I am now making the huffman algorithm. I have generated the tree but I cannot generate the codes.. please if anyone can help tell me how?

This is the class Node

public class Node 
{
	private Node left=null;
	private Node right = null;
	private Node parent = null;
	boolean visited = false; 
	int weight;
	String data;
	String code;
	public Node() {
		
	}
	public void setLeft(Node l)
	{
		left = l;
	}
	public void setRight(Node r)
	{
		right = r;
	}
	public void setParent(Node p)
	{
		parent = p;
	}
	public void setWeight(int w)
	{
		weight = w;
	}
	public void setData(String d)
	{
		data = d;
	}
	public void setCode(String c)
	{
		code = c;
	}
	
	////////////////////////
	public Node getLeft()
	{
		return left;
	}
	public Node getRight()
	{
		return right;
	}
	public Node getParent()
	{
		return parent;
	}
	public int getWeight()
	{
		return weight;
	}
	public String getData()
	{
		return data;
	}
	public String getCode()
	{
		return code;
	}
	
	public String toString()
	{
		return getData()+"  "+getWeight()+"  ";
	}
	
}

This is the Compressor Code

import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.ArrayList;
import java.util.Stack;

public class Compressor 
{
	Compressor(RandomAccessFile source,RandomAccessFile destination) throws IOException
	{
		
		
		RandomAccessFile file = source;
		StringBuffer input=new StringBuffer();
		ArrayList<String> ch = new ArrayList<String>();
		ArrayList<Integer> ints = new ArrayList<Integer>();
		ArrayList<Node> tree = new ArrayList<Node>();
		//Reading From File
		while(file.getFilePointer()<file.length())
		{
			input.append(file.readLine());
			if(file.getFilePointer()!=file.length())
			{
				input.append("\n");
			}
		}
		System.out.println(input);
		//ArrayList of freq and chars
		for(int l=0;l<input.length();l++)
		{
			String x="";
			x+=	input.charAt(l);
			if(ch.lastIndexOf(x)==-1)
			{
				ch.add(x);
				ints.add(1);
			}
			else
			{
				ints.set(ch.lastIndexOf(x), ints.get(ch.lastIndexOf(x))+1);
				//ints.set(ch.lastIndexOf(input.charAt(l)), ints.get(ch.lastIndexOf(input.charAt(l)))+1);
			}
		}
		
		//Arraylist Of Nodes
		for (int i=0;i<ch.size();i++)
		{
			Node n1 = new Node();
			n1.setData(ch.get(i));
			n1.setWeight(ints.get(i));
			tree.add(n1);
		}
		
		//Sorting the Nodes
		simSort(tree);
		
		for (int i=0;i<tree.size();i++)
			System.out.println(tree.get(i).getData()+"   "+tree.get(i).getWeight());
		System.out.println(tree.toString().toString());
		//Building the tree
		while(tree.size()!=1)
		{
			Node parent = new Node();
			parent.setWeight(tree.get(tree.size()-1).getWeight()+tree.get(tree.size()-2).getWeight());
			parent.setRight(tree.get(tree.size()-1));
			parent.setLeft(tree.get(tree.size()-2));
			parent.setData(tree.get(tree.size()-2).getData()+tree.get(tree.size()-1).getData());
			tree.remove(tree.size()-1);
			tree.remove(tree.size()-1);
			tree.add(parent);
			tree.trimToSize();
			simSort(tree);
			System.out.println(tree.toString().toString());
		}
		
		//Traversing the Tree and Generating Codes
		Node oneTree = new Node();
		oneTree = tree.get(0);	
		traverseTree(oneTree);
	}
	
	public void simSort(ArrayList<Node> n)
	{
		for(int i=0;i<n.size()-1;i++)
		{
			for (int j=0;j<n.size()-1;j++)
			{
				if(n.get(j).getWeight()<n.get(j+1).getWeight())
				{
					Node temp = new Node();
					temp = n.get(j);
					n.set(j, n.get(j+1));
					n.set(j+1, temp);
				}
			}
		}
	}
	public void traverseTree(Node root) 
	{
		   Stack nodes = new Stack();
		   nodes.push(root);
		   Node currentNode= new Node();
		   while (! nodes.isEmpty())
		   {
		      currentNode = (Node) nodes.pop();
		      Node right = currentNode.getRight();
		      if (right != null)
		         nodes.push(right);
		      Node left = currentNode.getLeft();
		      if (left != null)
		         nodes.push(left);      
		      System.out.println("Node data: "+currentNode.data);
		   }
	}
}

When I run this code it generates the tree but I don't know how to generate the codes using the tree.

Thanks

I am now making the huffman algorithm. I have generated the tree but I cannot generate the codes.. please if anyone can help tell me how?

See this article for a quick explanation and some examples.

From the article:

Traverse the constructed binary tree from root to leaves assigning and accumulating a '0' for one branch and a '1' for the other at each node. The accumulated zeroes and ones at each leaf constitute a Huffman encoding for those symbols and weights.

how can i develop a huffman compression algorithm in java for compressing data ,try to provide some source code

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