Main ----->

package E3_ShoppingSpree;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        Map<String, Person> collectPeople = new LinkedHashMap<>();
        Map<String, Product> productsCollect = new LinkedHashMap<>();


        try {
            String[] people = reader.readLine().split(";");
            for (String person : people) {

                String[] tokens = person.split("=");
                Person person1 = new Person(tokens[0], Double.parseDouble(tokens[1]));
                collectPeople.putIfAbsent(tokens[0], person1);
            }

            String[] products = reader.readLine().split(";");

            for (String product : products) {
                String[] tokens = product.split("=");
                Product product1 = new Product(tokens[0], Double.parseDouble(tokens[1]));
                productsCollect.putIfAbsent(tokens[0], product1);
            }

            String line;
            while (!"end".equalsIgnoreCase(line = reader.readLine())) {
                String[] tokens = line.split("\\s+");
                String name = tokens[0];
                String productName = tokens[1];
                if (collectPeople.containsKey(name) && productsCollect.containsKey(productName)) {
                    Person person = collectPeople.get(name);
                    Product product = productsCollect.get(productName);
                    person.buyProduct(product);
                }
            }


        } catch (IllegalArgumentException e) {
            System.out.println(e.getMessage());
        }
        collectPeople.values().forEach(System.out::println);
    }
}



Person ----------->

package E3_ShoppingSpree;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

public class Person implements ValidateData {
    private String name;
    private double money;
    private List<Product> products;

    public Person(String name, double money) {
        this.setName(name);
        this.setMoney(money);
        this.products = new ArrayList<>();
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        validateName(name);
        this.name = name;
    }


    public double getMoney() {
        return this.money;
    }

    public void setMoney(double money) {
        validateNumber(money);
        this.money = money;
    }

    public void buyProduct(Product product) {
        if (product == null) {
            throw new IllegalArgumentException();
        }
        if (this.getMoney() - product.getCost() < 0) {
           throw  new IllegalArgumentException(String.format("%s can't afford %s", this.name, product.getName()));
        } else {
            this.products.add(product);
            this.setMoney(this.getMoney() - product.getCost());
            System.out.println(String.format("%s bought %s", this.name, product.getName()));
        }

    }

    @Override
    public String toString() {

        if(this.products.isEmpty()){
            return String.format("%s – Nothing bought",this.getName());
        }
        return this.getName() + " - " +
                this.products
                        .stream()
                        .map(Product::getName)
                        .collect(Collectors.joining(", "));
    }

    @Override
    public void validateNumber(double num) {
        if (num < 0) {
            throw new IllegalArgumentException("Money cannot be negative");
        }
    }

    @Override
    public void validateName(String name) {
        if (name == null || name.trim().isEmpty()) {
            throw new IllegalArgumentException("Name cannot be empty.");
        }
    }
}

Product ------------->

package E3_ShoppingSpree;

public class Product implements ValidateData {
    private String name;
    private double cost;

    public Product(String name, double cost) {
        this.setName(name);
        this.setCost(cost);
    }

    public String getName() {
        return this.name;
    }

    private void setName(String name) {
        validateName(name);
        this.name = name;
    }

    public double getCost() {

        return this.cost;
    }

    private void setCost(double cost) {
        validateNumber(cost);
        this.cost = cost;
    }

    @Override
    public void validateNumber(double num) {
        if (num < 0) {
            throw new IllegalArgumentException("Money cannot be negative");
        }
    }

    @Override
    public void validateName(String name) {
        if (name == null || name.trim().isEmpty()) {
            throw new IllegalArgumentException("Name cannot be empty.");
        }
    }
}
Validation ------>


package E3_ShoppingSpree;

public interface ValidateData {

    public void validateNumber (double num);
    public void validateName (String name);
}