Building applications for the cloud - presentation slides

Submitted by Kamal Wickramanayake on Tue, 11/17/2020 - 00:14

In 2011, I did two presentations for an ISACA seminar on cloud computing. The slides were on that site, but now the site has been replaced. The slides that I used had content still applicable and useful. So here you find the deck of slides I used for the first presentation.

Presentation title: Building applications for the cloud

Topics covered:

How to create the dependencies when the dependency injection pattern is used?

Submitted by Kamal Wickramanayake on Mon, 11/16/2020 - 23:43

In object oriented design of software, the dependency injection pattern (or inversion of control pattern – abbreviated as IoC pattern) is widely used to avoid key classes from instantiating their dependencies but to accept the dependencies from outside. Accordingly, the concern of object usage and the concern of object instantiation are separated. It is a case where "separation of concerns" is seen.

Difference between the Factory Method and Strategy design patterns

Submitted by Kamal Wickramanayake on Mon, 11/16/2020 - 22:06

Gang of Four (GoF) collection of design patterns talks about these patterns where the beginners sometimes fail to see the difference between. They often look at the code example of a pattern and attempt to guess what it is but fail to read through the details and understand the real intent of it. The Factory Method and Strategy patterns are coded similarly but with minor code differences. These minor code differences make the two patterns very different in the way they are used and the problems they solve. In this article, I describe these differences.

How to install Python on Linux?

Submitted by Kamal Wickramanayake on Mon, 11/09/2020 - 01:01

Python can easily be installed by using the package management software of the Linux distribution used.

In case of Ubuntu, "apt" command can be used as follows to install Python 3.8 from a terminal:

sudo apt install python3.8

Now, type "python3.8" in the terminal and the Python interactive shell should appear as follows:

Python interactive shell

ලිනක්ස් භාවිතා වන මෙහෙයුම් පද්ධතියක පයිතන් ඉන්ස්ටෝල් කරන්නේ කෙසේද?

Submitted by Kamal Wickramanayake on Mon, 11/09/2020 - 01:01

භාවිතා කරන ලිනක්ස් බෙදාහැරීමේ ඇති පැකේජ් මැනේජ්මන්ට් මෘදුකාංගය භාවිතා කොට පයිතන් පහසුවෙන් ඉන්ස්ටෝල් කළ හැක.

ඔබ භාවිතා කරනුයේ උබුන්ටු නම් "apt" විධානය පහත පරිදි ටර්මිනලයක භාවිතා කොට පයිතන් 3.8 ඉන්ස්ටෝල් කළ හැක:

sudo apt install python3.8

ඉන් පසුව ටර්මිනලයක "python3.8" යන්න ටයිප් කළහොත් පයිතන් ඉන්ටරැක්ටිව් ෂෙල් එක පහත දැක්වෙන අයුරින් දැක ගත හැකි වනු ඇත:

Python interactive shell