Java CopyOnWriteArrayList containsAll()方法

Java中CopyOnWriteArrayList类的containsAll()方法用于检查该List是否包含指定集合中的所有元素。所以基本上它是用来检查List是否包含一组元素的。

语法:

boolean containsAll(Collection col)

参数 ：该方法接受一个强制性参数col，它是集合类型的。这是一个需要检查其元素是否存在于列表中的集合。

返回值 ：如果col集合中的所有元素都存在于List中，该方法返回True，否则返回False。

异常 ：如果指定的集合是空的，该方法会抛出NullPointerException。

下面的程序说明了CopyOnWriteArrayList类的containsAll（）方法。

程序1 :

// Java program to illustrate CopyOnWriteArrayList
//  containsAll() method
  
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG1 {
    public static void main(String[] args)
    {
        CopyOnWriteArrayList<String> ArrLis1
            = new CopyOnWriteArrayList<String>();
  
        // Add elements
        ArrLis1.add("geeks");
        ArrLis1.add("shaan");
        ArrLis1.add("gfg");
        ArrLis1.add("programming");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList1: " + ArrLis1);
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<String> ArrLis2
            = new CopyOnWriteArrayList<String>();
  
        // Add elements
        ArrLis2.add("geeks");
        ArrLis2.add("gfg");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList2: " + ArrLis2);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis2))
            System.out.println("All list2 elements are present in list1");
        else
            System.out.println("All list2 elements are not present in list1");
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<String> ArrLis3
            = new CopyOnWriteArrayList<String>();
  
        // Add elements
        ArrLis3.add("geeks");
        ArrLis3.add("qwe");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList3: " + ArrLis3);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis3))
            System.out.println("All list3 elements are present in list1");
        else
            System.out.println("All list3 elements are not present in list1");
    }
}

输出。

CopyOnWriteArrayList1: [geeks, shaan, gfg, programming]
CopyOnWriteArrayList2: [geeks, gfg]
All list2 elements are present in list1
CopyOnWriteArrayList3: [geeks, qwe]
All list3 elements are not present in list1

程序2 :

// Java program to illustrate CopyOnWriteArrayList
// containsAll() method
  
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG1 {
    public static void main(String[] args)
    {
        CopyOnWriteArrayList<Integer> ArrLis1
            = new CopyOnWriteArrayList<Integer>();
  
        // Add elements
        ArrLis1.add(23);
        ArrLis1.add(65);
        ArrLis1.add(91);
        ArrLis1.add(126);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList1: " + ArrLis1);
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<Integer> ArrLis2
            = new CopyOnWriteArrayList<Integer>();
  
        // Add elements
        ArrLis2.add(23);
        ArrLis2.add(126);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList2: " + ArrLis2);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis2))
            System.out.println("All list2 elements are present in list1");
        else
            System.out.println("All list2 elements are not present in list1");
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList<Integer> ArrLis3
            = new CopyOnWriteArrayList<Integer>();
  
        // Add elements
        ArrLis3.add(23);
        ArrLis3.add(92);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList3: " + ArrLis3);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis3))
            System.out.println("All list3 elements are present in list1");
        else
            System.out.println("All list3 elements are not present in list1");
    }
}

输出。

CopyOnWriteArrayList1: [23, 65, 91, 126]
CopyOnWriteArrayList2: [23, 126]
All list2 elements are present in list1
CopyOnWriteArrayList3: [23, 92]
All list3 elements are not present in list1

参考资料 : https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/CopyOnWriteArrayList.html#containsAll(java.util.Collection)