https://raw.githubusercontent.com/vsaravanan/java22/master/src/main/java/com/saravanjs/java22/console/collection/ProrityQueueObject.java









/*



    PriorityQueue is a type of queue in Java that orders its elements according to their natural ordering

    (if they implement Comparable) or by a Comparator provided at queue construction time.





 */

@Data

class Employee  {
 private String name;
 private int salary;


 public Employee(String name, int salary) {
 this.name = name;
 this.salary = salary;

    }


 @Override
 public String toString() {
 return "Employee [name=" + name + ", salary=" + salary + "] \n";

    }



}





class EmpComparator implements Comparator<Employee> {
 @Override
 public int compare(Employee o1, Employee o2) {
 return o1.getSalary() - o2.getSalary();

    }

}



public class ProrityQueueObject {
 public static void main(String[] args) {
 Employee e1 = new Employee("Sarav", 300);
 Employee e2 = new Employee("Raj", 200);
 Employee e3 = new Employee("Ravi", 4000);
 Employee e4 = new Employee("Rahul", 50);
 Employee e5 = new Employee("Juhi", 10);


 EmpComparator comparator = new EmpComparator();


 PriorityQueue<Employee > pq = new PriorityQueue<>(5, comparator);
 pq.add(e1);
 pq.add(e2);
 pq.add(e3);
 pq.add(e4);
 pq.add(e5);
 pq.add(new Employee("F", 3500));
 pq.add(new Employee("G", 50000));




 System.out.println("peek " +  pq.peek());


 System.out.println(pq);


 System.out.println("for loop will not print in sorted order");
 for (Employee e : pq) {
 System.out.println(e);

        }


 System.out.println("use sorted comparator to get sorted order");
 pq.stream().sorted(comparator).forEach(System.out::println);


 while (! pq.isEmpty()) {
 System.out.println("polled " + pq.poll());
 System.out.println(pq);
 System.out.println("-----------------------------------------------------");

        }



    }

}




 
peek Employee [name=Juhi, salary=10] 
 
[Employee [name=Juhi, salary=10] 
, Employee [name=Rahul, salary=50] 
, Employee [name=F, salary=3500] 
, Employee [name=Sarav, salary=300] 
, Employee [name=Raj, salary=200] 
, Employee [name=Ravi, salary=4000] 
, Employee [name=G, salary=50000] 
]
for loop will not print in sorted order
Employee [name=Juhi, salary=10] 
 
Employee [name=Rahul, salary=50] 
 
Employee [name=F, salary=3500] 
 
Employee [name=Sarav, salary=300] 
 
Employee [name=Raj, salary=200] 
 
Employee [name=Ravi, salary=4000] 
 
Employee [name=G, salary=50000] 
 
use sorted comparator to get sorted order
Employee [name=Juhi, salary=10] 
 
Employee [name=Rahul, salary=50] 
 
Employee [name=Raj, salary=200] 
 
Employee [name=Sarav, salary=300] 
 
Employee [name=F, salary=3500] 
 
Employee [name=Ravi, salary=4000] 
 
Employee [name=G, salary=50000] 
 
polled Employee [name=Juhi, salary=10] 
 
[Employee [name=Rahul, salary=50] 
, Employee [name=Raj, salary=200] 
, Employee [name=F, salary=3500] 
, Employee [name=Sarav, salary=300] 
, Employee [name=G, salary=50000] 
, Employee [name=Ravi, salary=4000] 
]
-----------------------------------------------------
polled Employee [name=Rahul, salary=50] 
 
[Employee [name=Raj, salary=200] 
, Employee [name=Sarav, salary=300] 
, Employee [name=F, salary=3500] 
, Employee [name=Ravi, salary=4000] 
, Employee [name=G, salary=50000] 
]
-----------------------------------------------------
polled Employee [name=Raj, salary=200] 
 
[Employee [name=Sarav, salary=300] 
, Employee [name=Ravi, salary=4000] 
, Employee [name=F, salary=3500] 
, Employee [name=G, salary=50000] 
]
-----------------------------------------------------
polled Employee [name=Sarav, salary=300] 
 
[Employee [name=F, salary=3500] 
, Employee [name=Ravi, salary=4000] 
, Employee [name=G, salary=50000] 
]
-----------------------------------------------------
polled Employee [name=F, salary=3500] 
 
[Employee [name=Ravi, salary=4000] 
, Employee [name=G, salary=50000] 
]
-----------------------------------------------------
polled Employee [name=Ravi, salary=4000] 
 
[Employee [name=G, salary=50000] 
]
-----------------------------------------------------
polled Employee [name=G, salary=50000] 
 

[]

 
 
 
 


https://raw.githubusercontent.com/vsaravanan/java22/master/src/main/java/console/collection/PriorityQueueExample.java




class Task implements Comparable<Task> {
 private String name;
 private int priority;


 public Task(String name, int priority) {
 this.name = name;
 this.priority = priority;

    }


 public String getName() {
 return name;

    }


 public int getPriority() {
 return priority;

    }


 @Override
 public int compareTo(Task other) {
 return Integer.compare(this.priority, other.priority);

    }


 @Override
 public String toString() {
 return "Task{" +
 "name='" + name + '\'' +
 ", priority=" + priority +
 '}';

    }

}



public class PriorityQueueExample {
 public static void main(String[] args) {
 // Create a PriorityQueue
 PriorityQueue<Task> taskQueue = new PriorityQueue<>();


 // Add tasks to the queue
 taskQueue.add(new Task("Write report", 2));
 taskQueue.add(new Task("Attend meeting", 1));
 taskQueue.add(new Task("Complete assignment", 3));


 // Process tasks in priority order
 while (!taskQueue.isEmpty()) {
 Task task = taskQueue.poll();
 System.out.println("Processing task: " + task);

        }

    }

}
 
 
Processing task: Task{name='Attend meeting', priority=1}
Processing task: Task{name='Write report', priority=2}
Processing task: Task{name='Complete assignment', priority=3}