Java 中的 ConcurrentLinkedQueue addAll()方法
原文:https://www . geeksforgeeks . org/concurrentlinkedqueue-addall-method-in-Java/
ConcurrentLinkedQueue 的 addAll() 方法用于在 ConcurrentLinkedQueue 的末尾插入集合的所有元素，作为参数传递给该方法。元素的插入顺序与集合迭代器返回的顺序相同。
语法:
public boolean addAll(Collection<? extends E> c)
参数:这个方法取一个参数 c ，这个参数代表一个集合，这个集合的元素需要被追加到这个 ConcurrentLinkedQueue 的末尾。
返回:如果至少执行了一个插入动作，该方法返回真。
异常:这个方法抛出两个不同的异常:
- [null pointer exception] -If the passed set or any of its elements is null.
- illegalargumentexception –If the passed collection is the queue itself.
下面的程序说明了并发链接队列的 addAll()方法:
示例 1: 试图向 ConcurrentLinkedQueue 添加数字列表。
// Java Program Demonstrate addAll()
// method of ConcurrentLinkedQueue
import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<Integer>
queue = new ConcurrentLinkedQueue<Integer>();
// Add Numbers to queue
queue.add(4353);
// create a ArrayList of Numbers
ArrayList<Integer> arraylist = new ArrayList<Integer>();
// add some numbers to ArrayList
arraylist.add(377139);
arraylist.add(624378);
arraylist.add(654793);
arraylist.add(764764);
arraylist.add(838494);
arraylist.add(632845);
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
// Displaying the existing Collection
System.out.println("Collection to be added: " + arraylist);
// apply addAll() method and passed the arraylist as parameter
boolean response = queue.addAll(arraylist);
// Displaying the existing ConcurrentLinkedQueue
System.out.println("Collection added: " + response);
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
}
}
输出:
ConcurrentLinkedQueue: [4353]
Collection to be added: [377139, 624378, 654793, 764764, 838494, 632845]
Collection added: true
ConcurrentLinkedQueue: [4353, 377139, 624378, 654793, 764764, 838494, 632845]
示例 2: 试图向 ConcurrentLinkedQueue 添加字符串列表。
// Java Program Demonstrate addAll()
// method of ConcurrentLinkedQueue
import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add("Aman");
queue.add("Amar");
// create a ArrayList of Numbers
ArrayList<String> arraylist = new ArrayList<String>();
// add some numbers to ArrayList
arraylist.add("Sanjeet");
arraylist.add("Rabi");
arraylist.add("Debasis");
arraylist.add("Raunak");
arraylist.add("Mahesh");
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
// Displaying the existing Collection
System.out.println("Collection to be added: " + arraylist);
// apply addAll() method and passed the arraylist as parameter
boolean response = queue.addAll(arraylist);
// Displaying the existing ConcurrentLinkedQueue
System.out.println("Collection added: " + response);
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
}
}
输出:
ConcurrentLinkedQueue: [Aman, Amar]
Collection to be added: [Sanjeet, Rabi, Debasis, Raunak, Mahesh]
Collection added: true
ConcurrentLinkedQueue: [Aman, Amar, Sanjeet, Rabi, Debasis, Raunak, Mahesh]
示例 3: 显示空指针异常
// Java Program Demonstrate addAll()
// method of ConcurrentLinkedQueue
import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add("Aman");
queue.add("Amar");
// create a ArrayList which is equal to null
ArrayList<String> arraylist = null;
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
// Displaying the existing Collection
System.out.println("Collection to be added: " + arraylist);
try {
// apply addAll() method and pass the arraylist as parameter
// since the arraylist is null, exception will be thrown
boolean response = queue.addAll(arraylist);
}
catch (NullPointerException e) {
System.out.println("Exception thrown while adding null: " + e);
}
}
}
输出:
ConcurrentLinkedQueue: [Aman, Amar]
Collection to be added: null
Exception thrown while adding null: java.lang.NullPointerException
示例 4: 显示 IllegalArgumentException
// Java Program Demonstrate addAll()
// method of ConcurrentLinkedQueue
import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add("Aman");
queue.add("Amar");
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
try {
// apply addAll() method and passed the queue as parameter
boolean response = queue.addAll(queue);
}
catch (IllegalArgumentException e) {
System.out.println("Exception thrown while adding queue"
+ " to itself when collection is required: " + e);
}
}
}
输出:
ConcurrentLinkedQueue: [Aman, Amar]
Exception thrown
while adding queue to itself
when collection is required: java.lang.IllegalArgumentException
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