buffer-monitor-good

public class Buffer<T> {

    List<T> items;
    private int capacity;

    private Lock canProduce = new ReentrantLock();
    private Lock canConsume= new ReentrantLock();

    public Buffer(int capacity){
        this.items = new ArrayList<>(capacity);
        this.capacity = capacity;
    }

    public synchronized T getItem() throws InterruptedException {
        T item = null;

        while(items.size() == 0)
            wait();

        item = items.remove(items.size() - 1);

        notifyAll();
        return item;
    }

    public synchronized void addItem(T item) throws InterruptedException {
        while (items.size() == capacity)
            wait();

        items.add(item);

        notifyAll();
    }

}