Agile Design

How can you design the software which is built in tiny increments?

How can you ensure that the software has a good structure which is flexible, maintainable and reusable?

ARE'NT YOU GOING TO MISS THE BIG PICTURE?

Not really! In an agile team, the big picture evolves along with the software.

How? With each iteration, the team improves the design of the system so that it is as good as it can be for the system as it is now. They focus on the current structure of the system, making it as good as it can be.

How do we know if the design of software is good?

Avoiding these following symptoms of poor design (design smells) should be a way.

1. Rigidity - The design is hard to change.
2. Fragility - The design is easy to break.
3. Immobility - The design is hard to reuse.
4. Viscosity - It is hard to do the right thing.
5. Needless Complexity - Overdesign
6. Needless Repetition - Mouse abuse
7. Opacity - Disorganized expression

These symptoms are similar in nature to code smells, but they are at a higher level. They are smells that pervade the overall structure of the software rather than a small section of code.

How to avoid design smells?

The principles of object-oriented design that help developers eliminate design smells and build the best designs for the current set of features.

1. SRP - The Single Responsibility Principle
2. OCP - The Open-Closed Principle
3. LSP - The Liskov Substitution Principle
4. DIP - The Dependency Inversion Principle
5. ISP - The Interface Segregation Principle

These principles are not the product of a single mind, but they represent the integration of the thoughts and writings of a large number of software developers and researchers.

Agile teams apply principles to remove smells. They don't apply principles when there are no smells.

Often, a design smell is caused by the violation of one or more of the principles.

Principles are not a perfume to be liberally scattered all over the system. Overconformance to the principles leads to the design smell of Needless Complexity.

Reference:
Image result for agile software development book

Image result for agile software development book

Robert C.Martin, Agile Software Development, Principles, Patterns, and Practices; Section 2, Agile Design.

Comments

Google I/O 2017 Notes

WOW! How meaningful this below video explains about the name of "I/O". Sundar Pichai talked a lot of Machine Learning Machine Learning is a very hot trend these days. Google uses it for their products. Google Assistant: Easily booking an online meal by talking with Google Assistant like a staff of partners, for example. Google Home: Hands-free calling. Google Photos: sharing suggestion, shared library, photo books and google lens. Youtube: 360 degree video, live stream. Kotlin became an official programming language for Android https://kotlinlang.org I'm on the way to Kotlin! ^^ Reference: [1]. https://www.youtube.com/watch?v=Y2VF8tmLFHw

JSF 2 - Dynamically manipulating the component tree with system events

Let's suppose we want to modify the metadata (attributes) of elements such as render , requried , maxlength but we do not define in JSF tags. The manipulating components can be conducted in Drools files, for example. How could we do? I think that is what we need to change something of component tree during JSF life-cycle. JSF supports event handling throughout the JSF life-cycle. In this post, I use two events: postAddToView for scanning components tree and preRenderView for manipulating the meta of components before rendering to GUI. I modified my own project from previous post for this example. This is my first further JSF trying out with the project as I said before. :) We define the tags f:event below the form - a container component of the components which we want to work on. The valid values for the attribute type for f:event can be found from tag library document of JSF 2. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" x...

BIRT - Fix the size of an image

I use a dynamic image as a logo my report in pdf. At the beginning, I use table to align the logo in left or right. I meet a problem with some images with a large width or height. My customer requires that the logo should be displayed in original size. These following steps solves my problem: 1. Use Grid instead of Table 2. Set Grid "Height" is 100% and "Width" is blank 3. Set "Fit to container" for images are "true". Download the the template here .

Styling Sort Icons Using Font Awesome for Primefaces' Data Table

So far, Primefaces has used image sprites for displaying the sort icons. This leads to a problem if we want to make a different style for these icons; for example, I would make the icon "arrow up" more blurry at the first time the table loading because I want to highlight the icon "arrow down". I found a way that I can replace these icons with Font Awesome icons. We will use "CSS Pseudo-classes" to achieve it. The hardest thing here is that we should handle displaying icons in different cases. There is a case both "arrow up" and "arrow down" showing and other case is only one of these icons is shown. .ui-sortable-column-icon.ui-icon.ui-icon-carat-2-n-s { background-image: none; margin-left: 5px; font-size: 1.1666em; position: relative; } .ui-sortable-column-icon.ui-icon.ui-icon-carat-2-n-s:not(.ui-icon-triangle-1-s)::before { content: "\f106"; font-family: "FontAwesome"; position: ...

Coders are NERDS | Learning English with Podcast

Let's learn three English vocabulary words based on real-life context through a humorous video about the life of software coders, especially at big tech companies when they work from home. Credit to Joma Tech. 🤓

vhandit

Search This Blog