Linked Data Structures - Absolute Java - page 819

Display 15.8 A Generic Linked List Class (part 2 of 3)

46 Returns the number of nodes in the list.
47 */
48 public int size( )
49 {
50 int count = 0;
51 Node<T> position = head;
52 while (position != null )
53 {
54 count++;
55 position = position.link;
56 }
57

return count;

58 }

59 public boolean contains(T item)
60 {
61 return (find(item) != null );

62 }
63 /**
64 Finds the first node containing the target item, and returns a
65 reference to that node. If target is not in the list, null is
returned.
66 */
67 private Node find(T target)
68 {
69 Node<T> position = head;
70 T itemAtPosition;
71 while (position != null )
72 {
73 itemAtPosition = position.data;
74 if (itemAtPosition.equals(target))
75 return position;
76 position = position.link;
77 }
78

Type T must have a well-defined
equals for this method to work.

return null ;// target was not found

79 }

80 /**
81 Finds the first node containing the target and returns a reference
82 to the data in that node. If target is not in the list, null is
returned.
83 */
84 public T findData(T target)
85 {
86 Node<T> result = find (target);
87 if (result == null )

88 return null ;

89 else

90 return result.data;

(continued)