Why Iterator doesn't iterators according to elements priority ?

[Parthiban Malayandi]

Hi all,

I have a question in PriorityQueue collection.
Here's the program I tried to understand it

import java.util.*;
 
public class QueueExample {
public static void main(String[] args) {
Queue<String> strQ= new PriorityQueue<String>();

String[] str = {"z","a","g","c","b","j","i"};

for(String s:str){
strQ.offer(s);
}

Iterator iterator = strQ.iterator();

System.out.println("Using iterator to print elements of queue");
while(iterator.hasNext()){
System.out.print(iterator.next()+" ");
}

System.out.println();

System.out.println("Viewing the elements using poll() method "); 
for(String s:str){
System.out.print(strQ.poll()+" ");
}

}
}
 

Output :
========

Using iterator to print elements of queue
a b g z c j i
Viewing the elements using poll() method
a b c g i j z

I learned that using a no-arg constructor of PriorityQueue uses the comparator to order it's elements according to it's natural ordering.

I can see this when I invoke poll() method on it but why I use Iterator to iterate its elements it's not iterating in that order (not even in the order when I inserted ) .



Can any one tell me on what basis Iterator iterates the element ?

Thanks in advance
[ October 18, 2008: Message edited by: Parthiban Mahiby ]

[Ankit Garg]

see this...

[Parthiban Malayandi]

Hi Ankit,
Thanks for your reply.got it.