Classification of Design Patterns - Assignment Example

?Design patterns Number: Lecturer: In the system that is being created, there will be the creation and the use of design patterns. With the need to have a web-based information system, there will be the use of design patterns when undertaking the project. Because there are various objects that will be involved in the new Alpha Numeric Data Company (ANDC) system. The reason for this is that there will be various objects and the working of these objects will be behind the scenes. This paper will focus on the design patterns that will be used in ANDC. Name of design pattern: Data access object Classification: Design Problem: The problem that will be got is that the users will be exposed to complex working and operation of the program. This should not be the case as the users should only access simple interface without any much complications of the system. Solution: The solution that will be applied in the system is the use of DAO pattern. In the system, the use cases who will be involved include making an online purchase, making an online inquiry, and making payment. The use case diagram below show the use cases which will need the use of this design pattern in our case. Consequences The first design pattern that will be used is that of the data access object. Data access object is a design pattern that is used to hide the complexity of the program for the user. Users are not supposed to get the details of how the program has been developed. This is where the data access object comes in. The DAO helps data access mechanisms to be able to change without depending on the code that makes use of the data. It is tasked with the management of the connection to the source of data in order to get or retrieve the data. This design pattern helps users to access what they are supposed to access. Real world example: There are applications that are used in the world today that make use of DAO. An example is Facebook which makes use of this design pattern to hide the working of the system in the background and present the users with a simple interface. Design pattern: Dispatcher pattern Classification: Design Problem: There is a problem when passing messages in a hierarchical model of software architectures that are found in the world today. There is a need to have a communication between the objects that are found in the same tier. Solution: The use of dispatcher pattern helps to send communication messages between objects which are found in the same tier. In the ANDC system, there will be the use of the same use cases like that of DAO. Consequences The dispatcher is a design pattern that is used to give the requests of the client to the proper party object that is found on the same level of tiers. The client requests are essential issues that come into play when designing the user interface and large programs. It is important to take care of requests from the client. Both data access object and dispatcher are two design patterns that deal with the users. They are design patterns that concern how the data and users will interact with the system. The difference between these two design patterns is that data access pattern is concerned with users and data. It is more concerned with the integrity of the data. This is unlike dispatcher which is tasked with how requests are handled. It is, therefore, more oriented to the user than the data or how the program operates (Papp 2001). Design pattern: Factory design pattern Classification: Design Problem: There is a problem of having the same collection of objects that can be instantiated together. There is a need to have a collection of these objects so that they can be instantiated together. Solution The solution to this problem is that similar objects will be collected and instantiated together. A design pattern that will undertake this process was designed. The actors that will be involved in the design include the customer, ANDC staff, and administrators. There are common tasks that will be undertaken by these groups. The diagram will include all the actors and use cases who will be involved in the process: Consequences: The third design pattern that will be used in this information system for ANDC is that of the factory design pattern. This design pattern is focused on creating a group of objects which are related due to instantiation. The objects are related a because of subclasses which are related. Compared with the data access object, they are both design patterns that are concerned with how objects relate to other objects, data access objects with the data and factory with the subclasses. The difference between these two design patterns is that the factory design pattern is tasked with subclasses and how they are related to the classes. On the other hand, data access patterns are tasked with how users will access the programming complexity. Dispatcher design pattern is tasked with ensuring that the requests of the users get access to the right tier. It is therefore tasked with the requests (Trauth & Howcroft 2005). Other design patterns which will be involved in the design process include: The model design pattern is tasked with models and the states of the functions. It shows how states are modeled and the functions that these models have. It is comparable to factory model. This is because this model shows the functions and how these functions are related and connected in the system. The factory design pattern is tasked with classes and they are related to the subclasses in that system. It is important to note that the two design patterns deal with how the system work. It is similar to DAO in that they are both concerned with the internal workings of the system. This not the case with many applications. The fifth pattern is view pattern. This design pattern was created so that the presentation layer can be analyzed and assessed. This is the same us data access object. This is because they are both concerned with how data are handled. The difference that comes with the use of this pattern is that it does not handle the data and the internal architecture of the system per se, but rather shows how they are presented. There is nothing major that is changed in this model. References Papp, R 2001, Strategic information technology: Opportunities for competitive advantage, Idea Group Inc., Pennsylvania. Trauth, EM & Howcroft, D 2005, Handbook of Critical information systems research, Edward Elgar. Read More