Java中的CopyOnWriteArraySet removeIf()方法示例

CopyOnWriteArraySet方法中的 removeIf() 方法将满足指定条件的元素从CopyOnWriteArraySet中删除。

语法:

public boolean removeIf(Predicate<E>filter)

参数: 该方法接受一个必填参数filter，该参数是基于谓词值，用于从该集合中删除元素。

返回值: 如果CopyOnWriteArraySet已更改，则此方法返回布尔值（例如true）。否则，此方法将返回false。

异常: 如果指定的Predicate filter为null，则此方法将抛出 NullPointerException 。

以下程序说明了CopyOnWriteArrayList类的removeIf()函数：

程序1:

// Java Program to illustrate the CopyOnWriteArraySet
// removeIf() method in Java
        
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(10);
        ArrSet.add(20);
        ArrSet.add(30);
        ArrSet.add(40);
        ArrSet.add(50);
        ArrSet.add(60);
        ArrSet.add(70);
        ArrSet.add(80);
        ArrSet.add(90);
        
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet);
        
        // if a number in the set is
        // divisible by 3, then remove it
        ArrSet.removeIf(number -> number % 3 == 0);
        
        // print updated CopyOnWriteArraySet
        System.out.println("Updated CopyOnWriteArraySet: "
                           + ArrSet);
    }
}

CopyOnWriteArraySet: [10, 20, 30, 40, 50, 60, 70, 80, 90]
Updated CopyOnWriteArraySet: [10, 20, 40, 50, 70, 80]

程序2:

// Java Program to illustrate the CopyOnWriteArraySet
// removeIf() method in Java
        
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>();
        
        // Add elements
        ArrSet.add("GeeksforGeeks");
        ArrSet.add("GFG");
        ArrSet.add("Geeks");
        ArrSet.add("Gfg");
        
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet: "
                           + ArrSet);
        
        try {
        
            // if a number in the set is
            // divisible by 3, then remove it
            // This will throw NullPointerException
            ArrSet.removeIf(null);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出：

CopyOnWriteArraySet: [GeeksforGeeks, GFG, Geeks, Gfg]
java.lang.NullPointerException