Java Reference
In-Depth Information
The software development life cycle is a multistage process that includes requirements
specification, analysis, design, implementation, testing, deployment, and maintenance.
Key
Point
Developing a software product is an engineering process. Software products, no matter how
large or how small, have the same life cycle: requirements specification, analysis, design,
implementation, testing, deployment, and maintenance, as shown in Figure 2.3.
VideoNote
Software development process
Requirements
Specification
Input, Process, Output
IPO
System Analysis
System
Design
Implementation
Testing
Deployment
Maintenance
F
IGURE
2.3
At any stage of the software development life cycle, it may be necessary to go
back to a previous stage to correct errors or deal with other issues that might prevent the
software from functioning as expected.
Requirements specification
is a formal process that seeks to understand the problem that
the software will address and to document in detail what the software system needs to do.
This phase involves close interaction between users and developers. Most of the examples
in this topic are simple, and their requirements are clearly stated. In the real world, however,
problems are not always well defined. Developers need to work closely with their customers
(the individuals or organizations that will use the software) and study the problem carefully to
identify what the software needs to do.
System analysis
seeks to analyze the data flow and to identify the system's input and out-
put. When you do analysis, it helps to identify what the output is first, and then figure out what
input data you need in order to produce the output.
System design
is to design a process for obtaining the output from the input. This phase
involves the use of many levels of abstraction to break down the problem into manageable
components and design strategies for implementing each component. You can view each
component as a subsystem that performs a specific function of the system. The essence of
system analysis and design is input, process, and output (IPO).
Implementation
involves translating the system design into programs. Separate programs
are written for each component and then integrated to work together. This phase requires
the use of a programming language such as Java. The implementation involves coding, self-
testing, and debugging (that is, finding errors, called
bugs,
in the code).
requirements specification
system analysis
system design
IPO
implementation
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