The limit()
method in Java is a part of the java.util.stream.Stream
interface. In this guide, we will learn how to use limit()
method in Java with practical examples and real-world use cases to better understand its usage.
Table of Contents
- Introduction
limit()
Method Syntax- Understanding
limit()
- Examples
- Basic Usage
- Using
limit()
with Filtered Streams
- Real-World Use Case
- Conclusion
Introduction
The Stream.limit()
method in Java is used to limit the number of elements in a stream. It returns a stream with a specified maximum number of elements.
This method is helpful when you only need a subset of the stream’s elements, especially for large or infinite streams.
limit()
is commonly used with operations like generate()
or filter()
to control the size of the processed data.
limit() Method Syntax
The syntax for the limit()
method is as follows:
Stream<T> limit(long maxSize)
Parameters:
maxSize
: The number of elements the resulting stream should be limited to.
Returns:
- A new
Stream
consisting of the elements of the original stream, truncated to the specified length.
Throws:
IllegalArgumentException
: IfmaxSize
is negative.
Understanding limit() in Simple Words
The limit()
method allows you to limit the number of elements in a stream to a specified maximum size. This is particularly useful when you only need to process a subset of the elements in a stream.
Examples
Basic Usage
To demonstrate the basic usage of limit()
, we will create a Stream
and use limit()
to truncate it to a specific number of elements.
Example
import java.util.stream.Stream;
public class LimitExample {
public static void main(String[] args) {
Stream<String> stream = Stream.of("apple", "banana", "cherry", "date", "elderberry");
// Use limit() to truncate the stream to 3 elements
Stream<String> limitedStream = stream.limit(3);
// Print the limited elements
limitedStream.forEach(System.out::println);
}
}
Output:
apple
banana
cherry
Using limit()
with Filtered Streams
This example shows how to use limit()
in combination with other stream operations, such as filtering.
Example
import java.util.stream.Stream;
public class LimitWithFilterExample {
public static void main(String[] args) {
Stream<String> stream = Stream.of("apple", "banana", "cherry", "date", "elderberry");
// Filter elements that start with 'a' or 'b', and limit the result to 2 elements
Stream<String> limitedStream = stream.filter(s -> s.startsWith("a") || s.startsWith("b"))
.limit(2);
// Print the limited elements
limitedStream.forEach(System.out::println);
}
}
Output:
apple
banana
Real-World Use Case
Pagination
In real-world applications, the limit()
method can be used to implement pagination by combining it with skip()
to process specific pages of data.
Example
import java.util.stream.Stream;
public class PaginationExample {
public static void main(String[] args) {
Stream<String> stream = Stream.of("apple", "banana", "cherry", "date", "elderberry",
"fig", "grape", "honeydew");
int page = 2;
int pageSize = 3;
// Use skip() to skip the elements of previous pages, and limit() to get the elements of the current page
Stream<String> pageStream = stream.skip((page - 1) * pageSize)
.limit(pageSize);
// Print the elements of the current page
pageStream.forEach(System.out::println);
}
}
Output:
date
elderberry
fig
Conclusion
The Stream.limit()
method is used to truncate a stream to a specified maximum length. This method is particularly useful for scenarios where you need to process only a specific number of elements from a stream.
By understanding and using this method, you can efficiently manage and process streams of values in your Java applications, ensuring that you work with only the required number of elements.