Object oriented development with Java

The developed system should be menu driven with options for the functionalities listed in section 2.0. Menu should be repeated until the user opts to exit the system. You as an Object-oriented programming student need to identify the relationship among the entities and also develop the necessary methods needed to fulfil the requirements of the expected systems. Login access: You program should have three types of access rights such as Sales Manager, Purchase Manager and Administrator. Sales Manager should have access to the following functionalities: • Item Entry (Add/Save/Delete/Edit) • Supplier Entry (Add/Save/Delete/Edit) • Daily Item-wise Sales Entry (Add/Save/Delete/Edit) • Create a Purchase Requisition (Add/Save/Delete/Edit) • Display Requisition (View) • List of Purchaser Orders(View) Purchase Manager (PM) and should be allowed to view and access the following functionalities only: • List of Items (View) • List of Suppliers (View) • Display Requisition (View) • Generate Purchase Order (Add/Save/Delete/Edit) • List of Purchaser Orders (View) Administrator should have the rights to access and update all the application functionalities and data. They are the authorized personnel to create the above mentioned three types of users involved in the POM system. User Registration: Your program should allow the Administrators to create and register the details of users involved in the system. Validations are necessary and the system should maintain the uniqueness by having individual identification number for every user. Users should be of type SM or PM or Admin. User details need to be captured in a text file. Item Entry: Your program should allow the authorized users to enter the item details like item code, item name and the supplier id who supplies the item to TSB. Identify the various attributes needed for describing the item entity. No duplication of items allowed. Added items should be saved in a text file. All the items should be supplied by the registered suppliers of your POM system. Supplier Entry: Your program should allow the authorized users to enter the supplier details like supplier code, supplier name and the item id supplied by the supplier. Identify the various attributes needed for describing the supplier entity. No duplication of supplier allowed. Added suppliers should be saved in a text file. Daily Item-wise Sales Entry This option allows the users with access to enter the total sales of every item daily. This sale need be updated to the stock of the item accordingly. Create a PR: Your program should allow the users with access to place a purchase requisition (PR). PR should be generated for the items to be purchased to the TSB from the respective suppliers. PR typically contains the item code, quantity and the date by when it is required. It also should fetch the respective supplier code of the item. A unique identifier is required to track the PR and also the SM, who raised the PR need to be captured and saved in text file. Display a PR: Your program should allow the authorized users to view all the PRs raised by all sales managers. Generate PO Purchase Orders (PO) need to be generated only by Purchase Managers (PM). They are the only authorized users who can raise the PO. POs are basically approved Purchase Requisition raised by the Sales Managers (SM). A unique identifier is required to track the PO and also the PM, who raised the PO need to be captured and saved in text files List of Purchase Orders: Your program should allow the users with access to view the report of purchase orders raised by the Purchase Mangers (PM).