What is a structure point and what are its characteristics in domain engineering?

Structure points are one of the terms with which most of us are rarely familiar. But, the structure points indeed play an important role in the domain engineering.  Those who know something about the domain engineering, might be familiar with the term. This article is all about the structure points, their characteristics and what role have they got to play in the domain engineering. 

But, before moving on to the structure points, you need to know at least a little about the domain engineering.  

About Domain Engineering

Domain engineering consists of 3 primary phases namely:

1. Domain analysis
2. Domain design
3. Domain implementation

- Firstly, the application domain that is to be investigated is defined and all the common and varying points obtained from the domain are categorized. 

- These common and varying points are represented by the domain model. 

- The representative applications that are the result of the domain analysis are subjected to analyzation based on which the domain model is prepared which serves with the development of the architecture of the software system or application. 

- This process results in the formation of another model called the structural model. 

- This structural is said to consiss of a small number of structural elements in which you can clearly observe the interaction patterns manifesting. 

- The architectural that has been created in the previous steps can be re- used wherever required in the whole domain.

- The structural model is where the structure points come in to play! They act as distinct constructs within the structural model aspects like:

1. Interface
2. Response mechanism
3. Control mechanism etc.

The domain engineering promotes the re- use of the components of the existing software systems or applications. A repository of the re- usable components or artifacts is created.

Now moving on to the characteristics of the structure points, they have got three basic characteristics:

Characteristics of Structure Points

1. The structure points ought to implement the concept of information hiding by the means of isolating all the complexity of them. This has provided a great deal of help in the reduction of the overall perceived complex nature of the software system or application.

2. With the structure points, abstractions having a limited number of instances in the application re- occur in all the applications that lie within a domain. The size of the class hierarchy should be small for this characteristic to take effect. Plus if the abstraction does not occur in all the parts of the software application, you won’t be able to justify the cost to verify, document and disseminate the structure points.

3. The rules that govern the use of structure point are very easy to understand plus the interface of the structure point is relatively very simple.

What is Structural Modeling and what is the role of structure point?

- The structure modelling is an essential approach to the domain engineering and is facilitated by the structure points. 

- Structural modelling is actually a pattern based approach and works up on the assumption that every application domain consists of repeating patterns that can be effectively reused. 

- A structural model is composed of a number of structure points.

- These elements only characterize the architecture of the software systems or applications. 

- Simple patterns of interaction among these structure points can result in the formation of many architectural units. 

- Thus, structure point can be identified as a distinct construct within a structural model. 

Therefore the characterization of the structure points can be done as follows:

1. The number of instances of the structure point should be limited.
2. The interface should be relatively simple.
3. Information hiding must be implemented by the structure point by isolation all the complexity contained within the structure point.