Java DoubleStream forEach() Method

The forEach() method in Java, part of the java.util.stream.DoubleStream interface, is used to perform an action for each element of the stream. This method is useful when you need to apply a specific operation to all elements of a stream, such as printing them or updating a value.

Table of Contents

1. Introduction
2. forEach() Method Syntax
3. Understanding forEach()
4. Examples
   • Basic Usage
   • Using forEach() for Custom Operations
5. Real-World Use Case
6. Conclusion

Introduction

The forEach() method is a terminal operation that performs an action for each element of the stream. This method is particularly useful for iterating over all elements of the stream and applying a specific operation to each element.

forEach() Method Syntax

The syntax for the forEach() method is as follows:

void forEach(DoubleConsumer action)

Parameters:

• action: A DoubleConsumer that represents the action to be performed for each element of the stream.

Returns:

• This method does not return any value.

Throws:

• This method does not throw any exceptions.

Understanding forEach()

The forEach() method allows you to apply a specified action to each element of a DoubleStream. The method takes a DoubleConsumer as an argument, which defines the action to be performed on each element. This method is commonly used for printing elements, updating values, or performing other side effects.

Examples

Basic Usage

To demonstrate the basic usage of forEach(), we will create a DoubleStream and print each element of the stream.

Example

import java.util.stream.DoubleStream;

public class ForEachExample {
    public static void main(String[] args) {
        DoubleStream doubleStream = DoubleStream.of(1.1, 2.2, 3.3, 4.4, 5.5);

        // Print each element of the stream
        doubleStream.forEach(System.out::println);
    }
}

Output:

1.1
2.2
3.3
4.4
5.5

Using forEach() for Custom Operations

This example shows how to use forEach() to apply a custom operation to each element of a DoubleStream. In this case, we will multiply each element by 2 and print the result.

Example

import java.util.stream.DoubleStream;

public class CustomOperationExample {
    public static void main(String[] args) {
        DoubleStream doubleStream = DoubleStream.of(1.1, 2.2, 3.3, 4.4, 5.5);

        // Multiply each element by 2 and print the result
        doubleStream.forEach(n -> System.out.println(n * 2));
    }
}

Output:

2.2
4.4
6.6
8.8
11.0

Real-World Use Case

Updating Sensor Data

In real-world applications, the forEach() method can be used to update sensor data by applying a specific operation to each reading.

Example

import java.util.stream.DoubleStream;

public class SensorDataUpdateExample {
    public static void main(String[] args) {
        DoubleStream sensorData = DoubleStream.of(25.3, 26.7, 24.8, 27.5, 30.1);

        // Apply a calibration factor to each sensor reading and print the updated values
        double calibrationFactor = 1.05;
        sensorData.forEach(reading -> {
            double updatedReading = reading * calibrationFactor;
            System.out.println("Updated reading: " + updatedReading);
        });
    }
}

Output:

Updated reading: 26.565
Updated reading: 28.035
Updated reading: 26.040000000000003
Updated reading: 28.875
Updated reading: 31.605000000000004

Conclusion

The DoubleStream.forEach() method is used to perform an action for each element of the stream. This method is particularly useful for iterating over all elements of the stream and applying a specific operation to each element. By understanding and using this method, you can efficiently manage and manipulate streams of double values in your Java applications.