Java LinkedBlockingDeque getFirst() 方法

2025 年 3 月 21 日 | 阅读 2 分钟

LinkedBlockingDeque 类的 getFirst() 方法会返回此双端队列的第一个元素，但不会将其移除。

语法

参数

不适用

指定者：

LinkedBlockingDeque 类的 getFirst() 方法是在 Deque<E> 接口中通过 getFirst() 方法指定的。

返回值

getFirst() 方法返回此双端队列的第一个元素。

抛出

如果此双端队列为空，则 getFirst() 方法会抛出 NoSuchElementException 异常。

示例 1

import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeGetFirstExample1 {
    public static void main(String[] args) {
        int capacity = 200;
        LinkedBlockingDeque<Integer> lbdeque = new LinkedBlockingDeque<Integer>(capacity);
        
        lbdeque.add(987);
        lbdeque.add(445);
        lbdeque.add(258);
        lbdeque.add(741);
        lbdeque.add(963);
        lbdeque.add(852);
        
        System.out.println("First element in the Queue is : "+lbdeque.getFirst());
    }
}

输出

First element in the Queue is : 987

示例 2

import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeGetFirstExample2 {
 public static void main(String[] args) {
  int capacity = 100;
  LinkedBlockingDeque<String> lbdeque = new linkedBlockingDeque<String>(capacity);
        lbdeque.add("Joseph");
        lbdeque.add("Marry");
        lbdeque.add("Christiano");
        lbdeque.add("Russel");
        
        lbdeque.clear();
        
        System.out.println("First element in the Queue is : "+lbdeque.getFirst());
    }
}

输出

Exception in thread "main" java.util.NoSuchElementException
	at java.util.concurrent.LinkedBlockingDeque.getFirst(Unknown Source)

示例 3

import java.util.concurrent.LinkedBlockingDeque;
class Employee{
    String name;
    int bonus_points;
    public Employee(int bonus_points,String name) {
        this.name = name;
        this.bonus_points = bonus_points;
    }
    public String toString(){
        return name +" got "+ bonus_points+" bonus_points.";
    }
}
public class LinkedBlockingDequeGetFirstExample3 {
    public static void main(String[] args) {
        Employee employee1 = new Employee(41,"Mansi");
        Employee employee2 = new Employee(33,"Vaibhav");
        Employee employee3 = new Employee(31,"Shraddha");
        Employee employee4 = new Employee(27,"Vishal");
        Employee employee5 = new Employee(26,"Shalu");
        Employee employee6 = new Employee(19,"Abhi");
        int capacity =100;	
        LinkedBlockingDeque<Employee> deque = new LinkedBlockingDeque<Employee>(capacity);
        deque.add(employee1);
        deque.add(employee2);
        deque.add(employee3);
        deque.add(employee4);
        deque.add(employee5);
        deque.add(employee6);
        for (Employee xyz : deque){
            System.out.println(xyz);
        }
        System.out.println();
        System.out.println("On the basis of bonus points, Promotion is awarded to : "+deque.element().name);
    }
}

输出

Mansi got 41 bonus_points.
Vaibhav got 33 bonus_points.
Shraddha got 31 bonus_points.
Vishal got 27 bonus_points.
Shalu got 26 bonus_points.
Abhi got 19 bonus_points.

On the basis of bonus points, Promotion is awarded to : Mansi

下一主题Java Linkedblockingdeque

Java LinkedBlockingDeque getFirst() 方法

语法

参数

指定者：

返回值

抛出

示例 1

示例 2

示例 3

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Java LinkedBlockingDeque getFirst() 方法

语法

参数

指定者：

返回值

抛出

示例 1

示例 2

示例 3

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