老翟

interfacepackage List;

public interface IList {
	boolean isEmpty();
	int size();
	void add(ZNode newNode);
	void insert(int index , ZNode newNode) throws Exception;
	void delete(int index) throws Exception ;
	void replace(int index,Object obj) throws Exception;
	ZNode getByIndx(int index) throws Exception;
	int getIndex(ZNode node) throws Exception;
	void display() throws Exception;
}

implementpackage List;

public class ZList implements IList {

	private ZNode head = null;
	
	public ZList(){
		
	}
	
	@SuppressWarnings("null")
	@Override
	public void add(ZNode newNode) {
		// TODO Auto-generated method stub
		ZNode z = head ;
		if(!isEmpty()){
			while(z.getNext()!=null){
				z = z.getNext();
			}
			z.setNext(newNode);
		}else{
			head = newNode ;
		}
		
	}

	@Override
	public void insert(int index, ZNode newNode) throws Exception {
		// TODO Auto-generated method stub
		ZNode frontNode = getByIndx(index-1) ;
		ZNode afterNode = getByIndx(index);
		frontNode.setNext(newNode);
		newNode.setNext(afterNode);
		
	}

	@Override
	public void delete(int index) throws Exception {
		// TODO Auto-generated method stub
		ZNode frontNode = getByIndx(index-1) ;
		ZNode currentNode = getByIndx(index) ;
		ZNode afterNode = currentNode.getNext() ;
		
		frontNode.setNext(afterNode) ;
		currentNode = null ;
		
	}

	@Override
	public void replace(int index,Object obj) throws Exception {
		// TODO Auto-generated method stub
		ZNode current = getByIndx(index);
		current.setData(obj);
	}

	/**
	 * index >= 0
	 */
	@Override
	public ZNode getByIndx(int index) throws Exception {
		// TODO Auto-generated method stub
		if(isEmpty()) throw new Exception("The List is null!");
		ZNode z = head ;
		while(index>0 ){
			if(z==null) throw new Exception("the index is out of index");
			z = z.getNext();
			index--;
		}
		
		return z;
	}

	@Override
	public int getIndex(ZNode node) throws Exception {
		// TODO Auto-generated method stub
		if(isEmpty()) throw new Exception("The List is null!");
		ZNode z = head ;
		
		int index = 0 ;
		
		do{
			if(z.equals(node)) break; 
			index ++ ;
			z = z.getNext();
		}while(z!=null);
		
		return index;
	}

	@Override
	public boolean isEmpty() {
		// TODO Auto-generated method stub
		return (null == this.head) ? true:false;
	}

	@Override
	public int size() {
		// TODO Auto-generated method stub
		ZNode z = head;
		int sz = 0;
		if(null != z) {
			do{
				sz++;
			}while((z = z.getNext())!=null);
		}
		return sz;
	}

	@Override
	public void display() throws Exception {
		// TODO Auto-generated method stub
		if(isEmpty()) throw new Exception("The List is null!");
		
		ZNode z = head ;
		int index = 0 ;
		do{
			System.out
					.println("index:" + index + " " + z.getData().toString());
			index++ ;
			z = z.getNext() ;
		}while(z!= null) ;
	}
	
}

nodepackage List;

public class ZNode {
	private Object data ;
	private ZNode next ;
	
	public ZNode(Object data, ZNode next) {
		super();
		this.data = data;
		this.next = next;
	}
	public ZNode() {
		this.data = null ;
		this.next = null ;
	}
	public Object getData() {
		return data;
	}
	public void setData(Object data) {
		this.data = data;
	}
	public ZNode getNext() {
		return next;
	}
	public void setNext(ZNode next) {
		this.next = next;
	}
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((data == null) ? 0 : data.hashCode());
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		ZNode other = (ZNode) obj;
		if (data == null) {
			if (other.data != null)
				return false;
		} else if (!data.equals(other.data))
			return false;
		return true;
	}
	@Override
	public String toString() {
		// TODO Auto-generated method stub
		return "data are : " + data.toString() ;
	}
	
}