Java中的 BitSet stream() 方法及示例

Java BitSet 类的 stream() 方法用于返回 BitSet 中包含的每个位的索引流。索引按升序返回。流的大小是 BitSet 的设置状态的位数，等于 cardinality() 方法返回的值。

句法：

public IntStream stream()

参数：该方法不带任何参数。
返回值：该方法为 BitSet 中包含的每个位返回一个索引流。

下面的程序说明了Java.util.BitSet.stream() 方法的工作：
方案一：

// Java code to illustrate stream()
import java.util.*;
import java.util.stream.IntStream;
  
public class BitSet_Demo {
    public static void main(String args[])
    {
        // Creating an empty BitSet
        BitSet init_bitset = new BitSet();
  
        // Use set() method to add elements into the Set
        init_bitset.set(10);
        init_bitset.set(20);
        init_bitset.set(30);
        init_bitset.set(40);
        init_bitset.set(50);
  
        // Displaying the BitSet
        System.out.println("BitSet: " + init_bitset);
  
        // Creating an IntStream
        IntStream indice_Stream = init_bitset.stream();
  
        // Displaying the working
        System.out.println("The BitSet: " + init_bitset);
        System.out.println("The stream of indices: "
                           + indice_Stream);
        System.out.println("The size of the stream: "
                           + indice_Stream.count());
    }
}

输出：

BitSet: {10, 20, 30, 40, 50}
The BitSet: {10, 20, 30, 40, 50}
The stream of indices: java.util.stream.IntPipeline$Head@4eec7777
The size of the stream: 5

方案二：

// Java code to illustrate stream()
import java.util.*;
import java.util.stream.IntStream;
  
public class BitSet_Demo {
    public static void main(String args[])
    {
        // Creating an empty BitSet
        BitSet init_bitset = new BitSet();
  
        // Use set() method to add elements into the Set
        init_bitset.set(40);
        init_bitset.set(25);
        init_bitset.set(31);
        init_bitset.set(100);
        init_bitset.set(121);
        init_bitset.set(400);
        init_bitset.set(2);
        init_bitset.set(15);
        init_bitset.set(106);
        init_bitset.set(55);
  
        // Displaying the BitSet
        System.out.println("BitSet: " + init_bitset);
  
        // Creating an IntStream
        IntStream indice_Stream = init_bitset.stream();
  
        // Displaying the working
        System.out.println("The BitSet: " + init_bitset);
        System.out.println("The stream of indices: "
                           + indice_Stream);
        System.out.println("The size of the stream: "
                           + indice_Stream.count());
    }
}

输出：

BitSet: {2, 15, 25, 31, 40, 55, 100, 106, 121, 400}
The BitSet: {2, 15, 25, 31, 40, 55, 100, 106, 121, 400}
The stream of indices: java.util.stream.IntPipeline$Head@4eec7777
The size of the stream: 10