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diff --git a/usth/ICT2.7/P3L3 Design Patterns Subtitles/12 - Choosing a Pattern Quiz Solution - lang_en_vs4.srt b/usth/ICT2.7/P3L3 Design Patterns Subtitles/12 - Choosing a Pattern Quiz Solution - lang_en_vs4.srt deleted file mode 100644 index c348a2c..0000000 --- a/usth/ICT2.7/P3L3 Design Patterns Subtitles/12 - Choosing a Pattern Quiz Solution - lang_en_vs4.srt +++ /dev/null @@ -1,79 +0,0 @@ -1 -00:00:00,220 --> 00:00:01,750 -As we discussed in the class the right thing to - -2 -00:00:01,750 --> 00:00:05,050 -do here was to use the factory pattern. So here is - -3 -00:00:05,050 --> 00:00:07,910 -a possible code to solve the problem. Of course that there - -4 -00:00:07,910 --> 00:00:11,220 -are different possible solutions. So what we did for this code - -5 -00:00:11,220 --> 00:00:16,210 -was to first create a private, static, Singleton object called - -6 -00:00:16,210 --> 00:00:19,340 -instance, which is the one that will keep track of the - -7 -00:00:19,340 --> 00:00:22,250 -only instance that can be created on the class. Then we - -8 -00:00:22,250 --> 00:00:25,750 -define the default constructor, the constructor that doesn't take any parameter - -9 -00:00:25,750 --> 00:00:29,900 -as private. In this way other classes cannot create instances - -10 -00:00:29,900 --> 00:00:33,310 -of Singleton without calling our factory method, and finally we - -11 -00:00:33,310 --> 00:00:35,650 -create the factory method. And the factory method is very - -12 -00:00:35,650 --> 00:00:38,600 -simple. The method will first check whether an instance of - -13 -00:00:38,600 --> 00:00:40,970 -the class was already created. If it was created, it - -14 -00:00:40,970 --> 00:00:44,010 -would just return that instance. Otherwise, it will create a - -15 -00:00:44,010 --> 00:00:47,550 -new instance and assign it to that instance member variable - -16 -00:00:47,550 --> 00:00:50,960 -and then return the newly created instance. So with this code - -17 -00:00:50,960 --> 00:00:53,540 -you're guaranteed that other classes cannot bypass the factory - -18 -00:00:53,540 --> 00:00:56,530 -method, because the default constructor is private. And the that - -19 -00:00:56,530 --> 00:00:59,600 -the factory method will create one and only one instance - -20 -00:00:59,600 --> 00:01:02,020 -of the class, which is exactly what our requirements were. |