OptionalDouble stream() method in Java with examples

The stream() method help us to get double value contain by OptionalDouble as DoubleStream.If a value is present, method returns a sequential DoubleStream containing only that value, otherwise returns an empty DoubleStream.

Syntax:

public DoubleStream stream()

Parameters: This method accepts nothing.

Return value: This method returns the optional value as an DoubleStream.

Below programs illustrate stream() method:
Program 1:

// Java program to demonstrate
// OptionalDouble.stream() method

import java.util.OptionalDouble;
import java.util.stream.DoubleStream;

public class GFG {

    public static void main(String[] args)
    {

        // create a OptionalDouble
        OptionalDouble opDouble
            = OptionalDouble.of(.3203);

        // get value as stream
        DoubleStream out = opDouble.stream();

        // print value
        System.out.print("Value: ");
        out.forEach(System.out::print);
    }
}

Output:

Program 2:

// Java program to demonstrate
// OptionalDouble.stream() method

import java.util.OptionalDouble;
import java.util.stream.DoubleStream;

public class GFG {

    public static void main(String[] args)
    {

        // create a empty OptionalDouble
        OptionalDouble opDouble
            = OptionalDouble.empty();

        // get value as stream
        DoubleStream out = opDouble.stream();

        // print value
        System.out.print("length of Double Stream: "
                         + out.count());
    }
}

Output:

References: https://docs.oracle.com/javase/10/docs/api/java/util/OptionalDouble.html#empty()