package basictype;
import java.util.Iterator;

public class LinkedBag<T> extends Bag<T> {
  private class Link {
    T element;
    Link next;
    
    Link(T element, Link next) {
      this.element = element;
      this.next = next;
    }
  }
  
  private Link last_added;
  private int size;
  
  public LinkedBag() {
    this.size = 0;
    this.last_added = null;
  }
  
  @Override
  public void add(T item) {
    this.last_added = new Link(item, this.last_added);
    this.size++;
  }
    
  @Override
  public int size() {
    return this.size;
  }
  
  @Override
  public Iterator<T> iterator() {
    return new LinkedBagIterator();
  }

  private class LinkedBagIterator implements Iterator <T> {
    private Link currentLink = LinkedBag.this.last_added;
    
    @Override
    public boolean hasNext() {
      return this.currentLink != null ;
    }
    
    @Override
    public T next() {
      T result = this.currentLink.element;
      this.currentLink = this.currentLink.next;
      return result;
    }

    @Override
    public void remove() {
      // Don't do anything, removing items from a bag is not allowed!
    }
  }
  
  private static final String[] defaultArgs = {
    "un", "deux", "trois", "quatre", "cinq",
    "six", "sept", "huit", "neuf", "dix",
    "onze", "douze", "treize", "quatorze", "quinze"
  };
  
  public static void main(String[] args) {
    String[] items = args;
    if (items.length == 0) { // No arguments -> use default sample of items
      items = defaultArgs;
    }
    Bag<String> b = new LinkedBag<String>();
    for(String item: items) {
      b.add(item);
    }
    
    System.out.println("# Iterate");
    for(String item : b) {
      System.out.println(item);
    }
  }

}