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Software Design Patterns: How much do you understand?

2006-04-13T02:46:00.000+08:00

Actually i haven't gone to the lecture about this topic, so i was not really understand most of design pattern. since i studied in IVE so i have little memory about Bridge and Adapter Pattern

Bridge Pattern is used to provide multiple implementations under the same interface and it know as handle pattern.

Adapter Pattern is used to convert the interface of a class into another interface clients expect.
there are two adapter patters:

class adapter- use multiple inheritance to adapt one interface to another
object adapter- use single inheritance and delegation

Why do software projects fail so often?

2006-04-09T22:39:00.000+08:00

Among the most common factors:

- Unrealistic or unarticulated project goals
- Inaccurate estimates of needed resources
- Badly defined system requirements
- Poor reporting of the project's status
- Unmanaged risks
- Poor communication among customers, developers, and users
- Use of immature technology
- Inability to handle the project's complexity
- Sloppy development practices
- Poor project management
- Stakeholder politics
- Commercial pressures

http://www.spectrum.ieee.org/print/1685

What is test-driven development?

2006-04-06T01:05:00.000+08:00

1.What is the main idea of test-driven development?
Test-Driven Development (TDD) is a computer programming technique that involves writing test cases first and then implementing the code necessary to pass the tests.

2. What is the goal of test-driven development?
The goal of test-driven development is to achieve rapid feedback and implements the "illustrate the main line" approach to constructing a program.

http://en.wikipedia.org/wiki/Test-driven_development

3.How does a test-driven development cycle look like?

a.Write a test.
b.Run the test → It fails
c.As long as the test fails…
Improve functionality
Run the test
d.The test passes.
e.Refactor Code (Remove repeated information etc.)
http://www.stephankaemper.de/pic/test_rhythm_en.png

What makes a program code good?

2006-04-06T00:17:00.000+08:00

We should be consider the following factors to determine the program code is good or not.

Readability means what it says: that others can read your code. Readability means you bother to write comments, to follow conventions, and pause to name your variables wisely.

Layering means that internally, your program resembles a layer cake. The app sits on the framework sits on the OS sits on the hardware. Even within your app, you need layers, like file-document-view-frame. Higher layers call ones below, which raise events back up. (Calls go down; events go up.) Lower layers should never know what higher ones are up to.

Design means you take time to plan your program before you build it. Thoughts are cheaper than debugging. A good rule of thumb is to spend half your time on design.

Efficiency means your program is fast and economical. It doesn't hog files, data connections, or anything else. It does what it should, but no more. It loads and departs without fuss.

Clarity is the granddaddy of good programming, the platinum quality all the others serve.

http://msdn.microsoft.com/msdnmag/issues/04/07/EndBracket/

"YAGNI" , "JsUnit"

2006-03-24T00:20:00.000+08:00

YAGNI

In software engineering, YAGNI, short for 'You Ain't Gonna Need It', is a reminder for programmers that one should never add functionality until it is necessary. The temptation to write code that is not necessary at the moment, but is perceived to be necessary in the future, has some overlooked disadvantages:
Delays what the programmer was originally working on.
There is a chance that the requirements for the software will change and the functionality will become either different or unneeded. By applying the YAGNI principle, the programmer has not wasted time in adding the redundant functionality and no longer has to waste additional time debugging the code. The code is also less cluttered as a result.

reference:http://en.wikipedia.org/wiki/YAGNI

JsUnit

JsUnit is a Unit Testing framework for client-side (in-browser) JavaScript. It is essentially a port of JUnit to JavaScript. Also included is a platform for automating the execution of tests on multiple browsers and mutiple machines running different OSs. Its development began in January 2001.

reference:http://www.edwardh.com/jsunit/

Compare the CSDP with current Software Engineering course.

2005-11-20T01:56:00.000+08:00

According to the CSDP website, i found some areas that do not in our course.

I. Business Practices and Engineering Economics
A. Engineering Economics
B. Ethics
C. Professional Practice
D. Standards

II. Software Requirements
D. Software Requirements Specification
E. Requirements Validation
F. Requirements Management

III. Software Design
C. Software Design Quality Analysis and Evaluation
D. Software Design Notations and Documentation
E. Software Design Strategies and Methods
F. Human Factors in Software Design
G. Software and System Safety

IV. Software Construction
A. Construction planning
B. Code design
C. Data design and management
D. Error processing
E. Source code organization
F. Code documentationG. Construction QA
H. System integration and deployment
I. Code tuning
J. Construction tools

V. Software Testing
B. Test Levels
C. Testing Strategies
D. Test Design
E. Test Coverage of Code
F. Test Coverage of Specifications
G. Test Execution

VI. Software Maintenance
A. Software Maintainability
B. Software Maintenance Process
C. Software Maintenance Measurement
D. Software Maintenance Planning
E. Software Maintenance Management
F. Software Maintenance Documentation

VII. Software Configuration Management
C. Software Configuration Control
D. Software Configuration Status Accounting
E. Software Configuration Auditing

VIII. Software Engineering Management
A. Measurement
C. Initiation and Scope Definition
E. Software Acquisition
F. Enactment
G. Risk Management
H. Review and Evaluation

IX. Software Engineering Process
A. Process Infrastructure
B. Process Measurement
C. Process Definition
D. Qualitative Process Analysis
E. Process Implementation and Change

X. Software Engineering Tools and Methods
C. Maintenance Tools and Methods
D. Support Tools and Methods

XI. Software Quality
A. Software Quality Concepts
B. Planning for SQA and V&V
C. Methods for SQA and V&V
D. Measurement Applied to SQA and V&V

What is my favorite UML software?

2005-11-16T01:48:00.001+08:00

In the previous practical session, i tried to use two professional UML tools - "Poseidon" and "Eclipse" - to draw some simple UML diagrams.

After used these two tools, i prefer to use Eclipse for drawing UML digram, i feel that Eclipse is designed better than Poseidon. When i added a new class, i just need to mouse right-click add new class and also attributes.

On the other hand, it is more difficult when adding any class or attributes using Poseidon, you need to click the class icon once ,move the cursor back to the worksheet then click the mouse once more.

In that case, i would prefer to use Eclipse for draw UML diagram.

In the last year, i used Microsoft Visio XP to draw the UML digram, i felt that tool more easy to use than these two and the interface of Visio is quite similiar with the WindowsXP. Most of the operation is quite user friendly, user are only required click and drop the icon to the worksheet, class or actor have already created.

Basic software engineering skills?

2005-10-09T00:07:00.000+08:00

After i searched the information about software engineering in the internet, i made a summary that listed below:

1. SOFTWARE DESIGN

a. Engineers should have the ability to design systems that are readily adaptable to changing business needs;

b. Engineers should have the ability to understand, diagnose and recover from software failures.

c. They should have the ability to understand, diagnose and recover from software failures.

2. DEVELOPMENT PROCESSES

a. Software engineers must have the ability to assess software development risks and improve software development processes to reduce costs and produce more reliable systems.

b. Also they should have understanding of the development process issues related to improving maintainability and upgradeability of software in integrated systems.

3. SOFTWARE TECHNOLOGY

a. They need to provide any methods for efficiently representing data and techniques for efficiently operating upon data structures.

b. The structure, control, and design of software systems involving multiprocessing, distributed processing and network-centric computing.

4. PROBLEM SOLVING AND MILITARY APPLICABILITY

a. They need to have an exercising skills in problem formulation, criteria specification, analysis, design.

b. Clearly communicating the results of a project orally and in writing.

lee's weblog now open...

2005-10-03T10:41:00.000+08:00

Welcome to lee weblog,