JAVA类库LinkList的基本实现

写完调试了好久，边界不好处理，详细的请看JDK类库，以下只是基本实现：

import java.util.Iterator;/** * 类名：MyLinkedList 说明：LinkedList的基本实现 */public class MyLinkedList<AnyType> implements Iterable {private int theSize = 0;private int modCount = 0;private Node<AnyType> beginMarker;private Node<AnyType> endMarker;private static class Node<AnyType> {public Node(AnyType data, Node<AnyType> prev, Node<AnyType> next) {this.data = data;this.prev = prev;this.next = next;}public AnyType data;public Node<AnyType> prev;public Node<AnyType> next;}public MyLinkedList() {clear();}public void clear() {beginMarker = new Node<AnyType>(null, null, null);endMarker = new Node<AnyType>(null, beginMarker, null);beginMarker.next = endMarker;theSize = 0;modCount++;}public boolean isEmpty() {return theSize == 0;}public int size() {return theSize;}public boolean add(AnyType x) {add(theSize, x);return true;}public void add(int index, AnyType x) {addBefore(getNode(index), x);}public AnyType get(int index) {return getNode(index).data;}private Node<AnyType> getNode(int index) {if (index < 0 || index > theSize)throw new IndexOutOfBoundsException();Node<AnyType> p;if (index < size() / 2) {p = beginMarker.next;for (int i = 0; i < index; i++) {p = p.next;}} else {p = endMarker;for (int i = theSize; i > index; i--)p = p.prev;}return p;}private void addBefore(Node<AnyType> p, AnyType x) {Node<AnyType> newNode = new Node(x, p.prev, p);newNode.prev.next = newNode;p.prev = newNode;theSize++;modCount++;}private AnyType remove(Node<AnyType> p) {AnyType removed = p.data;p.prev.next = p.next;p.next.prev = p.prev;theSize--;modCount++;return removed;}public AnyType set(int index, AnyType x) {AnyType old = getNode(index).data;getNode(index).data = x;return old;}public AnyType remove(int index) {return remove(getNode(index));}@Overridepublic Iterator iterator() {// TODO Auto-generated method stubreturn new Iterator() {//匿名内部类实现，jdk里是返回重新写的一个private类。private Node<AnyType> current = beginMarker.next;private int expectedModCount = modCount;private boolean okToRemove = false;public boolean hasNext() {return current != endMarker;}public AnyType next() {if (modCount != expectedModCount) {throw new java.util.ConcurrentModificationException();}if (!hasNext())throw new java.util.NoSuchElementException();AnyType d = current.data;current = current.next;okToRemove = true;return d;}public void remove() {if (modCount != expectedModCount) {throw new java.util.ConcurrentModificationException();}if (!okToRemove)throw new IllegalStateException();MyLinkedList.this.remove(current.prev);okToRemove = false;expectedModCount++;}};}public String toString() {String s = new String();for (int i = 0; i < theSize; i++)s += get(i) + " ";return s;}/** * 方法名：MyLinkedList.java 说明：测试 */public static void main(String[] args) {// TODO Auto-generated method stubMyLinkedList<Integer> list = new MyLinkedList();list.add(1);list.add(2);list.add(3);list.add(4);list.add(5);System.out.println(list);list.remove(1);System.out.println(list);list.set(1, 2);System.out.println(list);Iterator ite = list.iterator();while (ite.hasNext()) {System.out.println(ite.next() + " ");}}}