// Class Tree that defines a tree of objects
// Version of 2/11/98

import java.lang.*;
import java.util.*;


public class Tree extends Object implements Cloneable
{

	public Object NodeContent;
	private Vector ChildrenNodes;

	public Tree()
	{
		super();
		NodeContent = new Object();
		ChildrenNodes = new Vector();
	}

	public Tree(Object TheObject)
	{
		super();
		NodeContent = TheObject;
		ChildrenNodes = new Vector();
	}

	public synchronized Tree Clone()
	{
		Tree TheNewTree;
		if (NodeContent != null)
		{
			TheNewTree = new Tree(NodeContent);
			if (!(IsLeaf()))
			{
				for (int i = 0; i < BranchNumber(); i++)
				{
					TheNewTree.AddChildren(GetChild(i).Clone());
				}
			}
		}
		else
		{
			TheNewTree = new Tree();
		}
		return TheNewTree;
	}

	public final synchronized boolean IsLeaf() throws NullPointerException
	{
		boolean TheQuestion = true;
		if (NodeContent == null)
		{
			System.out.println("Can't know if IsLeaf() for an empty tree.");
			throw new NullPointerException();
		}
		else
		{
			TheQuestion = ChildrenNodes.isEmpty();
		}
		return TheQuestion;
	}

	public final synchronized boolean IsEmpty()
	{
		return (NodeContent == null);
	}

	public final synchronized void AddChildren(Tree TheTree) throws NullPointerException
	{
		if (NodeContent == null)
		{
			System.out.println("Can't AddChildren(Atree) for an empty tree.");
			throw new NullPointerException();
		}
		else
		{
			ChildrenNodes.addElement(TheTree);
		}
	}

	public final synchronized int BranchNumber() throws NullPointerException
	{
		int TheNumber = 0;
		if (NodeContent == null)
		{
			System.out.println("No Branch for an empty tree.");
			throw new NullPointerException();
		}
		else
		{
			TheNumber = ChildrenNodes.size();
		}
		return TheNumber;
	}

	public final synchronized boolean Fruitful() throws NullPointerException
	{
		boolean TheFruitAlive = true;
		if (NodeContent == null)
		{
			System.out.println("Can't Fruitful() for an empty tree.");
			throw new NullPointerException();
		}
		else
		{
			if (!(IsLeaf()))
			{
				int i = 0;
				while ((i < BranchNumber()) && TheFruitAlive)
				{
					TheFruitAlive = (TheFruitAlive && GetChild(i).GivesFruit(NodeContent.getClass()));
					i++;
				}
			}
		}
		return TheFruitAlive;
	}

	private final synchronized boolean GivesFruit(Class TheClass) throws NullPointerException
	{
		boolean TheFruitGiven = true;
		if (NodeContent == null)
		{
			System.out.println("Can't verify GivesFruit(AClass) for an empty tree.");
			throw new NullPointerException();
		}
		else
		{
			if (IsLeaf())
			{
				TheFruitGiven = (TheClass == NodeContent.getClass());
			}
			else
			{
				int i = 0;
				while ((i < BranchNumber()) && TheFruitGiven)
				{
					TheFruitGiven = (TheFruitGiven && GetChild(i).GivesFruit(NodeContent.getClass()));
					i++;
				}
			}
		}
		return TheFruitGiven ;
	}

	public final synchronized void insertChildrenAt(Tree TheTree, int index) throws	NullPointerException,
															NoSuchElementException
	{
		if (NodeContent == null)
		{
			System.out.println("Can't insertChildrenAt(Atree,AIndex) for an empty tree.");
			throw new NullPointerException();
		}
		else
		{
			try
			{
				ChildrenNodes.insertElementAt(TheTree, index);
			}
			catch (ArrayIndexOutOfBoundsException TheException)
			{
				System.out.println("Invalid child index for this tree: " + TheException);
				throw new NoSuchElementException();
			}
		}
	}

	public final synchronized Tree GetChild(int index) throws ArrayIndexOutOfBoundsException
	{
		Tree TheChildTree = new Tree();
		try
		{
			TheChildTree = (Tree) ChildrenNodes.elementAt(index);
		}
		catch (ArrayIndexOutOfBoundsException TheException)
		{
			System.out.println("Invalid child index for this tree: " + TheException);
			throw new ArrayIndexOutOfBoundsException();
		}
		return TheChildTree;
	}

	public final synchronized Tree GetFirstChild() throws NoSuchElementException
	{
		Tree TheChildTree = new Tree();
		try
		{
			TheChildTree = (Tree) ChildrenNodes.firstElement();
		}
		catch (NoSuchElementException TheException)
		{
			System.out.println("No child for this tree: " + TheException);
			throw new NoSuchElementException();
		}
		return TheChildTree;
	}

	public final synchronized Tree GetLastChild() throws NoSuchElementException
	{
		Tree TheChildTree = new Tree();
		try
		{
			TheChildTree = (Tree) ChildrenNodes.lastElement();
		}
		catch (NoSuchElementException TheException)
		{
			System.out.println("No child for this tree: " + TheException);
			throw new NoSuchElementException();
		}
		return TheChildTree;
	}

	public final synchronized String toString()
	{
		String TheString = new String();
		if (NodeContent != null)
		{
			TheString = TheString.concat(NodeContent.toString());
			if (!(IsLeaf()))
			{
				TheString = TheString.concat(" (");
				for (int i = 0; i < (BranchNumber() - 1); i++)
				{
					TheString = TheString.concat(GetChild(i).toString() + ", ");
				}
				TheString = TheString.concat(GetChild(BranchNumber() - 1).toString());
				TheString = TheString.concat(")");
			}
		}
		return TheString;
	}

}