The take() method of DelayQueue is used to retrieve head of the DelayQueue and also removes it. Thus, the size of the DelayQueue is reduced. This function waits if an element with expired delay is available on this queue.
Syntax:
public E take ()
Parameters: This method accepts no parameters.
Return Value: The function returns the head of the DelayQueue.
Exception: This method throws InterruptedException if interrupted while waiting.
Below programs illustrate the DelayQueue.take() method:
Program:
Java
// Java Program Demonstrate DelayQueue take() 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 ));
// print the size of DelayQueue
System.out.println( "Size of the DelayQueue: "
+ DQ.size());
// print queue
System.out.println( "DelayQueue: "
+ DQ);
// take() function will retrieve and remove the head of DelayQueue
System.out.println( "Head of the DelayQueue:"
+ DQ.take());
// print the size of DelayQueue
System.out.println( "Size of the DelayQueue: "
+ DQ.size());
// print queue
System.out.println( "DelayQueue: "
+ DQ);
}
} |
Output:
Size of the DelayQueue: 4 DelayQueue: [ { A, time=1546842594283}, { B, time=1546842594284}, { C, time=1546842594285}, { D, time=1546842594286}] Head of the DelayQueue: { A, time=1546842594283} Size of the DelayQueue: 3 DelayQueue: [ { B, time=1546842594284}, { D, time=1546842594286}, { C, time=1546842594285}]