package com.itjob.data;

public class SingleLink {
	public Node head;
	public Node rear;
	public Node parrent;
	
	public void add(Object data){
		if (head == null){
			head = new Node(data);
			rear = head;
		}else{
			rear.next = new Node(data);
			rear = rear.next;
		}
	}
	
	public boolean delete(Object data){
		Node result = find(data);
		if (result == null){
			return false;
		}else{
			if (result == head){
				head = head.next;
				if (head == null){
					rear = null;
				}
			}else{
				parrent.next = result.next;
				if (parrent.next == null){
					rear = parrent;
				}
			}
			return true;
		}
		
	}
	
	public boolean update(Object oldData,Object newData){
		Node temp = find(oldData);
		if (temp == null){
			return false;
		}else{
			temp.data = newData;
			return true;
		}
	}
	
	public Node find(Object data){
		
		Node temp = head;
		parrent = head;
		
		while (temp != null){
			if (temp.data.equals(data)){
				return temp;
			}
			parrent = temp;
			temp = temp.next;
		}
		return null;
	}
	
	public String toString(){
		StringBuilder result = new StringBuilder("[");
		Node temp = head;
		while (temp != null){
			if (temp == rear){
				result.append(temp.data);
			}else{
				result.append(temp.data + ",");
			}
			temp = temp.next;
		}
		result.append("]");
		return result.toString();
	}
}