执行此操作的最有效方法

Question

I'm currently working with the Bukkit API, but this has more to do with general Java, so I'm asking here. I have two HashMaps to store data into, and need to be able to compare the two.

public HashMap<Scoreboard, ArrayList<PlayerScore>> lastList = new HashMap<Scoreboard, ArrayList<PlayerScore>>();
public HashMap<Scoreboard, ArrayList<PlayerScore>> currentList = new HashMap<Scoreboard, ArrayList<PlayerScore>>();

I can iterate using while loops, and that works, but there's a problem with this because I then have to iterate through another ArrayList within the loop, and since there are two hashmaps, I end up doing 4 hashmaps in total... This is my current code:

    public void remove(Scoreboard board) {
    Iterator<Entry<Scoreboard, ArrayList<PlayerScore>>> lastIt = lastList.entrySet().iterator();
    Iterator<Entry<Scoreboard, ArrayList<PlayerScore>>> currentIt = currentList.entrySet().iterator();
    while (lastIt.hasNext()) {
        System.out.println("dbg1");
        Entry<Scoreboard, ArrayList<PlayerScore>> nextLast = lastIt.next();
        if (nextLast.getKey().equals(board)) {
            System.out.println("dbg2");
            while (currentIt.hasNext()) {
                Entry<Scoreboard, ArrayList<PlayerScore>> nextCurrent = currentIt.next();

                ArrayList<PlayerScore> lastArray = nextLast.getValue();
                ArrayList<PlayerScore> currentArray = nextCurrent.getValue();

                Iterator<PlayerScore> lastArrayIt = lastArray.iterator();
                Iterator<PlayerScore> currentArrayIt = currentArray.iterator();
                while (lastArrayIt.hasNext()) {
                    System.out.println("dbg3");
                    PlayerScore nextCurrentArray = currentArrayIt.next();

                    while (currentArrayIt.hasNext()) {
                        System.out.println("dbg4");
                        if (!lastArray.contains(nextCurrentArray)) {
                            System.out.println("dbg5");
                            board.resetScores(nextCurrentArray.getString());
                            lastArrayIt.remove();
                            currentArrayIt.remove();
                            break;
                        }
                    }

                    break;
                }

                break;
            }
        }

        break;
    }
}

I know, it's very messy, but I don't really know what else to do for this. The while loops execute so much that the server console is filled with only "dbg4" because it's outputting so fast. This also crashes the server.

Anyone know a better way to do this?

Answer 1

You dont need to iterate over the hashmap. You could just do:

ArrayList<PlayerScore> lastArray = lastList.remove(board);
ArrayList<PlayerScore> currentArray = currentList.remove(board);