The last pattern from this chapter, builder, helps with creating complex objects or their representations. The general idea behind the pattern is to separate such a process into two parts: one gives instructions to an abstract builder interface, and another converts the instructions into a concrete representation. This allows us to create multiple representations from the same construction process.
The builder pattern is similar to an automated coffee/tea machine that always follows the same build process: put a cup on the tray, insert the correct beverage into the system, flow hot water through the system into the cup, and beep at the end. While the build process is always the same, the end result depends on a concrete implementation of step two.
The builder pattern is very similar to the abstract factory pattern. In both cases, the shared class uses an abstract interface...