Core Java linked list
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
public class MyLinkedList implements List{
private Node head;
private int count;
public MyLinkedList(){
head=new Node();
}
private static class Node{
private Object data;
private Node next;
public Node(Object obj){
this.data=obj;
}
public Node(){
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
public Node getNext() {
return next;
}
public void setNext(Node next) {
this.next = next;
}
}
public void add(int index, Object element) {
// 1,判断index是否有效，如果无效则抛出异常。
//2,生成Node，数据域是element
//3，找到待插入的位置
if(index<0 || index >count){
throw new IndexOutOfBoundsException("无效的下标："+index);
}
Node n=new Node(element);
Node p=head;
for(int i=0;i<index;i++){
p=p.next;
}
n.next=p.next;
p.next=n;
count++;
}
public boolean add(Object e) {
add(count,e);
return true;
}
public boolean addAll(Collection c) {
// TODO Auto-generated method stub
return false;
}
public boolean addAll(int index, Collection c) {
// TODO Auto-generated method stub
return false;
}
public void clear() {
count=0;
head.next=null;
}
public boolean contains(Object o) {
Node p=head.next;
while(p!=null){
if(p.data.equals(o)){
return true;
}
p=p.next;
}
return false;
}
public boolean containsAll(Collection c) {
// TODO Auto-generated method stub
return false;
}
public Object get(int index) {
if(index<0 || index >=count){
throw new IndexOutOfBoundsException("无效的下标："+index);
}
Node p=head;
for(int i=0;i<index;i++){
p=p.next;
}
return p.next.data;
}
public int indexOf(Object o) {
Node p=head.next;
int index=0;
while(p!=null){
if(p.data.equals(o)){
return index;
}
p=p.next;
index++;
}
return -1;
}
public boolean isEmpty() {
// ?????????????????
return count==0 && head.next==null;
}
public Iterator iterator() {
return new Iterator(){
Node p=head.next;
public boolean hasNext() {
return p!=null;
}
public Object next() {
Node q=p;
p=p.next;
return q.data;
}
public void remove() {
// ???????????
}
};
}
public int lastIndexOf(Object o) {
Node p=head.next;
int index =-1;
int i=0;
while(p!=null){
if(p.data.equals(o)){
index=i;
}
p=p.next;
i++;
}
return index;
}
public ListIterator listIterator() {
// TODO Auto-generated method stub
return null;
}
public ListIterator listIterator(int index) {
// TODO Auto-generated method stub
return null;
}
public Object remove(int index) {
if(index<0 || index>=count){
throw new IndexOutOfBoundsException("无效的下标："+index);
}
Node p=head;
for(int i=0;i<index;i++){
p=p.next;
}
Node q=p.next;
p.next=q.next;
q.next=null;
return q.data;
}
public boolean remove(Object o) {
int index=indexOf(o);
if(index>=0){
remove(index);
return true;
}
return false;
}
public boolean removeAll(Collection c) {
// TODO Auto-generated method stub
return false;
}
public boolean retainAll(Collection c) {
// TODO Auto-generated method stub
return false;
}
public Object set(int index, Object element) {
if(index<0 || index>=count){
throw new IndexOutOfBoundsException("无效的下标："+index);
}
Node p=head.next;
for(int i=0;i<index;i++){
p=p.next;
}
Object temp=p.data;
p.data=element;
return temp;
}
public int size() {
return count;
}
public List subList(int fromIndex, int toIndex) {
// TODO Auto-generated method stub
return null;
}
public Object[] toArray() {
// TODO Auto-generated method stub
return null;
}
public Object[] toArray(Object[] a) {
// TODO Auto-generated method stub
return null;
}
}