Working with Pairs in Java

In many scenarios, we often need to work with pairs of values. Java doesn’t provide a built-in class for representing pairs, but we can create our own or leverage libraries that offer this functionality. In this article, we’ll explore different approaches to working with pairs in Java.

Option 1: Creating a Pair Class

One way to work with pairs in Java is by creating our own Pair class. This class will encapsulate two values and provide methods for accessing and manipulating them.

Here’s an example implementation of a Pair class:

public class Pair<F, S> {
    private F first;
    private S second;

    public Pair(F first, S second) {
        this.first = first;
        this.second = second;
    }

    public F getFirst() {
        return first;
    }

    public S getSecond() {
        return second;
    }

    public void setFirst(F first) {
        this.first = first;
    }

    public void setSecond(S second) {
        this.second = second;
    }
}

With this Pair class, we can create instances representing pairs of values:

Pair<String, Integer> pair = new Pair<>("Baeldung", 2023);
System.out.println(pair.getFirst()); // Baeldung
System.out.println(pair.getSecond()); // 2023

By creating a custom Pair class, we have a flexible and reusable solution for working with pairs of values in Java.

Option 2: Using Libraries

Instead of creating our own Pair class, we can leverage existing libraries that provide implementations for working with pairs. One popular library is Apache Commons Lang, which offers a Pair class in its org.apache.commons.lang3.tuple package.

Here’s an example of using the Pair class from Apache Commons Lang:

import org.apache.commons.lang3.tuple.Pair;

Pair<String, Integer> pair = Pair.of("Baeldung", 2023);
System.out.println(pair.getLeft()); // Baeldung
System.out.println(pair.getRight()); // 2023

By using libraries like Apache Commons Lang, we can avoid reinventing the wheel and benefit from well-tested and widely adopted solutions for working with pairs.

Conclusion

Working with pairs of values is a common requirement in many Java applications. Although Java doesn’t provide a built-in Pair class, we have different options to work with pairs effectively.

One approach is to create our own Pair class, which allows us to have full control over the implementation and customize it according to our specific needs.

Alternatively, we can use libraries like Apache Commons Lang that offer ready-to-use Pair classes. These libraries provide robust and feature-rich implementations, saving us time and effort.

Choose the approach that best fits your use case and coding style. Whether you create your own Pair class or utilize existing libraries, working with pairs in Java becomes simpler and more expressive.

Happy coding with pairs in Java!