One type of item in list

Question

I am trying to check if types of item is full or not in list.

private LinkedList<Item> items = new LinkedList<>();
items.add(new Item("Movie1", "2020", "2"));//2 right there's the amount
items.add(new Item("Movie2", "2012", "3"));
items.add(new Item("Movie3", "2011", "3"));
items.add(new Item("Movie4", "2013", "3"));

I make a limit of 3. So, if the amount is 3, then it's full.

when I say three is the amount in Movie2,2020, 3 . I mean that three. Sry for misunderstanding.

I only know how to check if a one of the item is full. But there are multiple are full.

I am struggle to check them.

Can anyone help?

Thanks.

Answer 1

Define a method as follows to add elements to the list:

static void add(LinkedList<Item> items, Item item) {
    boolean full = false;
    for (Item e : items) {
        if (e.equals(item) && e.getId().equals(String.valueOf(LIMIT)) && Integer.valueOf(item.getId()) >= LIMIT) {
            full = true;
        }
    }
    if (full) {
        System.out.println("There is no room for " + item + " in the list");
    } else {
        items.add(item);
    }
}

Demo:

import java.util.LinkedList;
import java.util.Objects;

class Item {
    String name, year, id;

    public Item(String name, String year, String id) {
        this.name = name;
        this.year = year;
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public String getYear() {
        return year;
    }

    public String getId() {
        return id;
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, year);
    }

    @Override
    public boolean equals(Object obj) {
        Item other = (Item) obj;
        return this.name.equals(other.name) && this.year.equals(other.year);
    }

    @Override
    public String toString() {
        return "[Name: " + name + ", Year: " + year + ", ID: " + id + "]";
    }
}

public class Main {
    final static int LIMIT = 3;

    public static void main(String[] args) {
        LinkedList<Item> items = new LinkedList<Item>();
        add(items, new Item("Movie1", "2010", "1"));
        add(items, new Item("Movie1", "2010", "2"));
        add(items, new Item("Movie1", "2010", "3"));
        add(items, new Item("Movie1", "2010", "3"));
        add(items, new Item("Movie1", "2010", "4"));
        add(items, new Item("Movie2", "2020", "2"));

        items.stream().forEach(System.out::println);
    }

    static void add(LinkedList<Item> items, Item item) {
        boolean full = false;
        for (Item e : items) {
            if (e.equals(item) && e.getId().equals(String.valueOf(LIMIT)) && Integer.valueOf(item.getId()) >= LIMIT) {
                full = true;
            }
        }
        if (full) {
            System.out.println("There is no room for " + item + " in the list");
        } else {
            items.add(item);
        }
    }
}

Output:

There is no room for [Name: Movie1, Year: 2010, ID: 3] in the list
There is no room for [Name: Movie1, Year: 2010, ID: 4] in the list
[Name: Movie1, Year: 2010, ID: 1]
[Name: Movie1, Year: 2010, ID: 2]
[Name: Movie1, Year: 2010, ID: 3]
[Name: Movie2, Year: 2020, ID: 2]

Note: This solution is based on the requirement that the id field is not computed as part of equals() ie two items are equal if their name and year are equal.

@Override
public int hashCode() {
    return Objects.hash(name, year);
}

@Override
public boolean equals(Object obj) {
    Item other = (Item) obj;
    return this.name.equals(other.name) && this.year.equals(other.year);
}