Btree implementation

[craggy reef]

Hello I am struggling with the implementing part of my assignment that requires me to Create Functions for the BtreeNode class and Btree class and I am unsure of how my implementation of the insert is supposed to work.

public class BTreeNode<T extends Comparable<T>> {
    public Comparable<T>[] nodeData;
    public BTreeNode<T>[] nodeChildren;
    public BTreeNode<T> parent;
    public int size;

    @SuppressWarnings("unchecked")
    public BTreeNode(int size) {
        this.size = size;
        nodeData = new Comparable[size];
        nodeChildren = new BTreeNode[size + 1];
        //nodeData and NodeChildren are set to 1 more than the size of the node to allow for overflow
        this.parent = null;
    }

    public Comparable<T> getIndex(int i) {

        if (i < 0 || i >= size) {
            return null;
        }
        return nodeData[i];
    }

    public BTreeNode<T> ascend() {
        return parent;
    }

    public BTreeNode<T> descend(int i) {
        //return nodeChildren[i];
        if (i < 0 || i >= size + 1) {
            return null;
        }
        return nodeChildren[i];

    }

    /* -------------------------------------------------------------------------- */
    /* Helpers */
    /* -------------------------------------------------------------------------- */

    public String toString() {
        String out = "|";
        for (int i = 0; i < nodeData.length; i++) {
            if (nodeData[i] == null) {
                out += "null|";
            } else {
                out += nodeData[i].toString() + "|";
            }

        }
        return out;
    }

}

above is my current implementation of the BTreeNode class

[crisp summit]

Detected code, here are some useful tools:

Formatted code

public class BTreeNode<T extends Comparable<T>> {
  public Comparable<T> [] nodeData;
  public BTreeNode<T> [] nodeChildren;
  public BTreeNode<T> parent;
  public int size;
  @SuppressWarnings("unchecked") public BTreeNode(int size) {
    this .size = size;
    nodeData = new Comparable[size] ;
    nodeChildren = new BTreeNode[size + 1] ;
    //nodeData and NodeChildren are set to 1 more than the size of the node to allow for overflow
    this .parent = null ;
  }
  public Comparable<T> getIndex(int i) {
    if (i < 0 || i >= size) {
      return null ;
    }
    return nodeData[i] ;
  }
  public BTreeNode<T> ascend() {
    return parent;
  }
  public BTreeNode<T> descend(int i) {
    //return nodeChildren[i];
    if (i < 0 || i >= size + 1) {
      return null ;
    }
    return nodeChildren[i] ;
  }
  /* -------------------------------------------------------------------------- */
   /* Helpers */
   /* -------------------------------------------------------------------------- */
  public String toString() {
    String out = "|";
    for (int i = 0; i < nodeData.length; i++) {
      if (nodeData[i]  == null ) {
        out += "null|";
      }
      else {
        out += nodeData[i] .toString() + "|";
      }
    }
    return out;
  }
}

<@&987246399047479336> please have a look, thanks.

[crisp summit]

I uploaded your attachments as Gist.

[craggy reef]

i attached my BTree.java as it is to big to copy

[crisp summit]

I uploaded your attachments as Gist.

[valid yacht]

what are you confused on exactly?

we can discuss in detail but I need more details on why you think it's incorrect/vague. And what you have tried which went wrong.

[void belfry]

So the instructor created that toString method as a testing aid but yet there are no unit tests at all, including the toString method?

[crisp summit]

@craggy reef

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[craggy reef]

the instrucotr gave the tostring so that when we do our own testing, we can see if our input matches the ouptut of the btree visualiser https://www.cs.usfca.edu/~galles/visualization/BTree.html

[craggy reef]

so with the insert, I am struggling ou=n how to keep track of the leafs and when the leaf is full, how do I "lift" and make sure to adjust the leaf and split it without losing the other leafs

[void belfry]

Your instructor has given a specification which you should create the stubs for even if you don't have the guts of the methods yet. Personally, when implementing any kind of ADT, I think its important to have unit tests. That's best done with a build system like gradle. Has your instructor

said anything about tests?

or using maven or gradle?