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() methodimport java.util.concurrent.*;import java.util.*;// The DelayObject for DelayQueue// It must implement Delayed and// its getDelay() and compareTo() methodclass 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 Classpublic 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}]
