Java DoubleStream noneMatch() Method

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The noneMatch() method in Java, part of the java.util.stream.DoubleStream interface, is used to check if no elements of the stream match a given predicate. This method is useful when you need to verify that none of the elements in a stream satisfy a specific condition.

Table of Contents

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

Introduction

The noneMatch() method returns true if no elements of the stream match the provided predicate. If at least one element matches the predicate, the method returns false. This is a terminal operation and it short-circuits as soon as the result is determined.

noneMatch() Method Syntax

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

boolean noneMatch(DoublePredicate predicate)

Parameters:

• predicate: A DoublePredicate that represents the condition to be checked against the elements of the stream.

Returns:

• true if no elements match the predicate; otherwise, false.

Throws:

• This method does not throw any exceptions.

Understanding noneMatch()

The noneMatch() method allows you to check if no elements in a DoubleStream satisfy a given condition. If the stream is empty, it returns true, as there are no elements to violate the predicate.

Examples

Basic Usage

To demonstrate the basic usage of noneMatch(), we will create a DoubleStream and check if none of the elements are greater than 5.0.

Example

import java.util.stream.DoubleStream;

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

        // Check if no elements are greater than 5.0
        boolean noneGreaterThanFive = doubleStream.noneMatch(n -> n > 5.0);

        System.out.println("None elements greater than 5.0: " + noneGreaterThanFive);
    }
}

Output:

None elements greater than 5.0: true

Using noneMatch() with Custom Predicate

This example shows how to use noneMatch() with a custom predicate to check if none of the elements in a DoubleStream are negative.

Example

import java.util.stream.DoubleStream;

public class CustomPredicateExample {
    public static void main(String[] args) {
        DoubleStream doubleStream = DoubleStream.of(1.0, 2.0, 3.0, 4.0);

        // Check if none of the elements are negative
        boolean noneNegative = doubleStream.noneMatch(n -> n < 0);

        System.out.println("None elements are negative: " + noneNegative);
    }
}

Output:

None elements are negative: true

Real-World Use Case

Checking for Abnormal Temperature Readings

In real-world applications, the noneMatch() method can be used to check if none of the temperature readings are outside a safe range.

Example

import java.util.stream.DoubleStream;

public class TemperatureCheckExample {
    public static void main(String[] args) {
        DoubleStream temperatures = DoubleStream.of(36.5, 37.0, 36.8, 37.1, 36.9);

        // Check if none of the temperatures are outside the safe range (36.5 to 37.5 degrees Celsius)
        boolean allSafe = temperatures.noneMatch(temp -> temp < 36.5 || temp > 37.5);

        System.out.println("All temperatures are within the safe range: " + allSafe);
    }
}

Output:

All temperatures are within the safe range: true

Conclusion

The DoubleStream.noneMatch() method is used to check if no elements of the stream match a given predicate. This method is particularly useful for verifying that none of the elements in a stream satisfy a specific condition. By understanding and using this method, you can efficiently perform validation checks on streams of double values in your Java applications.