Design Patterns
What is a Design Pattern?
A design pattern solves a problem within a given context. The solution that is offered by implementing a pattern results in a system design structure, which balances the concerns of the design problem in a manner most appropriate for the given context. In “Understanding and Using Patterns in Software Development”, Dirk Riehle and Heinz Zullighaven offer a rather nice definition of what a design pattern is:
“A pattern is the abstraction from a concrete form which keeps recurring in specific non-arbitrary contexts.”
The ability to write good patterns is very difficult. A pattern should not only convey the facts about a system, but it should also tell a story about the system. It should allow the systems users to comprehend it, be able to customize it to accommodate new features.
Elements of a Design Pattern
A design pattern can be made up of the following components:
Name
The design pattern must have a meaningful name to allow a developer to use a single word or short phrase to reference the pattern.
Problem
The problem describes the patterns intent, the goal and objectives the pattern wants to achieve within the given context.
Context
The context of the pattern is the preconditions under which the problem and its solution seem to recur, and for which the solution is desirable.
Motivation
A description of the relevant forces/constraints and how they can interact/conflict with each other and the goals the pattern wishes to achieve.
Solution
The solution illustrates the structure of the pattern through UML diagrams, textual descriptions that include the patterns collaborations and participants.
Sample Example
One or more sample applications of the pattern which i...
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Learning Design Patterns
Michael Duell of AG Communication Systems presented a novel approach that may be adapted to introduce design patterns. He compares the theory behind design patterns to a real world model, illustrating the workings of the pattern implementation by giving trivial examples that a developer may be better able to relate to than the formal explanations offered by GoF or Holub for example.
When describing the Abstract Factory pattern, he uses the example of sheet metal stamping in an automobile company. The stamping equipment is an abstract factory, this creates the various car body parts. The same machinery is used to create right and left hand doors, right and left front fenders etc. By changing the stamping dies, the concrete classes produced by the machinery can be changed with minimal disruption to the whole process.
"Pattern amplifying machine; its neighborhoods are a way of measuring and expressing the repeated behavior of larger collectivities - capturing information about group behavior, and sharing that behavior with the group." (Johnson 2001:40)
conceptualization of the term/concept, and it also helps to show that the concept is indeed
Confluence: Lastly, I will have to forge my Confluence learning pattern because brainstorming will be the key to my success prior to writing this assignment. It will allow me to gather all of my information and notes from EXP 105 so that I can properly display what the Professor requires in the Week 5 paper assignment.
Software engineering is a relatively new career but the most important component of software engineering, the computer, has a long history that started many centuries ago. The abacus, a tool composed of beads and strings representing numbers, is considered by many to be the original computing device. The abacus, a device developed in Asia, was widely used during the Middle Ages. The abacus is still used today by many students. The next important milestone in the creation o...
Identify the theory, or theoretical framework, used for the study, and provide a short description of it.
The type of design pattern that I chose to further research falls under the Creational design pattern group. Creational Patterns are meant to solve problems that deals with object creation instruments, which means to create objects in a way that is appropriate for the specific circumstance.
Logical modeling deals with gathering system requirements and translating those requirements into a model. The logical model revolves around the requests of the business and system requirements. Logical modeling involves collecting information about business procedures, groups of data, and business units. After this information is assembled, diagrams and reports are produced including diagrams, business process diagrams, and eventually process flow diagrams. The diagrams created, should show the processes and data that exist, as well as t...
An analysis class can be classified into one of the three stereotypes, which are entity, boundary or control. An entity class is a class that the primary focus is to hold the data. Meanwhile, the boundary class is a class that the objects are used by the actors to communicate with the system. On the other hand, a control class is a class which provides coordinating behavior in the system. (Joey F. George, 2004)
Paradigms are belief systems that establish our actions patterns, practices and thoughts. Webster Dictionary defines paradigm as "an example or pattern: small, self-contained, simplified examples that we use to illustrate procedures, processes, and theoretical points." The most quoted definition of paradigm is Thomas Kuhn 's (1962, 1970) concept in The Nature of Science Revolution, paradigm as the underlying assumptions and intellectual structure upon which research and development in a field of inquiry is based. My understanding of Kuhn’s quote is that paradigms are a set of scientific theories that are well
Pattern recognition is when you look for similarities among and within small, decomposed problems that help solve complex problems more efficiently. An example of this would be drawing a dog, if we wanted to draw a dog we wouldn’t have to think too long because we know all dogs have 4 legs, eyes and a tail so knowing that it would make it easier and quicker to complete many different drawings. Finding patterns in problems makes problem solving a lot easier and it gives you a place to start when fixing a new problem. Pattern recognition is a process based on 5 key
All of these perspectives are known as paradigms, which are models or frameworks for questions that generate and guide research. They offer a framework for interpreting the results of studies and allow a set of assumptions to be
This is the simplest type of pattern, exactly like the desired casting. For making a mould, the pattern is accommodated either in cope or drag.
This is when the subject is encouraged when performing tasks that become increasingly similar to the task they are required to carry out. An example of an experiment that would provide evidence on this subject is explained by Jack Michael (1963), where a rat is trained to climb on top of an upside down can and drop a marble into a hole cut in the top of the can through the process of shaping. The process is split down into two sections; the first is training the rat to pick up and drop the marble and the second is training the rat to climb on top of the can. The rat would first of all be placed in a chamber with several marbles and would be rewarded when it showed signs of picking up and then dropping the marble. This would eventually lead to the rat learning to straight away pick up the marble and then drop it a little while later. After this the rat would be placed in the same chamber but this time with only the tin can and no marbles. A similar process would occur in that when the rat showed signs of climbing on top of the can it would be rewarded until it eventually learned to climb on the can. The two components of the task would then be combined and the rat would be placed in a chamber with both the marbles and the tin can. It would then learn to combine the tasks it had previously learned by being rewarded as it showed signs of taking the
With the rapid development and constant evolution of systems technology to date, different development processes have been established. Each of these processes where designed with a specific design in mind but we will find out that many of them share common tasks and are geared towards achieving the same goal
Explain in around 600 words, citing any literature you have consulted, what is meant by these terms in relation of object-oriented software design, and explain how they relate to the design you developed in your group.