The iterator() method of DelayQueue is used to return an iterator over all the elements in the DelayQueue. These elements can be expired or unexpired.
Syntax:
public Iterator iterator ()
Parameters: This method does not accept any parameter.
Returns: This method returns an iterator over elements in this delayqueue.
Below program to illustrate DelayQueue iterator() in Java:
Example:
Java
// Java Program Demonstrate DelayQueue iterator() method import java.util.concurrent.*;
import java.util.*;
// The DelayObject for DelayQueue // It must implement Delayed and // its getDelay() and compareTo() method class DelayObject implements Delayed {
private String name;
private long time;
// Constructor of DelayObject
public DelayObject(String name, long delayTime)
{
this .name = name;
this .time = System.currentTimeMillis()
+ delayTime;
}
// Implementing getDelay() method of Delayed
@Override
public long getDelay(TimeUnit unit)
{
long diff = time - System.currentTimeMillis();
return unit.convert(diff, TimeUnit.MILLISECONDS);
}
// Implementing compareTo() method of Delayed
@Override
public int compareTo(Delayed obj)
{
if ( this .time < ((DelayObject)obj).time) {
return - 1 ;
}
if ( this .time > ((DelayObject)obj).time) {
return 1 ;
}
return 0 ;
}
// Implementing toString() method of Delayed
@Override
public String toString()
{
return "\n{"
+ " " + name + ", time=" + time + "}" ;
}
} // Driver Class public class GFG {
public static void main(String[] args) throws InterruptedException
{
// create object of DelayQueue
// using DelayQueue() constructor
BlockingQueue<DelayObject> DQ
= new DelayQueue<DelayObject>();
// Add numbers to end of DelayQueue
// using add() method
DQ.add( new DelayObject( "A" , 1 ));
DQ.add( new DelayObject( "B" , 2 ));
DQ.add( new DelayObject( "C" , 3 ));
DQ.add( new DelayObject( "D" , 4 ));
// Creating an iterator
Iterator val = DQ.iterator();
// print the value after iterating DelayQueue
System.out.println( "The iterator values are: " );
while (val.hasNext()) {
System.out.println(val.next());
}
}
} |
Output:
The iterator values are: { A, time=1545818784540} { B, time=1545818784541} { C, time=1545818784542} { D, time=1545818784543}