access global variable in static method in java

Question

Is there any way to use the global variable in the static methods? My goal is to print the contents of an ArrayList containing objects (Food and nonFood). I thought a toString() method would be the best way to print it but cant seem to get it to work. I have tried to use global variables but when I use the this. keyword, it says cannot use this in static context. The methods have to be static because I don't want to have to instantiate the class. Any suggestions?

In the printInven() method I've also tried to do System.out.println(i+1 + " " + inven.get(i).toString()); I am completely available to use a different method of printing the objects in the ArrayList. I thought getting the global variables work would be the best way to use the toString() method.

import java.util.ArrayList;
import java.util.Scanner;

public class Inventory{
    public static ArrayList<Items> inven = new ArrayList<Items>();
    Scanner scan = new Scanner (System.in);
    private String name;
    private static int ID;
    private double price;
    private boolean in_stock;
    private boolean food;
    public static void main(String[] args) {
    
    }

    //Add Food Item
    public static void addFood(String name, int ID, double price, boolean in_stock, boolean food){
        name = name;
        ID = ID;
        price = price;
        in_stock = in_stock;
        food = food;

        Food newFood = new Food(name, ID, price, in_stock, food);
        inven.add(newFood);
    }

    //Add Non food item
    public static void addNonFood(String name, int ID, double price, boolean in_stock, boolean food){
        name = name;
        ID = ID;
        price = price;
        in_stock = in_stock;
        food = food;

        NonFood newNonFood = new NonFood(name, ID, price, in_stock, food);
        inven.add(newNonFood);
    }

    //Delete inventory
    public static void delInven(int num){
        inven.remove(num);
    }

     //Print Inventory
    public static void printInven(){
        for(int i = 0; i < inven.size(); i++){
            System.out.println(i+1 + " " + inven.get(i));
        }
    }
    

    //Clear Inventory
    public static void clearInven(){
        inven.clear();
    }

    //Replace item
    //Polymorphism for food and non food items
    public static void replaceNewNonFoodInven(int n, String name, int ID, double price, boolean in_stock, boolean food){
        name = name;
        ID = ID;
        price = price;
        in_stock = in_stock;
        food = food;
        NonFood newNonFood = new NonFood(name, ID, price, in_stock, food);
        inven.set(n, newNonFood);
    }    
}

Your question is unclear. You want to do something you already do and explain an issue for an approach which isn't relevant/used anymore. What is your current issue? — Tom, Mar 24 '21 at 03:12
You have a lot of pointless "x = x" assignments in your code, which makes me think you don't have a good grasp on either the scope of names, or the distinction between instance variables and class variables. — user15187356, Mar 24 '21 at 03:15
It would be a lot easier if you would just create an instantiated Inventory and forget about using static for this. — NomadMaker, Mar 24 '21 at 03:49
I am trying to print the objects in the ArrayList. When I print it right now, it outputs `project.Food@7cc355be` Yes, I do not have a good grasp of java quite yet. I'm in high school and just started learning Java. If I instantiate the Inventory class, would I be able to instantiate the Food and NonFood classes as well? Any suggestions would be very much appreciated! — zooboo, Mar 24 '21 at 04:38
Does this answer your question? [How do I print my Java object without getting "SomeType@2f92e0f4"?](https://stackoverflow.com/questions/29140402/how-do-i-print-my-java-object-without-getting-sometype2f92e0f4) — Tom, Mar 24 '21 at 10:21

score 0 · Accepted Answer · answered Mar 24 '21 at 05:53

You can refer below code. I hope this will resolve you queries.

public class NonFood {

private String name;
private static int ID;
private double price;
private boolean in_stock;
private boolean food;

public NonFood(String name, int iD, double price, boolean in_stock, boolean food) {
    this.name = name;
    this.ID = iD;
    this.price = price;
    this.in_stock = in_stock;
    this.food = food;
}

@Override
public String toString() {
    return "Name: '" + this.name + "' ID: '" + this.ID + "' price: '" + this.price + "' in_stock: '" + this.in_stock + "' food: '" + this.food +"'";
}

}

public class Food {

private String name;
    private static int ID;
    private double price;
    private boolean in_stock;
    private boolean food;

public Food(String name, int iD, double price, boolean in_stock, boolean food) {
    this.name=name;
    this.ID=iD;
    this.price=price;
    this.in_stock=in_stock;
    this.food=food;
}

@Override
public String toString() {
    return "Name: '" + this.name + "' ID: '" + this.ID + "' price: '" + this.price + "' in_stock: '" + this.in_stock + "' food: '" + this.food +"'";
}

}

public class Inventory{

public static ArrayList<Object> inven = new ArrayList<Object>();
Scanner scan = new Scanner (System.in);

private String name;
private static int ID;
private double price;
private boolean in_stock;
private boolean food;

public static void main(String[] args) {

    for (int i = 0; i < 2; i++) {
        addFood("Food"+i, i, 100+i, true, true);
    }
    
    for (int i = 0; i < 2; i++) {
        addNonFood("NonFood"+i, i, 100+i, true, true);
    }
    
    printInven();
}

//Add Food Item
public static void addFood(String name, int ID, double price, boolean in_stock, boolean food){
  Food newFood = new Food(name, ID, price, in_stock, food);
    inven.add(newFood);
}

//Add Non food item
public static void addNonFood(String name, int ID, double price, boolean in_stock, boolean food){
    NonFood newNonFood = new NonFood(name, ID, price, in_stock, food);
    inven.add(newNonFood);
}

//Delete inventory
public static void delInven(int num){
    inven.remove(num);
}

 //Print Inventory
public static void printInven(){
    for(int i = 0; i < inven.size(); i++){
        System.out.println(i+1 + " " + inven.get(i));
    }
}


//Clear Inventory
public static void clearInven(){
    inven.clear();
}

//Replace item
//Polymorphism for food and non food items
public static void replaceNewNonFoodInven(int n, String name, int ID, double price, boolean in_stock, boolean food){
    NonFood newNonFood = new NonFood(name, ID, price, in_stock, food);
    inven.set(n, newNonFood);
}

}

access global variable in static method in java

1 Answers1