Java LongStream limit() Method

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.