(Test MyLinkedList) Design and write a complete test program to test if the MyLinkedList class in Listing 24.6 meets all requirements.

1 public class MyLinkedList extends MyAbstractList {

2 private Node head, tail; 3 4 /** Create a default list */ 5 public MyLinkedList() { 6 } 7 8 /** Create a list from an array of objects */ 9 public MyLinkedList(E[] objects) { 10 super(objects); 11 } 12 13 /** Return the head element in the list */ 14 public E getFirst() { 15 if (size == 0) { 16 return null; 17 } 18 else { 19 return head.element; 20 } 21 } 22 23 /** Return the last element in the list */ 24 public E getLast() { 25 if (size == 0) { 26 return null; 27 } 28 else { 29 return tail.element; 30 } 31 } 32 33 /** Add an element to the beginning of the list */ 34 public void addFirst(E e) { 35 // Implemented in Section 24.4.3.1, so omitted here 36 } 37 38 /** Add an element to the end of the list */ 39 public void addLast(E e) { 40 // Implemented in Section 24.4.3.2, so omitted here 41 } 42 43 @Override /** Add a new element at the specified index 44 * in this list. The index of the head element is 0 */ 45 public void add(int index, E e) { 46 // Implemented in Section 24.4.3.3, so omitted here 47 } 48 49 /** Remove the head node and 50 * return the object that is contained in the removed node. */ 51 public E removeFirst() { 52 // Implemented in Section 24.4.3.4, so omitted here /** Remove the last node and 56 * return the object that is contained in the removed node. */ 57 public E removeLast() { 58 // Implemented in Section 24.4.3.5, so omitted here 59 } 60 61 @Override /** Remove the element at the specified position in this 62 * list. Return the element that was removed from the list. */ 63 public E remove(int index) { 64 // Implemented earlier in Section 24.4.3.6, so omitted here 65 } 66 67 @Override 68 public String toString() { 69 StringBuilder result = new StringBuilder("["); 70 71 Node current = head; 72 for (int i = 0; i < size; i++) { 73 result.append(current.element); 74 current = current.next; 75 if (current != null) { 76 result.append(", "); // Separate two elements with a comma 77 } 78 else { 79 result.append("]"); // Insert the closing ] in the string 80 } 81 } 82 83 return result.toString(); 84 } 85 86 @Override /** Clear the list */ 87 public void clear() { 88 size = 0; 89 head = tail = null; 90 } 91 92 @Override /** Return true if this list contains the element e */ 93 public boolean contains(E e) { 94 System.out.println("Implementation left as an exercise"); 95 return true; 96 } 97 98 @Override /** Return the element at the specified index */ 99 public E get(int index) { 100 System.out.println("Implementation left as an exercise"); 101 return null; 102 } 103 104 @Override /** Return the index of the head matching element 105 * in this list. Return -1 if no match. */ 106 public int indexOf(E e) { 107 System.out.println("Implementation left as an exercise"); 108 return 0; 109 } 110 111 @Override /** Return the index of the last matching element 112 * in this list. Return -1 if no match. */ 113 public int lastIndexOf(E e) { 114 System.out.println("Implementation left as an exercise"); 115 return 0; 116 } 117 118 @Override /** Replace the element at the specified position 119 * in this list with the specified element. */ 120 public E set(int index, E e) { 121 System.out.println("Implementation left as an exercise"); 122 return null; 123 } 124 125 @Override /** Override iterator() defined in Iterable */ 126 public java.util.Iterator iterator() { 127 return new LinkedListIterator(); 128 } 129 130 private class LinkedListIterator 131 implements java.util.Iterator { 132 private Node current = head; // Current index 133 134 @Override 135 public boolean hasNext() { 136 return (current != null); 137 } 138 139 @Override 140 public E next() { 141 E e = current.element; 142 current = current.next; 143 return e; 144 } 145 146 @Override 147 public void remove() { 148 System.out.println("Implementation left as an exercise"); 149 } 150 } 151 152 // This class is only used in LinkedList, so it is private. 153 // This class does not need to access any 154 // instance members of LinkedList, so it is defined static. 155 private static class Node { 156 E element; 157 Node next; 158 159 public Node(E element) { 160 this.element = element;