how to add some other collection to PriorityQueue collection using collections in java
how to add some other collection to PriorityQueue collection using collections in java
| Previous | Home | Next |
In this example we are going to add some other collection that extends List to the given PriorityQueue.
For creating a PriorityQueue first of all we have to import the java.util package in which the java.util.PriorityQueue class is defined. In this example we have created a class named CollectionsExample in which we created an object of the PriorityQueue and added some elements to the queue.
In this example we used the addAll(Collection coll) method on the object of the PriorityQueue whose syntax is given as,
boolean addAll(Collection coll)
The above method appends all of the elements in the specified Collection to the end of this list, in the order that they are returned by the specified Collection's Iterator.
We have also created a user defined method named AddCollection(PriorityQueue pq, LinkedList list) which takes the PriorityQueue object and LinkedList object as its parameters. This method will add all the contents of the LinkedList to the given PriorityQueue.
We have also used the put(Object obj) method for adding the elements to the PriorityQueue.
We have created a class named CollectionsExample in which we have created a PriorityQueue object pq and added some elements to it by using the add(Object obj) method on it. We have also created a LinkedList object list and then called the AddCollection(pq, list) method.
Inside the AddCollection(pq, list), we have added elements to the LinkedList by using the add(Object obj) on its object i.e list.
After that, we have used the addAll(Collectio coll) method on the object of the PriorityQueue and passing the LinkedList object as its parameter, which is shown as in our example,
pq.addAll(list);
Finally we have displayed the contents of the PriorityQueue after the addition of the LinkedList elements to it.
package r4r.co.in;
import java.util.*;
public class CollectionsExample {
/**
* @param args
*/
public static void main(String[] args) throws NullPointerException, ClassCastException
{
// TODO Auto-generated method stub
try
{
PriorityQueue<Integer> pq=new PriorityQueue<Integer>();
pq.add(1); // adding some random values to priorityqueue pq
pq.add(2);
pq.add(3);
pq.add(4);
pq.add(5);
System.out.println("The contents of the PriorityQueue are: "+pq);
Iterator<Integer> itr=pq.iterator(); //invoking the iterator over the pq
System.out.println("The elements in the priority queue are: ");
while(itr.hasNext())
{
System.out.println(itr.next()); // displaying the elements of the queue
}
List<Integer> list=new LinkedList<Integer>(); // creating the LinkedList using the List object
AddCollection(pq, list); // calling the AddCollection method defined below, for adding list collection to priorityqueue
}
catch(NullPointerException e)
{
e.printStackTrace();
}
catch(ClassCastException e)
{
e.printStackTrace();
}
}
/* The following method add a list collection to the PriorityQueue collection */
/* This method takes two arguments viz. PriorityQueue object and List object */
private static void AddCollection(PriorityQueue<Integer> pq, List<Integer> list)
{
list.add(6); // adding elements to the List
list.add(7);
list.add(8);
list.add(9);
list.add(10);
pq.addAll(list); // adding all the List elements to the PriorityQueue
Iterator<Integer> itr=pq.iterator(); // Invoking the iterator on the priority queue
System.out.println("After adding the list collection to PriorityQueue now it conatins elements: ");
while(itr.hasNext())
{
System.out.println(itr.next()); // displaying the elements of the queue
}
}
}
The output of the above example is shown as:
The contents of the PriorityQueue are: [1, 2, 3, 4, 5]
The elements in the priority queue are:
1
2
3
4
5
After adding the list collection to PriorityQueue now it conatins elements:
1
2
3
4
5
6
7
8
9
10
| Previous | Home | Next |