The builder pattern serves the same purpose as the other creational patterns, but it does so in a different way and for different reasons. When developing complex applications, the code tends to become more complex. Classes tend to encapsulate more functionality and, at the same time, class structures become more complex. As the functionality grows, more scenarios need to be covered and, for these, different representations of classes are required.
When we have a complex class that we need to instantiate to different objects with different structures or different internal states, we can use separate classes to encapsulate the instantiation logic. These classes are called builders. Each time we need objects from the same class with a different structure, we can create another builder to create such instances.
The same concept can be used not only for classes for which we need different representations but also for complex objects composed of other objects.
Creating builder classes...