Builder
Separates the construction of a complex object from its representation, allowing the same construction process to produce different results.
errorWhat Problem Does the Builder Pattern Solve?
Complex objects with many optional parameters lead to telescoping constructors or massive configuration objects. The construction order may matter, intermediate states can be invalid, and the client is forced to understand every detail of the object’s internals.
check_circleHow the Builder Pattern Works
Extract the construction logic into a separate Builder class that exposes fluent, step-by-step methods. An optional Director can orchestrate common build sequences. The client calls only the steps it needs, and the builder assembles a valid, immutable product at the end.
Builder Pattern Architecture
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Implementation by Language
Builder Pattern in the Real World
“Consider ordering a custom sandwich at a deli. You tell the sandwich artist (builder) each step — bread type, protein, toppings, sauce — and they assemble it in the right order. You don’t need to know how to layer ingredients properly; you just specify what you want, and the builder hands you a finished sandwich.”
Frequently Asked Questions
helpWhat is the difference between Builder and Factory patterns?
Factory patterns create objects in a single step — you call a method and get a complete object. Builder constructs objects step-by-step, allowing you to configure each part independently. Use Builder when objects have many optional parameters or require complex assembly sequences.
helpShould Builder always have a Director class?
No. The Director is optional and useful when you have predefined construction sequences you want to reuse. In modern code, fluent builders (method chaining) often replace the Director pattern entirely, as the client code itself orchestrates the build steps.