package listadt;

import java.util.function.Function;

/**
 * This represents an empty node of the generic list implementation.
 */
public class GenericEmptyNode<T> implements GenericListADTNode<T> {
  @Override
  public int count(){return 0;}

  @Override
  public GenericListADTNode<T> addFront(T object) {
    return new GenericElementNode(object,this);
  }

  @Override
  public GenericListADTNode<T> addBack(T object) { return addFront(object);}

  @Override
  public GenericListADTNode<T> add(int index,T object) throws
          IllegalArgumentException {
    if (index==0){
      return addFront(object);
    }
    throw new IllegalArgumentException("Invalid index to add an element");
  }

  @Override
  public GenericListADTNode<T> remove(T object) {
    return this; //cannot remove from nothing!
  }

  @Override
  public T get(int index) throws IllegalArgumentException {
    throw new IllegalArgumentException("Wrong index");
  }

  @Override
  public <R> GenericListADTNode<R> map(Function<T,R> converter) {
    return new GenericEmptyNode();
  }

  @Override
  public String toString() { return "";}
}