Software-DataStructure 三年一直迷糊的链表

 1 public final class LinkedBag<T> implements BagInterface<T>{
 2 
 3     private Node firstNode;
 4     private int numberOfEntries;
 5 
 6     public LinkedBag() {
 7         firstNode = null;
 8         numberOfEntries = 0;
 9     } // end default constructor
10 
11     private class Node // private inner class
12     {
13         private T data; // Entry in bag
14         private Node next; // Link to next node
15 
16         private Node(T dataPortion)
17         {
18             this(dataPortion, null);
19         } // end constructor
20 
21         private Node(T dataPortion, Node nextNode)
22         {
23             data = dataPortion;
24             next = nextNode;
25         } // end constructor
26 
27         private T getData(){
28             return data;
29         }
30 
31         private void setData(T newData){
32             data = newData;
33         }
34 
35         private Node getNextNode(){
36             return next;
37         }
38 
39         private void setNextNode(Node nextNode){
40             next = nextNode;
41         }
42     }
43 
44     /** Adds a new entry to this bag.
45      * @param newEntry  The object to be added as a new entry.
46      *                  @return True
47      */
48     public boolean add(T newEntry) // OutOfMemoryError possible
49     {
50         // Add to beginning of chain.
51         Node newNode = new Node(newEntry);
52         //newNode.next = firstNode; // Make new node reference rest of chain.
53                                     //(first node is null if chain is empty)
54         newNode.setNextNode(firstNode);
55 
56         firstNode = newNode;
57         numberOfEntries++;
58 
59         return true;
60     }