Java CopyOnWriteArraySet equals()方法

CopyOnWriteArraySet 的 equals(Object O) 方法比较指定的对象和这个集合是否相等。如果指定的对象与这个对象相同，或者它也是一个集合，并且指定集合上的迭代器返回的元素与这个集合上的迭代器返回的元素相同，则返回真。更正式地说，如果两个迭代器返回相同数量的元素，并且对于指定集合上的迭代器返回的每一个元素e1，这个集合上的迭代器都有一个元素e2，并且(e1==null ? e2==null : e1.e2 equals(e2))，则被认为返回相同的元素。

语法

public boolean equals(Object O)

参数: 这个函数接受一个强制参数Object O ，它是要与CopyOnWriteArraySet进行比较的对象。

返回值： 如果被比较的对象等于这个Set，该函数返回true。

程序1 :

// Java Program to illustrate the
// equals() 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> ArrSet1
            = new CopyOnWriteArraySet<Integer>();
 
        // Add elements
        ArrSet1.add(32);
        ArrSet1.add(67);
        ArrSet1.add(98);
        ArrSet1.add(100);
 
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet 1: "
                           + ArrSet1);
 
        // create object of CopyOnWriteArraySet
        CopyOnWriteArraySet<Integer> ArrSet2
            = new CopyOnWriteArraySet<Integer>();
 
        // Add elements
        ArrSet2.add(32);
        ArrSet2.add(67);
        ArrSet2.add(98);
        ArrSet2.add(100);
 
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet 2: "
                           + ArrSet2);
 
        // compares both using equal() function
        if (ArrSet1.equals(ArrSet2))
            System.out.println("Both are Equal");
        else
            System.out.println("Both are not Equal");
    }
}

输出

CopyOnWriteArraySet 1: [32, 67, 98, 100]
CopyOnWriteArraySet 2: [32, 67, 98, 100]
Both are Equal

程序2

// Java Program to illustrate the
// equals() 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> ArrSet1
            = new CopyOnWriteArraySet<Integer>();
 
        // Add elements
        ArrSet1.add(32);
        ArrSet1.add(67);
        ArrSet1.add(98);
        ArrSet1.add(100);
 
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet 1: "
                           + ArrSet1);
 
        // create object of CopyOnWriteArraySet
        CopyOnWriteArraySet<Integer> ArrSet2
            = new CopyOnWriteArraySet<Integer>();
 
        // Add elements
        ArrSet2.add(3);
        ArrSet2.add(6);
        ArrSet2.add(9);
        ArrSet2.add(10);
 
        // print CopyOnWriteArraySet
        System.out.println("CopyOnWriteArraySet 2: "
                           + ArrSet2);
 
        // compares both using equal() function
        if (ArrSet1.equals(ArrSet2))
            System.out.println("Both are Equal");
        else
            System.out.println("Both are not Equal");
    }
}

输出

CopyOnWriteArraySet 1: [32, 67, 98, 100]
CopyOnWriteArraySet 2: [3, 6, 9, 10]
Both are not Equal

参考资料: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CopyOnWriteArraySet.html#equals-java.lang.Object-