Builder pattern

Intend

The builder pattern is to separate the construction of a complex object from its representation, allowing for a step-by-step construction process.

It suggests that you extract the object construction code out of its own class and move it to separate objects called builders.

Builder pattern often uses a fluent interface, which facilitates method chaining.

Method Chaining: By returning the Builder instance, you can chain multiple method calls together in a single, fluent expression. This makes the code more readable and concise.

Key points to consider when creating a builder pattern:

• The main class (Phone) constructor should be private because object construction is managed only by the Builder class.

• The private constructor should accept only a Builder class instance, which initializes the values of the main class attributes.

• The main class should not provide any setter methods; it should contain only getter methods to create an immutable object.

• The Builder class should be static.

• All the Builder class methods should return the Builder instance (fluent interface).

• Finally, the build method should return the fully constructed object of the main class, not the Builder instance

Examples where the builder pattern is used in Java

• StringBuilder and StringBuffer

• java.nio.file.Path and java.nio.file.Paths

• Stream.Builder

• LocalDateTime, LocalDate and LocalTime