Java DoubleStream concat() Method

The concat() method in Java, part of the java.util.stream.DoubleStream interface, is used to concatenate two DoubleStream instances. This method is useful when you need to combine two streams of double values into a single stream.

Table of Contents

1. Introduction
2. concat() Method Syntax
3. Understanding concat()
4. Examples
   • Basic Usage
   • Using concat() with Multiple Streams
5. Real-World Use Case
6. Conclusion

Introduction

The concat() method returns a concatenated DoubleStream that is a combination of the elements from two given DoubleStream instances. The resulting stream contains all elements of the first stream followed by all elements of the second stream.

concat() Method Syntax

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

public static DoubleStream concat(DoubleStream a, DoubleStream b)

Parameters:

• a: The first DoubleStream.
• b: The second DoubleStream.

Returns:

• A DoubleStream that contains all elements of the first stream followed by all elements of the second stream.

Throws:

• This method does not throw any exceptions.

Understanding concat()

The concat() method allows you to combine two DoubleStream instances into a single stream. This is useful for merging streams of data, such as combining results from different sources or appending additional data to an existing stream.

Examples

Basic Usage

To demonstrate the basic usage of concat(), we will create two DoubleStream instances and concatenate them into a single stream.

Example

import java.util.stream.DoubleStream;

public class ConcatExample {
    public static void main(String[] args) {
        DoubleStream stream1 = DoubleStream.of(1.1, 2.2, 3.3);
        DoubleStream stream2 = DoubleStream.of(4.4, 5.5, 6.6);

        // Concatenate the two streams
        DoubleStream concatenatedStream = DoubleStream.concat(stream1, stream2);

        // Print the concatenated stream
        concatenatedStream.forEach(System.out::println);
    }
}

Output:

1.1
2.2
3.3
4.4
5.5
6.6

Using concat() with Multiple Streams

This example shows how to concatenate multiple DoubleStream instances by chaining concat() calls.

Example

import java.util.stream.DoubleStream;

public class ConcatMultipleStreamsExample {
    public static void main(String[] args) {
        DoubleStream stream1 = DoubleStream.of(1.1, 2.2, 3.3);
        DoubleStream stream2 = DoubleStream.of(4.4, 5.5, 6.6);
        DoubleStream stream3 = DoubleStream.of(7.7, 8.8, 9.9);

        // Concatenate the three streams
        DoubleStream concatenatedStream = DoubleStream.concat(
            DoubleStream.concat(stream1, stream2),
            stream3
        );

        // Print the concatenated stream
        concatenatedStream.forEach(System.out::println);
    }
}

Output:

1.1
2.2
3.3
4.4
5.5
6.6
7.7
8.8
9.9

Real-World Use Case

Combining Data from Multiple Sensors

In real-world applications, the concat() method can be used to combine data from multiple sensors into a single stream for processing.

Example

import java.util.stream.DoubleStream;

public class SensorDataConcatExample {
    public static void main(String[] args) {
        DoubleStream sensor1Data = DoubleStream.of(25.3, 26.7, 24.8);
        DoubleStream sensor2Data = DoubleStream.of(23.1, 27.5, 26.0);
        DoubleStream sensor3Data = DoubleStream.of(25.6, 24.9, 27.3);

        // Concatenate the sensor data streams
        DoubleStream allSensorData = DoubleStream.concat(
            DoubleStream.concat(sensor1Data, sensor2Data),
            sensor3Data
        );

        // Print the combined sensor data stream
        allSensorData.forEach(System.out::println);
    }
}

Output:

25.3
26.7
24.8
23.1
27.5
26.0
25.6
24.9
27.3

Conclusion

The DoubleStream.concat() method is used to concatenate two DoubleStream instances into a single stream. This method is particularly useful for merging streams of double values, allowing you to combine data from multiple sources or append additional data to an existing stream. By understanding and using this method, you can efficiently manage and manipulate streams of double values in your Java applications.