Group 3

Homeworks/Answer.md

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+
+1.
+
+class CalculateSalary
+   def getter
+	# do something
+   end
+
+   def setter
+	# do something
+   end
+
+   def calculate_salary salary
+	if(salary.role == "manager"){
+		result = # do something with manager
+	}
+	else {
+		result = # do something with employee
+	}
+	result * (salary.rank + salary.working_day)
+   end
+
+   def export_to_document
+	# do something
+   end
+end
+
+
+class EmployeeSalary
+   attr_accessor :rank, :role, :working_day
+
+   def initalize *args
+
+   end
+end
+
+class ManagerSalary
+   attr_accessor :rank, :role, :working_day
+   def initialize *args
+
+   end
+end
+
+# violate S, O in SOLID
+Explain:
+	Class CalculateSalary co tren 1 ly do de thay doi: export, calculate
+	Nếu có thêm loại salary thì sẽ phải sửa hàm calculate của class CalculateSalary
+
+
+
+
+Solution:
+	Tao them 1 Class khác rieng cho viec export
+	Tao thêm 1 class Salary chung
+
+class Salary
+
+end
+
+class ExportSalary
+end
+
+class EmployeeSalary < Salary
+   attr_accessor :rank, :role, :working_day
+
+   def initalize *args
+     @rank = args[0]
+     @role = args[1]
+     @working_day = args[2]
+   end
+
+   def result
+   	result = # do something with employee
+   end
+end
+
+class ManagerSalary < Salary
+   attr_accessor :rank, :role, :working_day
+   def initialize *args
+	 @rank = args[0]
+     @role = args[1]
+     @working_day = args[2]
+   end
+
+   def result
+   	result = # do something with manager
+   end
+end
+
+
+class Salary
+	def initialize salary
+		@salary = salary
+	end
+	def get_result
+		@salary.result
+	end
+end
+
+
+class ExportSalary
+	def export
+		# do something to export
+	end
+end
+
+
+
+
+
+
+
+
+
+
+
+2.
+
+
+# Open/closed principle
+http://hg.openjdk.java.net/jdk6/jdk6/jdk/file/3d2f9f6b0f09/src/share/classes/java/io/
+
+class InputStream, FileInputStream, FilterInputStream, BufferInputStream thiet ke theo Decorator pattern()
+Theo decorator pattern:
+	Component: InputStream
+	Decorator: FilterInputStream
+	ConcreteComponents: AudioInputStream, ByteArrayInputStream, FileInputStream, FilterInputStream, InputStream ....
+	ConcreteDecorator: BufferedInputStream, CheckedInputStream, CipherInputStream, DataInputStream
+
+Tao ra Decorator FilterInputStream wrap Component InputStream. Dieu nay giup thuan loi khi can extend Component InputStream ma khong lam thay doi 	    Component.
+P/s: Em van chua hieu ro khac nhau run-time va compile-time cua inherit
+
+
+
+
+# Singple response principle
+https://github.com/wataridori/chatpp/blob/master/src/js/internals/Advertisement.js
+class Advertisement: chi dam nhan 1 nhiem vu ve advertisement, khong dam nhan cac chuc nang khac:
+	setUp
+	changeRandomAdvertisement
+	getAdvertisementText
+
+
+..... continue