From Constructor Overload Chaos to the Builder Pattern: Designing Travel Packages the Right Way

When classes start offering too many ways to be created, developers often overload constructors:

• TravelPackage(string destination)

• TravelPackage(string destination, DateTime startDate)

• TravelPackage(string destination, DateTime startDate, int nights)

• TravelPackage(string destination, DateTime startDate, int nights, bool includeMeals, bool includeGuide, bool airportPickup)

👉 This gets messy fast. You end up with “constructor explosion”: hard-to-read code, endless overloads, and parameters that are easy to misplace.

Enter the Builder Pattern.

Real-World Example: Travel Packages

Imagine a travel agency system where customers can book customized travel packages. A package may include:

• Destination

• Travel dates

• Number of nights

• Meals included or not

• Local guide

• Airport pickup

Problem: Multiple Constructors

public class TravelPackage
{
    public string Destination { get; }
    public DateTime StartDate { get; }
    public int Nights { get; }
    public bool MealsIncluded { get; }
    public bool GuideIncluded { get; }
    public bool AirportPickup { get; }

    // Too many constructors!
    public TravelPackage(string destination) { ... }
    public TravelPackage(string destination, DateTime startDate) { ... }
    public TravelPackage(string destination, DateTime startDate, int nights) { ... }
    public TravelPackage(string destination, DateTime startDate, int nights, bool meals, bool guide, bool pickup) { ... }
}

Problems:

• Hard to remember which overload to use.

• Boolean parameters (true, false, true) make the code unreadable.

• Adding a new option forces new constructors → code bloat.

Solution: The Builder Pattern

The Builder Pattern solves this by allowing step-by-step object construction with a fluent API.

Step 1: Define the Class with a Private Constructor

public class TravelPackage
{
    public string Destination { get; private set; }
    public DateTime StartDate { get; private set; }
    public int Nights { get; private set; }
    public bool MealsIncluded { get; private set; }
    public bool GuideIncluded { get; private set; }
    public bool AirportPickup { get; private set; }

    private TravelPackage() { } // force creation via Builder

    public override string ToString()
    {
        return $"{Destination}, {Nights} nights starting {StartDate:d} | " +
               $"Meals: {MealsIncluded}, Guide: {GuideIncluded}, Pickup: {AirportPickup}";
    }

    // Nested Builder Class
    public class Builder
    {
        private readonly TravelPackage _package = new TravelPackage();

        public Builder To(string destination)
        {
            _package.Destination = destination;
            return this;
        }

        public Builder StartingOn(DateTime startDate)
        {
            _package.StartDate = startDate;
            return this;
        }

        public Builder StayingFor(int nights)
        {
            _package.Nights = nights;
            return this;
        }

        public Builder WithMeals(bool include = true)
        {
            _package.MealsIncluded = include;
            return this;
        }

        public Builder WithGuide(bool include = true)
        {
            _package.GuideIncluded = include;
            return this;
        }

        public Builder WithPickup(bool include = true)
        {
            _package.AirportPickup = include;
            return this;
        }

        public TravelPackage Build() => _package;
    }
}

Step 2: Build a Package Step by Step

var baliTrip = new TravelPackage.Builder()
    .To("Bali")
    .StartingOn(new DateTime(2025, 12, 1))
    .StayingFor(7)
    .WithMeals()
    .WithGuide()
    .WithPickup()
    .Build();

Console.WriteLine(baliTrip);

Output:

Bali, 7 nights starting 12/1/2025 | Meals: True, Guide: True, Pickup: True

What is a Fluent API?

The Builder Pattern often uses a Fluent API style — that’s why it looks so readable. But what does “fluent” actually mean?

A Fluent API is simply a way of designing methods so that they return the same object (this), allowing method calls to be chained together in a single, readable line.

👉 Instead of writing:

var package = new TravelPackage.Builder();
package.To("Bali");
package.StartingOn(new DateTime(2025, 12, 1));
package.StayingFor(7);
package.WithMeals();
package.Build();

You can write:

var package = new TravelPackage.Builder()
    .To("Bali")
    .StartingOn(new DateTime(2025, 12, 1))
    .StayingFor(7)
    .WithMeals()
    .Build();

How Fluent API Works in the Builder

Look at one method in our TravelPackage.Builder:

public Builder To(string destination)
{
    _package.Destination = destination;
    return this; // ✅ enables chaining
}

• Returning this means the next method in the chain can be called on the same builder object.

• Every method updates part of the object, then hands control back to you.

Why Builder Wins

• Readability: The code is almost self-describing (WithMeals(), WithPickup()), unlike random true/false flags.

• Flexibility: You can add new features (WithInsurance()) without breaking existing code.

• Maintainability: No constructor overload explosion.

• Optional parameters: Only set what matters; others stay at defaults.

Key Takeaway

• Constructor Overloading works for simple classes with 2–3 variations.

• As options grow, it leads to constructor explosion and unreadable code.

• The Builder Pattern is the elegant solution: it gives a fluent, readable, and scalable way to create objects.