Class TreeNode

java.lang.Object

TreeNode

All Implemented Interfaces:

Comparable<TreeNode>

public class TreeNode
extends Object
implements Comparable<TreeNode>

Utility binary-tree (Huffman tree) node for Huffman coding. This is a simple, standard binary-tree node implementing the comparable interface based on frequency.

Version:

1.0 July 2000, 2.0 Jan 2006, 3.0 Nov 2011, 4.0 Nov 2016, 5.0 Apr 2017

Author:

Owen Astrachan, minor changes Mike Scott, version >= 3.0

Constructor Summary

Constructors

Constructor and Description
TreeNode(int value, int freq) construct leaf node (null children)
TreeNode(TreeNode leftSubtree, int value, TreeNode rightSubtree) construct internal node (with children). pre: leftSubtree != null, righSubtree != null The new node's frequency will be the sum of the frequencies of leftSubtree and rightSubtree.

Method Summary

Methods

Modifier and Type	Method and Description
int	compareTo(TreeNode rhs) Return value based on comparing this TreeNode to another.
int	getFrequency() Get the frequency of this node.
TreeNode	getLeft() Get the left child of this node.
TreeNode	getRight() Get the right child of this node.
int	getValue() Get the value stored in this node.
boolean	isLeaf() Is this node a leaf or not.
void	setLeft(TreeNode newLeft) Set the left child of this TreeNode to the given value.
void	setRight(TreeNode newRight) Set the right child of this TreeNode to the given value.
String	toString() Return a String version of this node.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

TreeNode

public TreeNode(int value,
        int freq)

construct leaf node (null children)

Parameters:

value - is the value stored in the node (e.g., value from original file)

freq - is number of times value occurred (e.g., count of # occurrences)

TreeNode

public TreeNode(TreeNode leftSubtree,
        int value,
        TreeNode rightSubtree)

construct internal node (with children).
pre: leftSubtree != null, righSubtree != null
The new node's frequency will be the sum of the frequencies of leftSubtree and rightSubtree.

Parameters:

value - the stored as value of node

leftSubtree - is left subtree

rightSubtree - is right subtree

Method Detail

compareTo

public int compareTo(TreeNode rhs)

Return value based on comparing this TreeNode to another.

Specified by:

compareTo in interface Comparable<TreeNode>

Returns:

value < 0 if this < rhs, value > 0 if this > rhs, and 0 if this == rhs

toString

public String toString()

Return a String version of this node.

Overrides:

toString in class Object

Returns:

A String version of this node including the frequency (weight) and value.

getValue

public int getValue()

Get the value stored in this node.

Returns:

the value stored in this node

getFrequency

public int getFrequency()

Get the frequency of this node.

Returns:

the frequency of this node. For internal nods the value should be the sum of the child nodes

getLeft

public TreeNode getLeft()

Get the left child of this node.

Returns:

The left child of this node. If no left child, returns null.

getRight

public TreeNode getRight()

Get the right child of this node.

Returns:

The right child of this node. If no right child, returns null.

isLeaf

public boolean isLeaf()

Is this node a leaf or not.

Returns:

true if this node is a leaf, false if it is an internal node

setLeft

public void setLeft(TreeNode newLeft)

Set the left child of this TreeNode to the given value.

Parameters:

newLeft - The new left child for this TreeNode.

setRight

public void setRight(TreeNode newRight)

Set the right child of this TreeNode to the given value.

Parameters:

newRight - The new right child for this TreeNode.