The objective of this assignment is to create an undo/redo editor (that has no U

The objective of this assignment is to create an undo/redo editor (that has no UI, text document based). This is the second phase of the project.
This is a Computer Science II – Java level assignment.
The topics that pertain to this assignment are ArrayList, ArrayListStack, LinkedList, List, Queue, Enums, and Stack.
This is a fill in the blank type of assignment. The professor has given an outline and there are pre-defined classes that you must implement, specifically in this case MyArrayList(An ArrayList class) and MyArrayListStack. In the code there is green text with TODOs that specify what must be done, and each method has a comment that explains what the specified method should do.
In total there are only 10 methods that require implementation and one of them has already been filled out by the professor in the semi-completed file(specifically the open method).
For example some of the methods that need to be implemented are: save, saveAs, undo, redo, insert, delete, replace, find, moveCursor, getCursor,
These will be the attachments:
(These will be in a zip file)
1. A pre-written Editor.java file given by the professor
2. A test case file along with test text documents (however the professor has said these are untested)
3. A file that includes all the completed classes that were implemented in the first phase for context
Here are the professor’s words about how the assignment will be graded:
“My plan is to open an existing file, apply the various edits, including undo redo and save the file. I will compare it with my expected changes to see if the program works correctly.”
You are more than welcome to email me if any of the attached assignments/instructions need further explanation.