condition based lombok building of objects

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06-10-2024

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Building Objects with Lombok: A Conditional Approach

Have you ever found yourself writing repetitive, boilerplate code for object creation? Maybe you're constantly setting default values, conditionally constructing objects based on specific parameters, or struggling to manage complex object dependencies. If so, Lombok can be your lifesaver. This powerful library simplifies Java development by automating tedious tasks, allowing you to focus on the core logic of your application.

But what if you need to build objects with conditional logic, choosing specific fields based on different conditions? This is where Lombok's power truly shines.

Scenario: Building a User Object with Conditional Fields

Imagine you're building a user management system. You have a User class with fields like firstName, lastName, email, phoneNumber, and address. However, you only want to include certain fields based on user type:

• Basic User: Only firstName, lastName, and email are required.
• Premium User: Additionally needs phoneNumber.
• VIP User: Includes address on top of the Premium User fields.

Here's how you might do it without Lombok:

public class User {
  private String firstName;
  private String lastName;
  private String email;
  private String phoneNumber;
  private String address;

  public User(String firstName, String lastName, String email) {
    this.firstName = firstName;
    this.lastName = lastName;
    this.email = email;
  }

  public User(String firstName, String lastName, String email, String phoneNumber) {
    this(firstName, lastName, email);
    this.phoneNumber = phoneNumber;
  }

  public User(String firstName, String lastName, String email, String phoneNumber, String address) {
    this(firstName, lastName, email, phoneNumber);
    this.address = address;
  }

  // Getters and setters...
}

This approach requires multiple constructors, leading to cumbersome code and potential for errors.

Enter Lombok: Simplifying Conditional Object Creation

Lombok provides a powerful solution with its @Builder annotation. By using it, we can create a builder class for our User object, allowing us to conditionally add fields:

import lombok.Builder;
import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
@Builder
public class User {
  private String firstName;
  private String lastName;
  private String email;
  private String phoneNumber;
  private String address;
}

Now, we can build our user object with conditional logic:

User basicUser = User.builder()
    .firstName("John")
    .lastName("Doe")
    .email("[email protected]")
    .build();

User premiumUser = User.builder()
    .firstName("Jane")
    .lastName("Smith")
    .email("[email protected]")
    .phoneNumber("555-123-4567")
    .build();

User vipUser = User.builder()
    .firstName("Peter")
    .lastName("Brown")
    .email("[email protected]")
    .phoneNumber("555-987-6543")
    .address("123 Main Street")
    .build();

Benefits of using Lombok for Conditional Building

• Reduced Boilerplate: No need to write multiple constructors.
• Improved Readability: Code is more concise and easier to understand.
• Increased Flexibility: Easily modify the fields included in the builder based on conditions.
• Immutability: The builder pattern promotes immutability, making your code more robust.

Further Enhancing Conditional Logic

You can further customize your conditional building process:

• Default Values: Use the @Builder.Default annotation to specify default values for fields.
• Required Fields: Use the @Builder.RequiredArgsConstructor annotation to enforce required fields.
• Nested Builders: Build nested objects within the User builder for complex relationships.

By using Lombok's @Builder annotation in combination with conditional logic, you can significantly streamline your object creation process, resulting in cleaner, more maintainable, and efficient code.

Remember: Leverage the power of Lombok to automate tedious tasks and focus on the core logic of your application.