Rules of thumb
Sometimes creational patterns are competitors: there are cases when
either Prototype or Abstract Factory could be used
profitably. At other times they are complementory: Abstract
Factory might store a set of Prototypes from which to clone
and return product objects [GOF, p126], Builder can use one of
the other patterns to implement which components get built.
Abstract Factory, Builder, and Prototype can use
Singleton in their implementation. [GOF, pp81,134]
Abstract Factory, Builder, and Prototype define a
factory object that's responsible for knowing and creating the class of
product objects, and make it a parameter of the system. Abstract
Factory has the factory object producing objects of several
classes. Builder has the factory object building a complex
product incrementally using a correspondingly complex protocol.
Prototype has the factory object (aka prototype) building a
product by copying a prototype object. [GOF, p135]
Abstract Factory classes are often implemented with Factory
Methods, but they can also be implemented using Prototype.
Abstract Factory can be used as an alternative to Facade
to hide platform-specific classes. [GOF, p193]
Builder focuses on constructing a complex object step by step.
Abstract Factory emphasizes a family of product objects (either
simple or complex). Builder returns the product as a final
step, but as far as the Abstract Factory is concerned, the
product gets returned immediately. [GOF, p105]
Builder is to creation as Strategy is to algorithm.
Builder often builds a Composite. [GOF, p106]
Factory Methods are usually called within Template
Methods. [GOF, p116]
Factory Method: creation through inheritance. Prototype:
creation through delegation.
Often, designs start out using Factory Method (less complicated,
more customizable, subclasses proliferate) and evolve toward
Abstract Factory, Prototype, or Builder (more
flexible, more complex) as the designer discovers where more
flexibility is needed. [GOF, p136]
Prototype doesn't require subclassing, but it does require an
Initialize operation. Factory Method requires subclassing,
but doesn't require Initialize. [GOF, p116]
Designs that make heavy use of the Composite and Decorator
patterns often can benefit from Prototype as well. [GOF, p126]