05. Filter by Age

package Lekciq;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.function.BiPredicate;
import java.util.function.Function;

public class FilterByAge {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);


        // Read number of entries
        int n = Integer.parseInt(scanner.nextLine());

        // Read name and age pairs
        List<Person> people = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            String[] input = scanner.nextLine().split(", ");
            String name = input[0];
            int age = Integer.parseInt(input[1]);
            people.add(new Person(name, age));
        }

        // Read condition, age, and format
        String condition = scanner.nextLine();
        int ageLimit = Integer.parseInt(scanner.nextLine());
        String format = scanner.nextLine();

        // Define predicates and functions
        BiPredicate<Integer, Integer> ageCondition = getAgeCondition(condition);
        Function<Person, String> formatFunction = getFormatFunction(format);

        // Filter and print results
        people.stream()
                .filter(person -> ageCondition.test(person.age, ageLimit))
                .map(formatFunction)
                .forEach(System.out::println);
    }

    // Method to get age condition predicate
    private static BiPredicate<Integer, Integer> getAgeCondition(String condition) {
        if (condition.equals("younger")) {
            return (age, limit) -> age <= limit;
        } else if (condition.equals("older")) {
            return (age, limit) -> age >= limit;
        } else {
            throw new IllegalArgumentException("Invalid condition: " + condition);
        }
    }

    // Method to get format function
    private static Function<Person, String> getFormatFunction(String format) {
        switch (format) {
            case "name":
                return person -> person.name;
            case "age":
                return person -> String.valueOf(person.age);
            case "name age":
                return person -> person.name + " - " + person.age;
            default:
                throw new IllegalArgumentException("Invalid format: " + format);
        }
    }

    // Person class to store name and age
    private static class Person {
        String name;
        int age;

        Person(String name, int age) {
            this.name = name;
            this.age = age;
        }
    }
}