BUILDER

Question 1

Builder is

Answer 1

a creational design pattern that lets you construct
complex objects step by step. The pattern allows you to produce different types and representations of an object using
the same construction code.

Question 2

The Builder interface declares

Answer 2

product construction steps that
are common to all types ofbuilders.

Question 3

Concrete Builders provide

Answer 3

different implementations of the
construction steps. Concrete builders may produce products
that don’t follow the common interface.

Question 4

Products are

Answer 4

resulting objects. Products constructed by different builders don’t have to belong to the same class hierarchy
or interface.

Question 5

The Director class defines

Answer 5

the order in which to call construction steps, so you can create and reuse specific configurations
of products.

Question 6

What must the client associate with the director?

Answer 6

The client must associate one of the builder objects with the director

Question 7

How is the builder usually associated with the director?

Answer 7

It’s usually done once, via the parameters of the director’s constructor.

Question 8

What does the director do after associating the builder?

Answer 8

The director uses that builder object for all further construction.

Question 9

Is there an alternative approach for associating the builder with the director?

Answer 9

Yes, the client can pass the builder object to the production method of the director.

Question 10

What is the benefit of passing a builder object to the director’s production method?

Answer 10

In this case, you can use a different builder each time you produce something with the director.

Question 11

What problem does the Builder pattern solve in constructors?

Answer 11

It helps avoid a “telescopic constructor” where constructors with many optional parameters are overloaded.

Question 12

What is a telescopic constructor?

Answer 12

It is a constructor with many optional parameters, often overloaded to provide shorter versions with fewer parameters.

Question 13

What does the Builder pattern allow developers to do?

Answer 13

It allows developers to build objects step by step, using only the steps they need, without cramming dozens of parameters into constructors.

Question 14

When is the Builder pattern useful?

Answer 14

It’s useful when you need to create different representations of a product that involve similar steps, differing only in the details.

Question 15

What does the base builder interface define?

Answer 15

The base builder interface defines all possible construction steps.

Question 16

What do concrete builders do?

Answer 16

Concrete builders implement the construction steps to build specific representations of the product.

Question 17

What role does the director class play in the Builder pattern?

Answer 17

The director class guides the order of construction and can use the same builder object in various ways to construct the product.

Question 18

What is the benefit of using the Builder pattern for complex objects?

Answer 18

It allows for constructing complex objects, such as composite trees, step by step, and you can defer or run some steps recursively.

Question 19

What is one important consideration when implementing the Builder pattern?

Answer 19

You need to ensure that the common construction steps for all product representations are clearly defined.

Question 20

What method do builders need to implement?

Answer 20

Builders need to implement a method for fetching the result of construction. This method may differ across builders depending on the product type.

Question 21

How does the Builder pattern relate to the Director class?

Answer 21

The director class can encapsulate various ways of constructing a product using the same builder object, and it can either pass the builder through the constructor or directly to the construction method.

Question 22

When should the client fetch the result of construction?

Answer 22

The client should fetch the result from the builder if the products don’t share a common interface; otherwise, the result can be fetched from the director.

Question 23

What are the main advantages of using the Builder pattern?

Answer 23

It allows step-by-step construction, deferring steps, running steps recursively, reusing construction code for different product representations, and isolating complex construction logic from business logic.

Question 24

What is the downside of using the Builder pattern?

Answer 24

The overall complexity of the code increases due to the need for creating multiple new classes.

Question 25

How does Builder relate to other design patterns?

Answer 25

Builder can evolve from Factory Method and can be combined with Abstract Factory, Prototype, and Bridge. It focuses on building complex objects step by step, while Abstract Factory focuses on creating families of related objects.

Question 26

Can Builder be used with Singleton?

Answer 26

Yes, Abstract Factories, Builders, and Prototypes can all be implemented as Singletons.