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Java ConcurrentLinkedDeque offer()用法及代码示例


java.util.concurrent.ConcurrentLinkedDeque.offer()方法是Java中的内置方法,它将作为参数传递的指定元素插入双端队列。

用法:

public boolean offer(E elem)

参数:该方法接受参数elem,以选择要插入双端队列的元素。


返回值:如果将元素成功添加到双端队列中,则该函数返回True,否则返回False。

异常:如果传递的参数为NULL,则该函数将引发NullPointerException。

以下示例程序旨在说明ConcurrentLinkedDeque.offer()方法:

程序1

// Java Program to Demonstrate offer() 
// method of ConcurrentLinkedDeque 
  
import java.util.concurrent.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty Deque 
        ConcurrentLinkedDeque<String> cld 
            = new ConcurrentLinkedDeque<String>(); 
  
        // Add elements into the Deque 
        cld.add("Welcome"); 
        cld.add("To"); 
        cld.add("Geeks"); 
        cld.add("4"); 
        cld.add("Geeks"); 
  
        // Displaying the Deque 
        System.out.println("ConcurrentLinkedDeque: "
                           + cld); 
  
        // Insert an element using offer() 
        if (cld.offer("GFG")) { 
  
            // Displaying message 
            System.out.println("Element Inserted"); 
        } 
        else { 
  
            // Displaying message 
            System.out.println("Element not Inserted"); 
        } 
  
        // Displaying the Deque 
        System.out.println("ConcurrentLinkedDeque: "
                           + cld); 
    } 
}
输出:
ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks]
Element Inserted
ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks, GFG]
// Java Program to Demonstrate offer() 
// method of ConcurrentLinkedDeque 
  
import java.util.concurrent.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty Deque 
        ConcurrentLinkedDeque<String> cld 
            = new ConcurrentLinkedDeque<String>(); 
  
        // Add elements into the Deque 
        cld.add("Welcome"); 
        cld.add("To"); 
        cld.add("Geeks"); 
        cld.add("4"); 
        cld.add("Geeks"); 
  
        // Displaying the Deque 
        System.out.println("ConcurrentLinkedDeque: "
                           + cld); 
  
        try { 
  
            // Insert null element using offer() 
            cld.offer(null); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}
输出:
ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks]
java.lang.NullPointerException

参考: https://docs.oracle.com/javase/9/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html#offer-E-



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注:本文由纯净天空筛选整理自Aishwarya Jayashankar大神的英文原创作品 ConcurrentLinkedDeque 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。