method I started attempting to do it but then commented it out because I was breaking stuff.

 

I'm not really looking for just answers, I am more looking for examples or samples/explanations that I can work off of and learn how to manipulate lists within a list. Although if you do have sample code to share I'd love to have a look at that also.

Edited April 21, 2018 by HalestormXV

[HalestormXV]

I knew i had this post somewhere. Just giving it a bump instead of making a whole new post.

[HalestormXV]

Alright so just flatMap on that one then okay. But now how would i check each of those lists, it wouldnt be normal list iteration right? For example index 0 in that map would be a list that contains A,B,C,D and index 1 in that map would be a list that contains 1, 2, 3, 4. So how would I check and pull out the valus from each of those lists? Or would it simply be just normal list iteration?

 

What I am trying to acheive is the following. There is an item that has 4 slots. Based on the items within those 4 slots and the order that those items are in, that weapon is charged with a different ability. For instance in the example above you will notice that blastStrike is

                        new ItemStack(ItemInit.ITEM_RUNE, 2, FIRE_RUNE.getMeta()),
                        new ItemStack(ItemInit.ITEM_RUNE, 1, EARTH_RUNE.getMeta()),
                        new ItemStack(ItemInit.ITEM_RUNE, 1, AIR_RUNE.getMeta())

Those are the requirements for blastStrike. So if a player has those items placed in the correct slots in the correct order their weapon will have a chance to inflict blastStrike on hit. My goal is to rather than create an independent check for every single ability to store all the requirments in the lists, like above, into a masterList and then simply just go through the masterList and see if what is currently in the weapon slots matches an entry in that master list.