Creating a fixed-size Stack

Question

I want to create a Stack in Java, but fix the size. For example, create a new Stack, set the size to 10, then as I push items to the stack it fills up and when it fills up t

Answer 1

You can use LinkedHashMap and override its removeEldestEntry method:

public class FixedStack extends LinkedHashMap {

    private final int capacity;

    public FixedStack(int capacity) {
        this.capacity = capacity;
    }

    @Override
    protected boolean removeEldestEntry(final Map.Entry eldest) {
        return super.size() > capacity;
    }
}

And to test it:

    public static void main(String[] args) {

        FixedStack stack = new FixedStack(10);

        long added = 0;
        for (Locale locale : Locale.getAvailableLocales()) {
            if (locale.getDisplayCountry().length() > 0) {
                stack.put(added, locale.getDisplayCountry());
                System.out.println(locale.getDisplayCountry());
                added++;
            }
        }
        System.out.println(String.format(">>>>>>>>> %s added",
                added));
        Iterator> iterator = stack.entrySet().iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next().getValue());
        }
    }

You just have to decide what you want to use as the key, I used a simple counter in the example.