The Generic Queue Class
import java.util.LinkedList;
class GenQueue<E> {
private LinkedList<E> list = new LinkedList<E>();
public void enqueue(E item) {
list.addLast(item);
}
public E dequeue() {
return list.poll();
}
public boolean hasItems() {
return !list.isEmpty();
}
public int size() {
return list.size();
}
public void addItems(GenQueue<? extends E> q) {
while (q.hasItems())
list.addLast(q.dequeue());
}
}
public class GenQueueTest {
public static void main(String[] args) {
GenQueue<Employee> empList;
empList = new GenQueue<Employee>();
GenQueue<HourlyEmployee> hList;
hList = new GenQueue<HourlyEmployee>();
hList.enqueue(new HourlyEmployee("T", "D"));
hList.enqueue(new HourlyEmployee("G", "B"));
hList.enqueue(new HourlyEmployee("F", "S"));
empList.addItems(hList);
while (empList.hasItems()) {
Employee emp = empList.dequeue();
System.out.println(emp.firstName + " " + emp.lastName);
}
}
}
class Employee {
public String lastName;
public String firstName;
public Employee() {
}
public Employee(String last, String first) {
this.lastName = last;
this.firstName = first;
}
public String toString() {
return firstName + " " + lastName;
}
}
class HourlyEmployee extends Employee {
public double hourlyRate;
public HourlyEmployee(String last, String first) {
super(last, first);
}
}
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