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Java DelayQueue take()用法及代码示例


DelayQueue的take()方法用于检索DelayQueue的头部,也将其删除。因此,减小了DelayQueue的大小。如果此队列上有延迟过期的元素可用,则此函数等待。
用法:

public E take ()

参数:此方法不接受任何参数。

返回值:该函数返回DelayQueue的头部。


异常:如果在等待期间被中断,则此方法将引发InterruptedException。

以下示例程序旨在说明DelayQueue.take()方法:

程序:

// 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; 
  
    // Contructor 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); 
    } 
}
输出:
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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注:本文由纯净天空筛选整理自ProgrammerAnvesh大神的英文原创作品 DelayQueue take() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。