Consider Builder When Faced With Many Constructor Parameters

The common way when you faced with common constuctor params is to define multi constructors or setter and getters methods (JavaBeans).

While there a better way, we will descuss disadvantage of using these common way first.

Disadvantage of Multi Constructors:

Constructor pattern works, but it’s hard to write client code when there are many parameters, and harder still to read it.

Disadvantage of JavaBean:

  • Because construction is split across multiple calls, **A JavaBean may be in and inconsistent state partway through its construction.

  • Precludes the possibility of making class immutable

Advantage of Builder Pattern:

  • Easy to write and more importantly, easy to read.
  • It’s simulates named optional parameters as found in Python and Scala.
  • Well suited to class hierarchies

Builder pattern is good choice when designing classes whose constructors or static factories would have more than a handful of parameters

See Video from my playlist.

See Examples.

Written on July 17, 2019