Java LongStream limit() Method

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The limit() method in Java, part of the java.util.stream.LongStream interface, is used to truncate the stream to contain no more than a specified number of elements. This method is useful when you need to restrict the size of the stream to a specific number of elements.

Table of Contents

1. Introduction
2. limit() Method Syntax
3. Understanding limit()
4. Examples
   • Basic Usage
   • Using limit() with Other Stream Operations
5. Real-World Use Case
6. Conclusion

Introduction

The limit() method returns a stream consisting of the elements of the original stream, truncated to be no longer than the specified length. This method is an intermediate operation, meaning it returns a new stream and does not modify the original stream.

limit() Method Syntax

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

LongStream limit(long maxSize) 

Parameters:

• maxSize: The number of elements the resulting stream should be limited to.

Returns:

• A new LongStream consisting of the elements of the original stream, truncated to the specified length.

Throws:

• IllegalArgumentException if maxSize is negative.

Understanding limit()

The limit() method allows you to restrict the number of elements in a stream. It is useful for scenarios where you need to process only a specific number of elements from a potentially large stream.

Examples

Basic Usage

To demonstrate the basic usage of limit(), we will create a LongStream and use limit() to truncate it to a specific number of elements.

Example

import java.util.stream.LongStream; public class LimitExample { public static void main(String[] args) { LongStream stream = LongStream.of(1L, 2L, 3L, 4L, 5L); // Use limit() to truncate the stream to 3 elements LongStream limitedStream = stream.limit(3); // Print the elements of the limited stream limitedStream.forEach(System.out::println); } } 

Output:

1 2 3 

Using limit() with Other Stream Operations

This example shows how to use limit() in combination with other stream operations, such as filtering.

Example

import java.util.stream.LongStream; public class LimitWithFilterExample { public static void main(String[] args) { LongStream stream = LongStream.of(10L, 20L, 30L, 40L, 50L); // Use limit() to truncate the stream to 2 elements after filtering LongStream limitedStream = stream.filter(n -> n > 20).limit(2); // Print the elements of the limited stream limitedStream.forEach(System.out::println); } } 

Output:

30 40 

Real-World Use Case

Limiting the Number of Processed Transactions

In real-world applications, the limit() method can be used to limit the number of processed transactions from a stream of transaction values.

Example

import java.util.stream.LongStream; public class LimitTransactionsExample { public static void main(String[] args) { LongStream transactionAmounts = LongStream.of(1000L, 2000L, 1500L, 3000L, 2500L); // Use limit() to process only the first 3 transactions LongStream limitedTransactions = transactionAmounts.limit(3); // Print the limited transaction amounts limitedTransactions.forEach(amount -> System.out.println("Transaction Amount: " + amount)); } } 

Output:

Transaction Amount: 1000 Transaction Amount: 2000 Transaction Amount: 1500 

Conclusion

The LongStream.limit() method is used to truncate the stream to contain no more than a specified number of elements. This method is particularly useful for restricting the size of the stream to a specific number of elements. By understanding and using this method, you can efficiently manage and process streams of values in your Java applications, ensuring that only a limited number of elements are processed as needed.