Java 中的 CopyOnWriteArraySet isEmpty()方法

原文:https://www . geeksforgeeks . org/copy onwriterarrayset-isempty-method-in-Java/

是 的空方法 检查集合是否为空。如果集合为空，则返回真，否则返回假。

语法:

public boolean isEmpty()

返回值:如果集合为空，则函数返回真，否则返回假。

以下程序说明了上述功能:

程序 1:

Java 语言(一种计算机语言，尤用于创建网站)

// Java Program to illustrate the
// isEmpty() method in CopyOnWriteArraySet

import java.util.concurrent.CopyOnWriteArraySet;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // create object of CopyOnWriteArraySet
        CopyOnWriteArraySet<Integer> ArrSet
            = new CopyOnWriteArraySet<Integer>();

        // Add elements
        ArrSet.add(32);
        ArrSet.add(67);
        ArrSet.add(98);
        ArrSet.add(100);

        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: " + ArrSet);

        // check using function
        if (ArrSet.isEmpty())
            System.out.println("\nSet is empty");
        else
            System.out.println("\nSet is not empty");
    }
}

Output: 

CopyOnWriteArraySet: [32, 67, 98, 100]

Set is not empty

程序 2:

Java 语言(一种计算机语言，尤用于创建网站)

// Java Program to illustrate the
// isEmpty() method in CopyOnWriteArraySet
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.*;

public class GFG {
    public static void main(String[] args)
    {

        // create object of CopyOnWriteArraySet
        CopyOnWriteArraySet<String> ArrSet
            = new CopyOnWriteArraySet<String>();

        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet);

        // check using function
        if (ArrSet.isEmpty())
            System.out.println("\nSet is empty");
        else
            System.out.println("\nSet is not empty");
    }
}

Output: 

CopyOnWriteArraySet: []

Set is empty

参考:T2【https://docs . Oracle . com/javase/8/docs/API/Java/util/concurrent/copy onwriterarrayset . html # isEmpty–T4】

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