Introduction
Structured Analysis
Structured Design
Jackson Structured Development
Information Modeling Notations
A paradigm is simply a belief system (or theory) that guides the way we do things, or more formally establishes a set of practices. This can range from thought patterns to action.
Methodology refers to how you go about finding out knowledge and carrying out your research. It is our strategic approach, rather than our techniques and data analysis.
Object Oriented Methodology (OOM) is a system development approach encouraging and facilitating re-use of software components. With this methodology, a computer system can be developed on a component basis which enables the effective re-use of existing components and facilitates the sharing of its components by other systems.
This methodology employs international standard Unified Modeling Language (UML)from the Object Management Group (OMG). UML is a modeling standard for OO analysis and design which has been widely adopted in the IT industry.
Many types of OOM to use some of them are:
SA, SD, JSD SA/SD is easy to use where JSD is
complex
(Contd.)
In this method, the software system is initially split up into domains, which can then be broken down into subsystems to be analysed in depth.
The method provides comprehensive coverage for the analysis, design and implementation phases of the software development lifecycle.
Process are divided in following steps:1. Partition the system into domains 2. Analyse the application domain3. Verify the analysis through simulation4. Extract the requirements for the service
domain5. Analyse the service domains6. Specify the components of the architectural
domain7. Build the architectural components8. Translate the OOA models of each domain
using the architectural components
(Contd.)
The "goal of OOSD is to provide a single architectural design notation that can support every software design." (Wasserman)
It is not a method, but a notation to which methodological rules can be added. (Graham)
The main entities in OOSD are: 1. A system, which consists of a set of units,
which are either classes, modules or monitors.
2. A class, which can inherit from, and use other classes. A class contains public and private units, and can raise exceptions.
3. A module, which is either a data-object or an operation.
4. A monitor, which is used to define and use asynchronous processes.
(Contd.)
JSD was introduced by Michael Jackson in 1983.
The fundamental principle of JSD is that it focuses on describing the real world by the system i.e. its main focus is to map the progress in the real world rather than specifying the functions performed by the system.
JSD is and action related approach where SA/SD is based on Data flow.
The main entities in OOSD are: 1. Modeling Stage – This Stage comprises
of Entity Action and Entity Structure.2. Network Stage – Initial model step,
Function Step, and System Timing Step.3. Implementation Stage – Implementation
Step.
(Contd.)
In initial model step we concentrate on state vector and data stream communication.
A data stream is an unbounded queue where read operator extracts the next record from the queue, if there are no records when the process executing the read operation waits until the record is available whereas in write operation data stream places the next record in the
(Contd.)
Entity Action: the entities perform actions in time. The action is atomic and cannot be decomposed further.
Entity Structure: Step partially sequences the order of action with respect to time.
(Contd.)
Function step consist of pseudo code to the
output of action generated from states. In this step the developer requires a complete specification of the system.
System Timing Step relates with the
performance constraints of the system.
The implementation step focuses on process
scheduling and allocates the number of processors required. The process may be different form the processors
(Contd.)