/*
 *****************************************************************************
 *		File Name: LeafNode.java
 *		Purpose: class representing a leaf in b+-tree
 *		Authors: Han Don, Jeff Xing, Carol Cheung
 *		Version: 1
 *		Last Date Updated: Feb. 27, 2001
 ****************************************************************************/

/**
 *  LeafNode holds a piece of string in a character
 *  array, and a pointer to its younger sibling.
 *  It provides the services that the the BTreeString requires.  
 */
public class LeafNode {

	/**
	 *  The maximum length of string that I can hold.
	 */
	public final static int SMALL_STRING_LENGTH = 4096;
	
	/**
	 *  Pointer to my younger sibling.
	 */
	private LeafNode nextNode;
	
	/**
	 *  The char array in which I holds a piece of string.
	 */
	private char [] elements;	
	
	/**
	 *  My key.
	 */
	private long key; 
	
	
	/**
	 *  Construct a new leaf.
	 *  precondition: value.length <= SMALL_STRING_LENGTH.
	 */
	public LeafNode(char [] value, long k) {
		elements = value;
		nextNode = null;
		key = k;
	}
	
	/**
	 *  Return my younger sibling.
	 */
	public LeafNode getNext() { return nextNode; }
	
	/**
	 *  Link me and my younger sibling.
	 */
	public void setNext(LeafNode theNext){ 
		nextNode = theNext;
	}
	
	/**
	 *  Return the character of the char array at index i.
	 *  Precondition: 0<= i < SMALL_STRING_LENGTH
	 */
	public char getElementAt(int i) { 
		return elements[i]; }

	/**
	 *  Return a new string representing the value of elements.
	 */
	public String toString() { 
		return (new String(elements)); }
	
	/**
	 *  Return a new string representing the value of elements 
	 *  between the 'begin' and 'end' indice.
	 *  precondition: 0 <= begin <= end <= elements.length
	 */
	public String stringBetween(int begin, int end) {
		if(begin == end) return "";
		else
			return (new String(elements, begin, end - begin));
	}
		
}