builder

Bulder pattern

When to use

We use Builder pattern when:

• Too many constructor arguments(i.e. more than three).
• The constructor overloading can lead to incorrect object state.
• We need of flexible API.
• We want to add new parameters to a constructor without producing error-prone and hard to read code.

Real word API examples

Java API

Calendar cal = new Calendar.Builder()
            .setCalendarType("iso8601")
            .setWeekDate(2013, 1, MONDAY)
            .build();

Locale loc = new Builder()
            .setLanguage("sr")
            .setScript("Latn")
            .setRegion("RS")
            .build();