//node.java
/*---------------------------------------------------------------
' class node for package dataStruct
'
' Shawn McKenna
'
' DESC: This class is an implementation of a single-linked list and some appropriate
' 	  methods for creating, inserting and deleting single linked nodes.  The list holds
'	  String data, though it can always be changed to hold more fields or objects. 
' 
' NOTE:   Many of these methods are taken directly from Geoff Friesen's "Java 2 by Example"
'	    a good beginning/intermediate Java book -- though the inserting and deleting methods
'	    are mine.  Since Java does not have pointers, a double linked list is much easier
'	    to implement than a single linked list.
'	    Java also has a linked list class for objects (java.util.LinkedList).  
'
' GENERIC NOTE:	All my code has been tested, my apologies for any unforseen errors.  
'			Suggestions are always welcome.  Feel free to use or change any of this 
'			code.
'
' CONSTRUCTOR: node (String data) -- public
'
' METHODS:
'	setData(String data) -- public
'     	DESC: sets the data for the current node.                
'		RETURN TYPE: void	
'	getData () -- public
'		DESC: returns the current string value for the current node.
'		RETURN TYPE: String
'	setNext (node next) -- public
'		DESC: sets the next node for the current node.
'		RETURN TYPE: void
'	getNext () -- public
'		DESC: returns the next node.
'		RETURN TYPE: node
'	insertB (node topB, String data) -- public
'		DESC: inserts a node at the beginning.
'		RETURN TYPE: node
'	insertA (node top, String data) -- public
'		DESC: inserts a node at the end of the linked list.
'		RETURN TYPE: node
'	insertA (node top, node temp) -- public
'		DESC: inserts a node or a linked list at the end of the original linked list.
'		RETURN TYPE: node
'	insertIB (node top, String data, String after) -- public
'		DESC: inserts a node inbetween nodes.  It does this by finding the String 'after'
'			and inserting the String 'data' after 'after' he he he.
'		RETURN TYPE: node
'		NOTE: if 'after' does not exist in linked list, the linked list is not changed.
'			This can be changed later to possibly add some Exception when the 'after' is
'			not found.
'	deleteNode (node top, String data) -- public
'		DESC: deletes a node where the String 'data' matches the passed parameter.
'		RETURN TYPE: node
'		NOTE: if 'data' does not exist in linked list, the linked list is not changed.
'			This can be changed later to possibly add some Exception when the 'data' is
'			not found.
'
' EXAMPLE FOR DECLARING METHODS --
'		node top = new node("rest");	
'		top = top.insertB(top, "hello");
'		top = top.insertA(top, "Last");
'		top = top.insertIB(top, "NotWork", "but"); //no but String so linked list is not 	
'		top = top.insertIB(top, "SecondLast", "rest");
'		top = top.deleteNode(top, "but"); //no but String, so linked list is not changed.
'		top = top.deleteNode(top, "Last");
'
' DATE MODIFIED:	 11/5/2000
' VERSION:		 1.0
'----------------------------------------------------------------
*/	

package dataStruct;

public class node
{
	private String data; // data for the node
	private node next;   // declare the next node

	public node (String data)
	{
		setData (data);
		setNext (null);
	} // end of constructor

	public void setData (String data)
	{
		this.data = data;
	} // end of method setData

	public String getData ()
	{
		return data;
	} // end of method getData

	public void setNext (node next)
	{
		this.next = next;
	} // end of method setNext

	public node getNext ()
	{
		return next;
	} // end of method getNext

	public node insertB (node topB, String data)
	{
		node temp = new node (data);
		temp.setNext (topB);
		topB = temp;
		
		return topB;
	} // end of method insertB

	public node insertA (node top, String data)
	{
		node temp = new node (data);
		node last = top;
		
		while (last != null)
			if (last.getNext () != null)
				last = last.getNext ();
			else
				break;
		if (last != null)
			last.setNext (temp);
		else
			top = temp;

		return top;
	} // end of method insertA

	public node insertA (node top, node temp)
	{
		node last = top;
		
		while (last != null)
			if (last.getNext () != null)
				last = last.getNext ();
			else
				break;
		if (last != null)
			last.setNext (temp);
		else
			top = temp;

		return top;
	} // end of method insertA

	public node insertIB (node top, String data, String after)
	{
		node tempIB = null; 
		node insert = null ; // the new node with data

		while (top != null) {
			if (tempIB != null) {
				tempIB = insertA(tempIB, top.getData()); 
			}
			else
				tempIB = new node(top.getData());	
			
			if (top.getData() == after) {
				insert = new node(data); // the new node with data
				node second = top.getNext(); 
				insert.setNext (second);
				break;
			} // end of if statement

			top = top.getNext ();
			
		} // end of while
		
		tempIB = insertA (tempIB, insert);
		
		return tempIB;
	} // end of method insertIB

	public node deleteNode (node top, String data)
	{
		node temp = top;
		node prev = null;

		while (temp != null)
		{
			if (temp.getData().equals (data))
			{
				if (prev != null)
					prev.setNext (temp.getNext());
				else 
					top = temp.getNext();
				break;
			} // end of if statement
			else
			{
				prev = temp;
				temp = temp.getNext();
			} // end of else statement
		} // end of while

		return top;
	} // end of method deleteNode
} // end of class node