Java CopyOnWriteArrayList set()用法及代碼示例

類CopyOnWriteArrayList類中的set(E e)方法將指定索引處的元素替換為作為該方法的參數提供的元素。該方法返回已被新元素替換的元素。

用法:

public E set(int index, E element)

參數：該方法采用以下兩個參數：

Index：包含新元素替換現有元素的位置。必須添加。
Element：包含要替換的新元素。

返回值：該方法返回已替換的元素。

異常：當方法的索引小於0或大於列表的大小時，將發生方法拋出IndexOutOfBoundsException。

下麵是一些程序，用於說明CopyOnWriteArrayList.set()方法的使用：

示例1:

// Program to illustrate the use of set() method 
  
import java.util.concurrent.CopyOnWriteArrayList; 
  
public class CopyOnWriteArrayListDemo { 
    public static void main(String[] args) 
    { 
  
        // creating an ArrayList 
        CopyOnWriteArrayList<String> arrayList 
            = new CopyOnWriteArrayList<String>(); 
  
        // Adding elements to the list 
        arrayList.add(0, "geeks"); 
        arrayList.add(1, "for"); 
        arrayList.add(2, "geeksforgeeks"); 
  
        // before invoking the set() method 
        System.out.println("CopyOnWriteArrayList: "
                           + arrayList); 
  
        // invoking the set() method 
        String returnValue 
            = arrayList.set(0, "toodles"); 
  
        // printing the returned value 
        System.out.println("The value returned "
                           + "on caling set() method:"
                           + returnValue); 
  
        // print CopyOnWriteArrayList 
        System.out.println("CopyOnWriteArrayList "
                           + "after calling set():"
                           + arrayList); 
    } 
}

輸出：

CopyOnWriteArrayList: [geeks, for, geeksforgeeks]

The value returned on caling set() method: geeks

CopyOnWriteArrayList after calling set(): [toodles, for, geeksforgeeks]

示例2:

// Program to illustrate the ArrayIndexOutOfBoundsException 
  
import java.util.concurrent.CopyOnWriteArrayList; 
  
public class CopyOnWriteArrayListDemo { 
    public static void main(String[] args) 
    { 
  
        // creating an ArrayList 
        CopyOnWriteArrayList<String> arrayList 
            = new CopyOnWriteArrayList<String>(); 
  
        // Adding elements to the list 
        arrayList.add(0, "geeks"); 
        arrayList.add(1, "for"); 
        arrayList.add(2, "geeksforgeeks"); 
  
        // before invoking the set() method 
        System.out.println("CopyOnWriteArrayList: "
                           + arrayList); 
  
        try { 
  
            System.out.println("Trying to add "
                               + "element at index 4 "
                               + "usiung set() method"); 
  
            // invoking the set() method 
            String returnValue 
                = arrayList.set(4, "toodles"); 
            // printing the returned value 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

CopyOnWriteArrayList: [geeks, for, geeksforgeeks]
Trying to add element at index 4 usiung set() method

java.lang.ArrayIndexOutOfBoundsException: 4

相關用法

注：本文由純淨天空篩選整理自DeepaliK1大神的英文原創作品 CopyOnWriteArrayList set() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。