The ArrayList Notebook

You created a nice Note class, but now you need a class to store different Notes. In this node, we'll create a simple Class called Notebook which will contain methods for adding, retrieving and listing notes. What structure should be used in Notebook to keep track of its Notes? We've learned about Arrays, so we'll start with a simple Class that uses an array to store Notes:

public class ArrayNotebook
{
    private Note[] notes;

    /** Constructor for objects of class Notebook */
    public ArrayNotebook()
    {
        notes = new Note[10];
    }
}

This code declares an array variable for holding Note objects. The constructor initializes an empty Note array with 10 cells.

Limitations of Array
You're now ready to create a method to add Notes to notes, but you right away face the limitation of the simple array - there's no easy way to just add items to an array. You would need to create an index variable just to keep track of where to add the Notes. And what happens when you need to add more than 10 notes when the array is only 10 cells large? Things would get very messy.

public class ArrayNotebook
{
    private Note[] notes;
    private int index;
    
    public ArrayNotebook()
    {
        notes = new Note[10];
        index = 0;
    }
    
    public void addNote(Note note){
        if(index < notes.length){
            notes[index] = note;
            index++; 
        }
    }
}