Untitled

package inventorySystem;

import java.util.Scanner;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;


public class inventory {

	public static Scanner userInput = new Scanner(System.in);
		
	public static void main(String[] args) throws IOException{
				
		while (true) {	
			inputHandler();	
		}			
	}
	
	public static void inputHandler() throws IOException {
				
			int userChoice = mainMenu();
			
			switch (userChoice) {
			case 1:
				clearScreen(100);
				addItem();
				break;
			case 2:
				clearScreen(100);
				removeItem();
				break;
			case 3:
				clearScreen(100);
				viewItem();
				break;
			case 0:
				clearScreen(100);
				exitProgram();
				break;
			default:
				clearScreen(500);
				System.out.println("That is not a valid selection, please choose another option and press enter ");
				System.out.println("PRESS ANY KEY TO CONTINUE");
				System.in.read();
				clearScreen(500);
				break;
			}			
		}		
	
	
	public static int mainMenu() {
		
		//this is the main menu to the inventory system
		System.out.println("Please choose from the following option and press enter: ");
		
		System.out.println("1. Add item to inventory");
		System.out.println("2. Remove item from inventory");
		System.out.println("3. View item in inventory");
		System.out.println("0. EXIT PROGRAM");
		
		while (!userInput.hasNextInt() ) { //input validation
			System.out.println("invlaid input, please input an integer.");
			userInput.next(); // clear invalid input 
			clearScreen(500);
		}
		
		int choice = userInput.nextInt();
		userInput.nextLine(); // consume the newline character
		
		return choice;
	}
	
	
	public static void addItem() throws IOException{
			
		System.out.println("please tell me the name of the file you would like to append data to: ");
		String fileName = userInput.nextLine();
		
		System.out.println("please input the data you wish to add: ");
		String addData = userInput.nextLine();
		
		addData = addData + "\n";
		
		try (FileWriter writer = new FileWriter(fileName, true)){
			writer.write(addData);
			System.out.println("data has been written to the file~!");
		} catch (IOException e) {
			System.out.println("oops, something went wrong: " +e.getMessage());
		}
		System.out.println("");
		System.out.println("PRESS ANY KEY TO CONTINUE");
		System.in.read();
		clearScreen(500);
	}
	
	public static void removeItem() throws IOException{
		
		System.out.println("please tell me the name of the file you wish to remove: ");
		String fileName = userInput.nextLine();
		
		try {
			if (Files.deleteIfExists(Paths.get(fileName))) {
				System.out.println("The file " + fileName + " has been deleted.");
			} else {
				System.out.println("The file " + fileName + " can not be found");
			}		
		} catch (IOException e) {
			System.out.println("Error deleting the file: " + e.getLocalizedMessage());
		}
		
		System.out.println("");
		System.out.println("PRESS ANY KEY TO CONTINUE");
		System.in.read();
		clearScreen(500);
	}
	
	public static void viewItem() throws IOException{
		
		System.out.println("please tell me the name of the file you would like to view: ");
		String fileName = userInput.nextLine();
		
		System.out.println("The following is the contents of " + fileName + ": ");
		System.out.println("");
		
		try (BufferedReader reader = new BufferedReader(new FileReader(fileName))){
			String line;
			while ((line = reader.readLine()) != null) {
				System.out.println(line);
			}
		} catch (IOException e) {
			System.out.println("Error reading the file: " + e.getMessage());
		}
		
		System.out.println(" ");
		System.out.println("PRESS ANY KEY TO CONTINUE");
		System.in.read();
		clearScreen(500);
	}
	
	public static void exitProgram() {
		
		System.out.print("ARE YOU SURE YOU WANT TO EXIT?[Y/N]: ");
		String choice = userInput.nextLine();
		
		if (choice.equalsIgnoreCase("y")) { 
			clearScreen(500);
			System.exit(0);}
		else {clearScreen(500);}
	}
		
	public static void clearScreen(int numberLines) {
		
		for (int i = 0; i <= numberLines; i++) {
			
			System.out.println("");			
		}	
	}	
}