Class: FileDataSource

Inherits:
Object
  • Object
show all
Defined in:
lib/repositories/data_sources/file_data_source.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data_transformer) ⇒ FileDataSource

Returns a new instance of FileDataSource.



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# File 'lib/repositories/data_sources/file_data_source.rb', line 10

def initialize(data_transformer)
  self.students = []
  self.seq_id = 1
  self.data_transformer = data_transformer
end

Instance Attribute Details

#data_transformer=(value) ⇒ Object

Sets the attribute data_transformer

Parameters:

  • value —

    the value to set the attribute data_transformer to.



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# File 'lib/repositories/data_sources/file_data_source.rb', line 8

def data_transformer=(value)
  @data_transformer = value
end

Instance Method Details

#add_student(student) ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 46

def add_student(student)
  student.id = seq_id
  students << student
  self.seq_id += 1
  student.id
end

#load_from_file(file_path) ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 16

def load_from_file(file_path)
  hash_list = data_transformer.str_to_hash_list(File.read(file_path))
  self.students = hash_list.map { |h| Student.from_hash(h) }
  update_seq_id
end

#paginated_short_students(page, count, existing_data_list = nil) ⇒ Object

Получить page по счету count элементов (страница начинается с 1)



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# File 'lib/repositories/data_sources/file_data_source.rb', line 32

def paginated_short_students(page, count, existing_data_list = nil)
  offset = (page - 1) * count
  slice = students[offset, count].map { |s| StudentShort.from_student(s) }

  return DataListStudentShort.new(slice) if existing_data_list.nil?

  existing_data_list.replace_objects(slice)
  existing_data_list
end

#remove_student(student_id) ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 58

def remove_student(student_id)
  students.reject! { |s| s.id == student_id }
end

#replace_student(student_id, student) ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 53

def replace_student(student_id, student)
  idx = students.find_index { |s| s.id == student_id }
  students[idx] = student
end

#save_to_file(file_path) ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 22

def save_to_file(file_path)
  hash_list = students.map(&:to_hash)
  File.write(file_path, data_transformer.hash_list_to_str(hash_list))
end

#sorted ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 42

def sorted
  students.sort_by(&:last_name_and_initials)
end

#student_by_id(student_id) ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 27

def student_by_id(student_id)
  students.detect { |s| s.id == student_id }
end

#student_count ⇒ Object 



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# File 'lib/repositories/data_sources/file_data_source.rb', line 62

def student_count
  students.count
end