How to implement a tree data-structure in Java?

Question

Is there any standard Java library class to represent a tree in Java?

Specifically I need to represent the following:

• The sub-tree at any node can have

Answer 1

There is no specific data structure in Java which suits to your requirements. Your requirements are quite specific and for that you need to design your own data structure. Looking at your requirements anyone can say that you need some kind of n-ary tree with some specific functionality. You can design your data structure in following way:

1. Structure of the node of the tree would be like content in the node and list of children like: class Node { String value; List children;}
2. You need to retrieve the children of a given string, so you can have 2 methods 1: Node searchNode(String str), will return the node that has the same value as given input (use BFS for searching) 2: List getChildren(String str): this method will internally call the searchNode to get the node having same string and then it will create the list of all string values of children and return.
3. You will also be required to insert a string in tree. You will have to write one method say void insert(String parent, String value): this will again search the node having value equal to parent and then you can create a Node with given value and add to the list of children to the found parent.

I would suggest, you write structure of the node in one class like Class Node { String value; List children;} and all other methods like search, insert and getChildren in another NodeUtils class so that you can also pass the root of tree to perform operation on specific tree like: class NodeUtils{ public static Node search(Node root, String value){// perform BFS and return Node}