Java DoubleStream parallel()

DoubleStream parallel() 是 java.util.stream.DoubleStream 中的一个方法。该方法返回一个并行的DoubleStream，也就是说，它可能会返回自己，这是因为流已经存在，或者是因为底层的流状态被修改成了并行。

DoubleStream parallel()是一个 中间操作。 这些操作始终是懒惰的。中间操作是在一个流实例上调用的，在它们完成处理后，会给出一个流实例作为输出:

语法:

DoubleStream parallel()

其中，DoubleStream是一串原始的
元素的序列，并且该函数
返回一个并行的DoubleStream。

例1 :

// Java program to demonstrate working of
// DoubleStream parallel() on a given range
import java.util.*;
import java.util.stream.DoubleStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating a stream of doubles
        DoubleStream stream = 
              DoubleStream.of(5.2, 12.6, 4.5, 7.8);
  
        System.out.println("The corresponding "
                           + "parallel DoubleStream is :");
        stream.parallel().forEach(System.out::println);
    }
}

输出:

The corresponding parallel DoubleStream is :
4.5
7.8
12.6
5.2

例2 :

// Printing sequential stream for the
// same input as above example 1.
import java.util.*;
import java.util.stream.DoubleStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating a stream of doubles
        DoubleStream stream = 
                 DoubleStream.of(5.2, 12.6, 4.5, 7.8);
  
        System.out.println("The corresponding "
                           + "sequential DoubleStream is :");
        stream.sequential().forEach(System.out::println);
    }
}

输出:

The corresponding sequential DoubleStream is :
5.2
12.6
4.5
7.8

例3 :

// Java program to show sorted output
// of parallel stream.
import java.util.*;
import java.util.stream.DoubleStream;
  
class GFG {
  
    // Driver code
    public static void main(String[] args)
    {
        // Creating a stream of doubles
        DoubleStream stream =
                DoubleStream.of(2.3, 3.0, 4.5, 6.6);
  
        System.out.println("The sorted parallel"
                           + " DoubleStream is :");
        stream.parallel().sorted().forEach(System.out::println);
    }
}

输出:

The sorted parallel DoubleStream is :
4.5
6.6
2.3
3.0