容易_单链表

package sunfa;

import java.util.Iterator;

/**
 * 单链表
 * 
 * @author Administrator
 * 
 */
public class SingleLinkedList {
	public static void main(String[] args) {
		SingleLinkedList link = new SingleLinkedList();
		for (int i = 10; i < 20; i++) {
			link.add(i);
		}
		System.out.println("list:");
		Iterator it = link.iterator();
		while (it.hasNext()) {
			System.out.println(it.next());
		}
		System.out.println("getFirst:" + link.getFirst());
		System.out.println("getLast:" + link.getLast());
		link.remove(13);
		link.remove(17);
		System.out.println("删除后");
		it = link.iterator();
		while (it.hasNext()) {
			System.out.println(it.next());
		}
	}

	private Node head = new Node(null, null);
	private Node tail = null;

	public SingleLinkedList() {
		head.next = tail;
	}

	public Object getFirst() {
		if (head.next != null)
			return head.next.element;
		return null;
	}

	public Object getLast() {
		if (tail == null) {
			return null;
		}
		return tail.getElement();
	}

	public void add(Object o) {
		Node node = new Node(o, null);
		if (tail == null)
			head.next = node;
		else
			tail.next = node;
		tail = node;
	}

	public Object remove(Object o) {
		for (Node e = head.next; e != head;) {
			Node current = e;
			e = e.next;
			if (e.element == o) {
				current.next = e.next;
				return e.element;
			}
		}
		return null;
	}

	// public Object find(int index){
	// if(tail==null){
	// return null;
	// }
	// while(index!=head.next.o){
	//
	// }
	// }

	public Iterator iterator() {
		return new Itr(head);
	}

	private static class Node {
		Object element;
		Node next;

		public Node(Object o, Node next) {
			super();
			this.element = o;
			this.next = next;
		}

		public Object getElement() {
			return element;
		}

	}

	private class Itr implements Iterator {

		private Node cur;

		public Itr(Node cur) {
			super();
			this.cur = cur;
		}

		public boolean hasNext() {
			return cur.next != null;
		}

		public Object next() {
			Object o = cur.next.element;
			cur = cur.next;
			return o;
		}

		public void remove() {
		}
	}
}