A Basic Implementation of Generic Tree in Java

A generic tree data structure can be implemented in Java with the concept of an object to define a node and the object itself having a reference to n children nodes (or null to point the tree termination i.e. Leaf Nodes).

The following is a very trivial implementation of this data structure to show the concept of generic tree. The use of an array is completely voluntary, you can use any other datastructure of your choice to hold the children based on your need (Such as ArrayList or even LinkedLists).

This code any any other codes published in this blog are also available at Github (search for icodejava)

package com.icodejava.blog.published.datastructure;

/**
 * 
 * @author Kushal Paudyal www.icodejava.com Created On - Dec 5, 2016 Last
 *         Modified On - Dec 5, 2016
 * 
 *         This class shows a basic implementation of Generic Tree concept in
 *         Java.
 */
public abstract class AbstractGenericTreeNode {

	private AbstractGenericTreeNode [] children;

	public AbstractGenericTreeNode [] getChildren() {
		return children;
	}

	public void setChildren(AbstractGenericTreeNode [] children) {
		this.children = children;
	}
	
	public int getNumberOfChildren () {
		
		return children != null ? children.length : 0;
	}
	
}

The following is a concrete implementation of the Abstract node above and is defined to hold integer values. You however can implement this class to hold the object of your choice.

package com.icodejava.blog.published.datastructure;

/**
 * 
 * @author Kushal Paudyal www.icodejava.com Created On - Dec 5, 2016 Last
 *         Modified On - Dec 5, 2016
 * 
 *         This class shows a basic implementation of Generic Tree concept in
 *         Java.
 */

public class IntegerTreeNode extends AbstractGenericTreeNode {
	private int value;

	public IntegerTreeNode(int value, AbstractGenericTreeNode[] children) {
		super();
		this.value = value;
		this.setChildren(children);
	}

	public int getValue() {
		return value;
	}

}

Generic trees are different from Binary Trees. Binary Trees have 2 child nodes at maximum whereas the generic trees can have n-number of children.