An example of how to use LinkedList in Java, how to sort the items and how to display items

The following example , written in Java , shows how to use the class LinkedList. Using two classes, one to create objects of type Employee, another to create objects of type Product. To view the list of items in the list, using two different approaches: the first uses for( ), the second uses the while( ).

public class Employee implements Comparable<Object>
{
	private String surname;
	private String name;
	private int age;
	
	public Employee(String s, String n, int a)
	{
		surname = s;
		name = n;
		setAge(a);
	}
	
	public int getAge() {
		return age;
	}

	private void setAge(int age) {
		this.age = age;
	}

	public String ToString()
	{
		return surname + "\t" + name + "\t (" + getAge() + ")";
	}

	@Override
	public int compareTo(Object o) {
		return this.getAge() - (((Employee)o).getAge());
	}
}

public class Product implements Comparable<Object>
{
	private String name;
	private String brand;
	private double price;
	
	public Product(String n, String b, double p)
	{
	name = n;
	setBrand(b);
	price = p;
	}
	
	public String getBrand() {
		return brand;
	}

	private void setBrand(String brand) {
		this.brand = brand;
	}

	public String ToString()
	{
		return name + "("+getBrand()+")\t € " + price;
	}

	@Override
	public int compareTo(Object o) {
		return (int)(this.price - (((Product)o).price));
	}

}

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;

public class GenericsTest
{
	public static void main (String [] args)
	{
		// Create a LinkedList
		List<Employee> employeesList = new LinkedList<Employee>();
		
		// Fill LinkedList with some employees
		fillEmployeesList(employeesList);

		// Print the contents of the list 
		printEmployeesList(employeesList);
		
		System.out.println();
		
		// Sort employeesList
		// See compareTo(Object o) of Employees class
		Collections.sort(employeesList);
		
		// Print the contents of the list
		printEmployeesList(employeesList);
		
		System.out.println();
		
		// Create a LinkedList
		List<Product> productsList = new LinkedList<Product>();
		
		// Fill LinkedList with some products
		fillProductsList(productsList);
		
		// Print the contents of the list 
		printProductsList(productsList);
		
		System.out.println();
	
		// Sort productsList
		// See compareTo(Object o) of Products class
		Collections.sort(productsList);
		
		// Print the contents of the list
		printProductsList(productsList);
		
		System.out.println();
		
		// Display the names of employees who have more than 30 years
		System.out.println("Enter the age");
		Scanner scanner = new Scanner(System.in);
		int limitAge = scanner.nextInt(); 
		printEmployeesList(employeesList, limitAge);
		
		System.out.println();
		
		// Display the products of selected brand
		System.out.println("Enter a brand");
		String  brand = scanner.next();
		printProductsList(productsList, brand);
		
		// Close the scanner
		scanner.close();
	}

	/**
	 * Fills the list with the values of employees
	 * @param employeesList
	 */
	private static void fillEmployeesList(List<Employee> employeesList) {
		employeesList.add(new Employee("Bart", "Desy", 34));
		employeesList.add(new Employee("Stenn", "Orny", 28));
		employeesList.add(new Employee("Lust", "Barbara", 31));
		employeesList.add(new Employee("Marriot", "Bill", 36));
		employeesList.add(new Employee("Fuert", "Carl", 54));
		employeesList.add(new Employee("Cant", "Donald", 48));
		employeesList.add(new Employee("Von", "Jack", 22));
	}
	
	/**
	 * Print the list of employees
	 * @param employeesList
	 */
	private static void printEmployeesList(List<Employee> employeesList) {
		System.out.println("Employee list:".toUpperCase());
		System.out.println("Surn.\tName\tAge");
		System.out.println(".....................");

		// Print all items in the list, using for( )
		for(Employee e : employeesList) {
			System.out.println(e.ToString());
		}
	}
	
	/**
	 *  Display the names of employees who have more than 35 years
	 * @param employeesList
	 * @param limitAge
	 */
	private static void printEmployeesList(List<Employee> employeesList, int limitAge) {
		System.out.println("Employee list (Age>=".toUpperCase() + limitAge + ")");
		System.out.println("Surn.\tName\tAge");
		System.out.println(".....................");

		// Print all items in the list 
		for(Employee e : employeesList) {
			if(e.getAge()>=limitAge) {
				System.out.println(e.ToString());
			}
		}
	}
	
	/**
	 * Fills the list with the values of products
	 * @param productsList
	 */
	private static void fillProductsList(List<Product> productsList) {
		productsList.add(new Product("Netbook","LENOVO", 260.00));
		productsList.add(new Product("Desktop", "LENOVO", 780.56));
		productsList.add(new Product("Notebook", "ASUS", 560.99));
		productsList.add(new Product("Netbook","ASUS", 290.00));
		productsList.add(new Product("Netbook","ACER", 260.00));
		productsList.add(new Product("Server", "DELL", 1630.00));
		productsList.add(new Product("Notebook", "HP", 760.50));
		productsList.add(new Product("Notebook", "DELL", 633.90));
		productsList.add(new Product("Server", "HP", 1499.00));
		productsList.add(new Product("Desktop", "ACER", 680.48));
	}
	
	/**
	 * Print the list of products
	 * @param productsList
	 */
	private static void printProductsList(List<Product> productsList) {
		System.out.println("Products list:".toUpperCase());		
		System.out.println("Product\t\tPrice");
		System.out.println(".....................");
		
		// Print all items in the list, using while( )
		Iterator<Product>  itrProducts = productsList.iterator(); 
		while(itrProducts.hasNext()) {
			Product p =itrProducts.next();
			System.out.println(p.ToString());
		} 
	}
	
	/**
	 * Print the list of products
	 * @param productsList
	 */
	private static void printProductsList(List<Product> productsList, String brand) {
		System.out.println("Products list:".toUpperCase());		
		System.out.println("Product\t\tPrice");
		System.out.println(".....................");
		
		// Print all items in the list, using while( )
		Iterator<Product>  itrProducts = productsList.iterator(); 
		while(itrProducts.hasNext()) {
			Product p =itrProducts.next();
			if(p.getBrand().equals(brand)) {
				System.out.println(p.ToString());
			}
		} 
	}
}

Result:

EMPLOYEE LIST:
Surn.    Name    Age
.....................
Bart    Desy       (34)
Stenn    Orny     (28)
Lust    Barbara   (31)
Marriot    Bill      (36)
Fuert    Carl       (54)
Cant    Donald   (48)
Von    Jack        (22)

EMPLOYEE LIST:
Surn.    Name    Age
.....................
Von    Jack      (22)
Stenn    Orny   (28)
Lust    Barbara (31)
Bart    Desy     (34)
Marriot    Bill    (36)
Cant    Donald (48)
Fuert    Carl     (54)

PRODUCTS LIST:
Product        Price
.....................
Netbook(LENOVO)     € 260.0
Desktop(LENOVO)     € 780.56
Notebook(ASUS)       € 560.99
Netbook(ASUS)         € 290.0
Netbook(ACER)         € 260.0
Server(DELL)            € 1630.0
Notebook(HP)          € 760.5
Notebook(DELL)       € 633.9
Server(HP)              € 1499.0
Desktop(ACER)        € 680.48

PRODUCTS LIST:
Product        Price
.....................
Netbook(LENOVO)     € 260.0
Netbook(ACER)         € 260.0
Netbook(ASUS)         € 290.0
Notebook(ASUS)       € 560.99
Notebook(DELL)        € 633.9
Desktop(ACER)         € 680.48
Notebook(HP)           € 760.5
Desktop(LENOVO)     € 780.56
Server(HP)               € 1499.0
Server(DELL)            € 1630.0

Enter the age
15
EMPLOYEE LIST (AGE>=15)
Surn.    Name    Age
.....................
Von    Jack       (22)
Stenn    Orny    (28)
Lust    Barbara  (31)
Bart    Desy      (34)
Marriot    Bill     (36)
Cant    Donald  (48)
Fuert    Carl     (54)

Enter a brand
DELL
PRODUCTS LIST:
Product        Price
.....................
Notebook(DELL)     € 633.9
Server(DELL)         € 1630.0