Java 中的 DelayQueue take()方法，示例
原文:https://www . geeksforgeeks . org/delay queue-take-method-in-Java-with-examples/
延迟队列的 take() 方法用于检索延迟队列的头部并将其移除。因此，延迟队列的大小减小了。如果此队列中有延迟过期的元素，此函数将等待。 语法:
public E take ()
参数:该方法不接受参数。 返回值:该函数返回延迟队列的头部。 异常:如果在等待时被中断，此方法会抛出中断异常。 下面的程序说明了 DelayQueue.take()方法: 程序:
Java 语言(一种计算机语言，尤用于创建网站)
// 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}]
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