User Interface Process Component

3-Tier architecture generally contains UI or Presentation Layer, Business Access Layer (BAL) or Business Logic Layer and Data Access Layer (DAL).

Presentation Layer (UI)
Presentation layer cotains pages like .aspx or windows form where data is presented to the user or input is taken from the user.

Business Access Layer (BAL) or Business Logic Layer
BAL contains business logic, validations or calculations related with the data, if needed. I will call it Business Access Layer in my demo.

Data Access Layer (DAL)
DAL contains methods that helps business layer to connect the data and perform required action, might be returning data or manipulating data (insert, update, delete etc). For this demo application, I have taken a very simple example. I am assuming that I have to play with record of persons (FirstName, LastName, Age) and I will refer only these data through out this article.


User Interface Process Components

Complex user interfaces often require many highly complex forms. To increase reusability, maintainability, and extensibility, you can create a separate user interface process (UIP) component to encapsulate dependencies between forms and the logic associated with navigating between them. You can apply the same concept to the dependencies, validation, and navigation between components of a single form. These UIP components are typically custom components that are based on design patterns.

The interaction between UI and UIP components often follows the Model-View-Controller or Presentation-Abstraction-Controller.