import java.util.Iterator; import java.util.NoSuchElementException;

public class LinkedListWrapper { public static interface List extends Iterable { public int size(); public boolean isEmpty(); public boolean isMember(E e); public int firstIndexOf(E e); public int lastIndexOf(E e);

public void add(E e); public void add(E e, int index); public E get(int index); public E remove(int index); public boolean remove(E e); public int removeAll(E e); public E replace(int index, E newElement); public void clear(); public Object[] toArray(); public void addBefore(E e, E f);

} public static class SinglyLinkedList implements List {

@SuppressWarnings("hiding") private class SinglyLinkedListIterator implements Iterator{ private Node nextNode;

@SuppressWarnings("unchecked") public SinglyLinkedListIterator() { this.nextNode = (Node) header.getNext(); } @Override public boolean hasNext() { return nextNode != null; }

@Override public E next() { if (this.hasNext()) { E result = this.nextNode.getElement(); this.nextNode = this.nextNode.getNext(); return result; } else { throw new NoSuchElementException(); } } } private static class Node { private E element; private Node next; public Node(E element, Node next) { super(); this.element = element; this.next = next; } public Node() { super(); } public E getElement() { return element; } public void setElement(E element) { this.element = element; } public Node getNext() { return next; } public void setNext(Node next) { this.next = next; }

}

private Node header; private int currentSize; public SinglyLinkedList() { this.header = new Node(); this.currentSize = 0; } @Override public int size() { return this.currentSize; }

@Override public boolean isEmpty() { return this.size() == 0; }

@Override public boolean isMember(E e) { return this.firstIndexOf(e) >= 0; }

@Override public int firstIndexOf(E e) { int i = 0; for (Node temp = this.header.getNext(); temp != null; temp = temp.getNext(), ++i) { if (temp.getElement().equals(e)) { return i; } } // not found return -1; }

@Override public void add(E e) { if (this.isEmpty()) { this.header.setNext(new Node(e, null)); this.currentSize++; } else { Nodetemp= this.header.getNext(); while (temp.getNext() != null) { temp = temp.getNext(); } Node newNode = new Node(e, null); temp.setNext(newNode); this.currentSize++; } }

@Override public void add(E e, int index) { if ((index this.currentSize)) { throw new IndexOutOfBoundsException(); } if (index == this.currentSize) { this.add(e); } else { Node temp = null; if (index == 0) { temp = this.header; } else { temp = this.getPosition(index -1); } Node newNode = new Node(); newNode.setElement(e); newNode.setNext(temp.getNext()); temp.setNext(newNode); this.currentSize++; } }

@Override public E get(int position) { if ((position = this.currentSize) { throw new IndexOutOfBoundsException(); } Node temp = this.getPosition(position); return temp.getElement(); }

private Node getPosition(int index){ int currentPosition=0; Node temp = this.header.getNext(); while(currentPosition != index) { temp = temp.getNext(); currentPosition++; } return temp;

} @Override public E remove(int index) { if ((index = this.currentSize)){ throw new IndexOutOfBoundsException(); } else { Node temp = this.header; int currentPosition =0; Node target = null; while (currentPosition != index) { temp = temp.getNext(); currentPosition++; } E result = null; target = temp.getNext(); result = target.getElement(); temp.setNext(target.getNext()); target.setElement(null); target.setNext(null); this.currentSize--; return result; } }

@Override public E replace(int position, E newElement) { if ((position = this.currentSize) { throw new IndexOutOfBoundsException(); } Node temp = this.getPosition(position); E result = temp.getElement(); temp.setElement(newElement); return result; }

@Override public void clear() { while(!this.isEmpty()) { this.remove(0); } }

@Override public Object[] toArray() { Object[] result = new Object[this.size()]; for (int i=0; i

@Override public Iterator iterator() { return new SinglyLinkedListIterator(); }

@Override public int lastIndexOf(E e) { int i = 0, result = -1; for (Node temp = this.header.getNext(); temp != null; temp = temp.getNext(), ++i) { if (temp.getElement().equals(e)) { result = i; } } // not found return result; }

@Override public boolean remove(E e) { int i = this.firstIndexOf(e); if (i

@Override public int removeAll(E e) { int count = 0; while (this.remove(e)) { count++; } return count; }

@Override public void addBefore(E e, E f) { for(int i=0;i

}

} } } }

Consider a member method of the list. ADT named adaBefore. This method receives as parameters two objects e and . The methods adds element f before the first copy of the element e in a list L. Implement this method for the singlyLinkedlist class, For example, if (Ken, Bob, Ron, Apu, Ron), the LaddBefore("Ron"Uim) makel Ken, Bob, Jim, Ron Apu, Ron) YOU MUST IMPLEMENT ANY AUXILIARY FUNCTION THAT YOU MIGHT NEED