DelayQueue的offer()方法用于在延迟队列中插入指定的元素。它的作用类似于DelayQueue的add()方法。
用法:
public boolean offer (E e)
参数:
DelayQueue仅接受属于Delayed类型的那些元素。因此,此元素E的类型应为Delayed。
返回值:
此方法不返回任何内容。
异常:
NullPointerException :如果指定的元素为null。
下面的程序来说明Java中的DelayQueue offer():
例:
// Java Program Demonstrate DelayQueue offer() 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));
// Print delayqueue
System.out.println("Original DelayQueue: "
+ DQ + "\n");
// Now insert elements using offer method
DQ.offer(new DelayObject("C", 10));
DQ.offer(new DelayObject("D", 11));
DQ.offer(new DelayObject("E", 15));
DQ.offer(new DelayObject("F", 17));
// print queue
System.out.println("After insertion DelayQueue: "
+ DQ);
}
}
输出:
Original DelayQueue: [ { A, time=1545817395066}, { B, time=1545817395067}] After insertion DelayQueue: [ { A, time=1545817395066}, { B, time=1545817395067}, { C, time=1545817395076}, { D, time=1545817395077}, { E, time=1545817395081}, { F, time=1545817395083}]
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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 offer() 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。