1

00:00:07,170  -->  00:00:08,400
Hi there.

2

00:00:08,400  -->  00:00:09,290
Welcome back.

3

00:00:09,290  -->  00:00:17,070
And this is the little laugh courses and books typically use simple examples to explain object oriented

4

00:00:17,070  -->  00:00:23,490
concepts like inheritance polymorphism and deficits and so on which we're going to study in this course

5

00:00:23,490  -->  00:00:24,360
.

6

00:00:24,390  -->  00:00:28,740
These concepts are critical for developing well-designed applications.

7

00:00:28,740  -->  00:00:34,740
And my belief is that explaining such important concepts using simple examples may not be that helpful

8

00:00:34,860  -->  00:00:36,880
in truly understanding them.

9

00:00:36,960  -->  00:00:42,650
So even after learning the concepts in practice you may not be able to apply them in a proper way so

10

00:00:43,140  -->  00:00:49,800
to address this we're going to use it real world system as a case study to learn these concepts.

11

00:00:49,860  -->  00:00:55,680
The system is basically a social bookmarking application that we are developing here at semantics where

12

00:00:56,580  -->  00:00:58,880
the application is called trail dog.

13

00:00:59,030  -->  00:01:01,310
And that's also the user of the system.

14

00:01:01,590  -->  00:01:05,180
And we simply call it ask Chromeo are sometimes just true.

15

00:01:05,730  -->  00:01:12,000
It doesn't pre-alpha onstage that is it is mostly used only internally by our development team as we

16

00:01:12,000  -->  00:01:13,270
are still developing it.

17

00:01:13,680  -->  00:01:19,530
However it is already in decent shape with some architecture and also includes advanced algorithms from

18

00:01:19,530  -->  00:01:22,250
areas like search and data mining.

19

00:01:22,290  -->  00:01:27,710
Yesterday will also include few features that have not yet been developed but are on alert To-Do list

20

00:01:27,810  -->  00:01:28,810
.

21

00:01:28,820  -->  00:01:35,070
Initially we will look at a few basic features that should help us learn some of the concepts likker

22

00:01:35,150  -->  00:01:40,650
Rubinek or just a few more features and to build those features we need to understand more advanced

23

00:01:40,650  -->  00:01:45,940
concepts and advanced concepts to build those features.

24

00:01:45,970  -->  00:01:52,020
Finally the cool thing is that the project will be more or less an implementation of the custardy itself

25

00:01:52,020  -->  00:01:52,780
.

26

00:01:52,890  -->  00:01:57,740
So the nice thing about this whole process is that we have to study all the features.

27

00:01:57,780  -->  00:02:03,510
Then we learn all the concepts needed to implement those features and finally know what project we actually

28

00:02:03,570  -->  00:02:05,390
implement those features.

29

00:02:05,430  -->  00:02:07,430
This is why there is no context bitching.

30

00:02:07,470  -->  00:02:11,640
That is we are not learning one thing and implementing something else.

31

00:02:11,640  -->  00:02:16,380
Let me give you a shot them off the system.

32

00:02:16,380  -->  00:02:22,670
So what you're seeing here is the home page of the system and it shows all that recently bookmarked

33

00:02:22,740  -->  00:02:29,190
items by different users and it has three different sections and one of the sections says the articles

34

00:02:29,200  -->  00:02:29,370
.

35

00:02:29,670  -->  00:02:36,690
Which is basically the blinks that is there you also have pages that the users found interesting on

36

00:02:36,690  -->  00:02:40,220
how bookmarked So it shows some of the ramblings here.

37

00:02:40,410  -->  00:02:47,070
I Nitro's a site from which it has been downloaded so it is basically like any bookmarking website where

38

00:02:47,190  -->  00:02:53,560
you can bookmark web links you might have used Web sites like delicious or Dick sort or similar but

39

00:02:53,560  -->  00:03:00,390
those Web sites but it's not just the web links so it does more you or does more than these different

40

00:03:00,390  -->  00:03:02,140
Web sites into you.

41

00:03:02,220  -->  00:03:07,860
You can also bookmark movies and also books which are shown here.

42

00:03:08,150  -->  00:03:12,470
So these are the two different verticals that the system provides.

43

00:03:12,530  -->  00:03:19,620
You can bookmark items from these articles and in future we are also going to add restaurants doctors

44

00:03:19,620  -->  00:03:22,630
businesses and even something like recipes.

45

00:03:22,890  -->  00:03:28,330
So there are many other work because that can be included and like music.

46

00:03:28,410  -->  00:03:34,800
And we've all been including them so that's the homepage on me just start in using my Facebook account

47

00:03:34,800  -->  00:03:36,730
.

48

00:03:36,930  -->  00:03:44,030
I know I'm signed in and here it shows the articles the menu shows the articles books and movies.

49

00:03:44,220  -->  00:03:51,860
Let me just click on articles and here are all the bookmarks web that are how bookmarked.

50

00:03:52,260  -->  00:03:56,050
And here there are two sections of read and clues.

51

00:03:56,330  -->  00:04:03,840
So read ha ha 1176 on the wall 100 ramblings that are how much I can and you a higher on one hundred

52

00:04:03,840  -->  00:04:05,110
and fifty seven.

53

00:04:05,160  -->  00:04:11,140
And here is one of the ramblings and it can also have this little lock.

54

00:04:11,250  -->  00:04:19,200
It means that it is a pirate which means that other users can never see this particular item on each

55

00:04:19,310  -->  00:04:21,460
wabbling can also be archived.

56

00:04:21,780  -->  00:04:24,000
So we have some of these facts.

57

00:04:24,000  -->  00:04:25,370
That is the categories.

58

00:04:25,650  -->  00:04:31,260
So if I click on notations so I have all the articles related to and or visions.

59

00:04:31,440  -->  00:04:36,490
Similarly how books here and how movies.

60

00:04:36,780  -->  00:04:43,260
So here I have Roger on two hundred and six movies and I have another 71 under list.

61

00:04:43,620  -->  00:04:45,960
It's what we have here and we can also read them.

62

00:04:45,960  -->  00:04:48,080
There are three ratings within the system.

63

00:04:48,480  -->  00:04:50,160
We just call does like that.

64

00:04:50,190  -->  00:04:50,700
Loved it.

65

00:04:50,730  -->  00:04:51,680
And the best.

66

00:04:51,690  -->  00:04:57,990
So like that at least one and loved it as means that other user likes it more.

67

00:04:58,070  -->  00:05:02,540
It's a rating a ball like it and the best is like you know like a five star rating.

68

00:05:02,550  -->  00:05:05,210
So if I click on loved it here you know.

69

00:05:05,220  -->  00:05:08,460
So this particular item it got retired has loved it.

70

00:05:08,490  -->  00:05:15,500
So it just says loud but are wired non-fact on the best is taught in budo why it was the best.

71

00:05:15,570  -->  00:05:23,680
Now I can also Faktor these items by these ratings so if I click on the best it shows only the movies

72

00:05:23,680  -->  00:05:25,650
which I feel are the best.

73

00:05:25,660  -->  00:05:29,400
So these were rated as the best by me.

74

00:05:29,530  -->  00:05:35,280
So these are the movies and you how are we how books also.

75

00:05:35,470  -->  00:05:37,060
So this is my research right.

76

00:05:37,060  -->  00:05:40,040
These are the things this is like my gold mine.

77

00:05:40,030  -->  00:05:46,300
So these are the these are the things that I think that that interests me and I can always share it

78

00:05:46,300  -->  00:05:52,530
with my followers also so that they benefit from it from my research.

79

00:05:52,630  -->  00:06:01,890
And so that's the different monster that we can bookmark and within books you know let me add a bookmark

80

00:06:01,910  -->  00:06:02,080
.

81

00:06:02,290  -->  00:06:08,100
So we have indexed around 200000 most popular books from the web.

82

00:06:08,470  -->  00:06:14,460
So all these books in fact that database as my school database and all these books are also inside my

83

00:06:14,470  -->  00:06:15,070
school.

84

00:06:15,240  -->  00:06:19,450
However if I search for a book then my Asgill is not very efficient.

85

00:06:19,450  -->  00:06:26,710
So what we did was we indexed all of those books separately using the so large search library.

86

00:06:26,730  -->  00:06:33,610
So so our search library is specifically banned for searching for text items.

87

00:06:33,610  -->  00:06:40,630
So all that 200000 books have been extracted indexed separately by Saillard so large is an Apache library

88

00:06:40,870  -->  00:06:47,530
and it builds something called as an inverted index which is a specialized data structure that allows

89

00:06:47,550  -->  00:06:49,390
afast text searching.

90

00:06:49,390  -->  00:06:53,710
So when I search anything it's going to head the solar index itself.

91

00:06:53,890  -->  00:06:56,610
So let's just type in the book.

92

00:06:56,620  -->  00:07:00,150
But often they have to search.

93

00:07:00,280  -->  00:07:02,270
And here are a list.

94

00:07:02,500  -->  00:07:04,630
So this is coming from the search index.

95

00:07:04,840  -->  00:07:11,350
But let's say if the book was not on here then I can actually click here on this link and it would actually

96

00:07:11,980  -->  00:07:18,100
make a call to a third party system API which is from Greece which is also a very popular website.

97

00:07:18,430  -->  00:07:19,170
Hon sure.

98

00:07:19,180  -->  00:07:27,010
All the items that are fetched from that website and I can also add the book if I can find it there

99

00:07:27,030  -->  00:07:27,320
.

100

00:07:27,620  -->  00:07:30,800
And so let me just click on see here.

101

00:07:30,850  -->  00:07:37,590
So it's already saved into my account if I click here and say Here I can see that it is under red and

102

00:07:37,600  -->  00:07:39,910
I can also move it to reduce.

103

00:07:40,220  -->  00:07:40,640
That's it.

104

00:07:40,670  -->  00:07:42,120
Now it's under close.

105

00:07:42,310  -->  00:07:46,340
So that's how we read a book and movies are also ordered in the cemetery.

106

00:07:46,720  -->  00:07:54,400
Now coming to articles we can you know we can click on this plus I can paste you are directly here.

107

00:07:54,430  -->  00:07:57,660
I understand that the user interface is not really sleek.

108

00:07:57,670  -->  00:07:58,970
I'm really working on it.

109

00:07:59,140  -->  00:08:06,920
Megan said the whether it is plywood or not fly by default it gets added under the red section.

110

00:08:07,060  -->  00:08:16,270
But if I want to add at least I can do it here and I can also give the rating and attach some tag that

111

00:08:16,270  -->  00:08:20,890
is Katic I can categorize the book and I should just save it.

112

00:08:20,890  -->  00:08:28,870
So that's one way of adding web links but there is a nicer way to add web links if you if and if we

113

00:08:28,870  -->  00:08:30,460
go into the home page.

114

00:08:30,460  -->  00:08:35,130
So there is this Tinkler's install or bookmarklet and there is a link here.

115

00:08:35,140  -->  00:08:40,870
All we need to do is just click on this and drag it on to the browser and the button gets added.

116

00:08:40,870  -->  00:08:46,010
So you can see a button here called through lit and that's basically the bookmarklet.

117

00:08:46,180  -->  00:08:47,870
And how can it be helpful.

118

00:08:47,920  -->  00:08:49,420
Let's just see.

119

00:08:49,420  -->  00:08:54,040
So let's go to CNN.com and click on this link.

120

00:08:54,040  -->  00:08:56,410
How did Greece get into this mess.

121

00:08:56,410  -->  00:08:57,860
It's interesting.

122

00:08:58,390  -->  00:09:02,680
So this is the link now that say I'm finding this interesting.

123

00:09:02,680  -->  00:09:03,670
I want to market.

124

00:09:03,670  -->  00:09:06,020
I just click on this link Roulette.

125

00:09:06,550  -->  00:09:07,510
And there you go.

126

00:09:07,510  -->  00:09:15,730
It got added into my account so if I go back into my trilogy on if I click on articles it's right here

127

00:09:16,470  -->  00:09:17,080
that's it.

128

00:09:17,080  -->  00:09:22,810
That's how you add web links and movies and books already and through a database.

129

00:09:22,810  -->  00:09:23,460
So they are.

130

00:09:23,470  -->  00:09:27,220
I did that bookmark from within the system itself that has web links.

131

00:09:27,220  -->  00:09:32,180
They have to come from the back on soon we will be adding more articles.

132

00:09:32,200  -->  00:09:37,470
So the goal is that really will allow us to bookmark anything.

133

00:09:37,510  -->  00:09:41,370
So all your finds will be in one single place.

134

00:09:41,410  -->  00:09:43,170
So that's the nice thing about it.

135

00:09:43,280  -->  00:09:50,380
I know you can share all those winds with you or with your network with your followers and the cool

136

00:09:50,380  -->  00:09:55,350
feature that will be our thing very soon as a personalized recommendation engine.

137

00:09:55,360  -->  00:10:01,140
So based on what you how I did the system will automatically recommend you know stuff.

138

00:10:01,150  -->  00:10:03,450
So which would be more interesting to you.

139

00:10:03,490  -->  00:10:06,470
So to is something like what Amazon Dot Com does.

140

00:10:06,520  -->  00:10:10,510
Amazon also recommends your books based on what you have purchased in the past.

141

00:10:10,540  -->  00:10:14,600
So it's something like that and that's a shot them off to Leo