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diff --git a/usth/ICT2.7/P2L2 OO Software Engineering and UML Subtitles/2 - Object Orientation Introduction - lang_en_vs5.srt b/usth/ICT2.7/P2L2 OO Software Engineering and UML Subtitles/2 - Object Orientation Introduction - lang_en_vs5.srt deleted file mode 100644 index 44fdd74..0000000 --- a/usth/ICT2.7/P2L2 OO Software Engineering and UML Subtitles/2 - Object Orientation Introduction - lang_en_vs5.srt +++ /dev/null @@ -1,187 +0,0 @@ -1 -00:00:00,390 --> 00:00:03,750 -Let's start with a quick introduction to object orientation and - -2 -00:00:03,750 --> 00:00:07,920 -the fundamental concepts behind it. And let's start by discussing what - -3 -00:00:07,920 --> 00:00:11,100 -exactly is object orientation? If you're younger than me, it - -4 -00:00:11,100 --> 00:00:13,700 -could be that the first programming language you learned was already - -5 -00:00:13,700 --> 00:00:17,030 -an object-oriented language. But things were not always like this. - -6 -00:00:17,030 --> 00:00:20,660 -Before object orientation became prevalent, people were not used to thinking - -7 -00:00:20,660 --> 00:00:23,447 -in terms of objects. So what happened afterwards? And what does - -8 -00:00:23,447 --> 00:00:25,727 -it mean to think in terms of objects and to follow - -9 -00:00:25,727 --> 00:00:28,583 -an object-oriented approach? First of all, it - -10 -00:00:28,583 --> 00:00:32,203 -means to give precedence of data over function. - -11 -00:00:32,203 --> 00:00:35,377 -Did items rather than functionality become the center - -12 -00:00:35,377 --> 00:00:39,020 -of development activities. This also allows for enforcing - -13 -00:00:39,020 --> 00:00:42,200 -the very important concept of information hiding, - -14 -00:00:42,200 --> 00:00:45,460 -which is the encapsulation and segregation of data - -15 -00:00:45,460 --> 00:00:49,710 -behind well-defined and ideally stable interfaces. In order - -16 -00:00:49,710 --> 00:00:51,490 -to be able to hide the design and - -17 -00:00:51,490 --> 00:00:54,130 -also implementation decisions. And note that the terms - -18 -00:00:54,130 --> 00:00:58,580 -encapsulation and information hiding are often used interchangeably, although - -19 -00:00:58,580 --> 00:01:01,270 -some people prefer to think of information hiding - -20 -00:01:01,270 --> 00:01:04,709 -as being the principle and encapsulation being the technique - -21 -00:01:04,709 --> 00:01:07,990 -to achieve information hiding. The key concept though, - -22 -00:01:07,990 --> 00:01:10,110 -no matter which term you use, is really to - -23 -00:01:10,110 --> 00:01:13,460 -gather, to seclude this data behind sort of - -24 -00:01:13,460 --> 00:01:16,610 -a wall and give access to the data only - -25 -00:01:16,610 --> 00:01:20,270 -through interfaces that you, the developer define. And why is - -26 -00:01:20,270 --> 00:01:22,800 -that important? Oh, for many reasons, and one of the main - -27 -00:01:22,800 --> 00:01:26,690 -ones is that it makes code more maintainable. Because the - -28 -00:01:26,690 --> 00:01:28,860 -rest of the code, the rest of the system doesn't have - -29 -00:01:28,860 --> 00:01:32,370 -to be concerned on how the implementation details or the - -30 -00:01:32,370 --> 00:01:37,220 -design are defined. And therefore, any change that happens behind this - -31 -00:01:37,220 --> 00:01:39,580 -wall doesn't concern the rest of the system. And, doesn't - -32 -00:01:39,580 --> 00:01:41,820 -affect the rest of the system, as long as you keep - -33 -00:01:41,820 --> 00:01:45,730 -your interfaces consistent. Another advantage of focusing on - -34 -00:01:45,730 --> 00:01:49,230 -objects and encapsulating the information into cohesive entities is - -35 -00:01:49,230 --> 00:01:52,130 -that it allows the reuse of object definitions - -36 -00:01:52,130 --> 00:01:55,000 -by incremental refinement. Which is what we normally call - -37 -00:01:55,000 --> 00:01:58,830 -inheritance. And inheritance is definitely a fundamental concept - -38 -00:01:58,830 --> 00:02:01,560 -in object orientation. For example, we can define a - -39 -00:02:01,560 --> 00:02:04,030 -car as a refinement of the vehicle. That there's - -40 -00:02:04,030 --> 00:02:06,850 -some additional characteristics with respect to a generic vehicle. - -41 -00:02:06,850 --> 00:02:11,220 -And then we can use the car wherever a vehicle can be used, which is what we - -42 -00:02:11,220 --> 00:02:14,200 -call polymorphism. And we'll continue this discussion for a - -43 -00:02:14,200 --> 00:02:16,440 -very long time. Because there's so many things that - -44 -00:02:16,440 --> 00:02:18,860 -could be discussed when we talk about object orientation, - -45 -00:02:18,860 --> 00:02:21,890 -its characteristics and its advantages. But in the interest - -46 -00:02:21,890 --> 00:02:24,000 -of time, let's for now just stop here. And - -47 -00:02:24,000 --> 00:02:27,020 -start talking about two key concepts in object orientation. |