# data-access-object.bsh
# 1.
class TransferObject
def data(key)
end
def set_data(key, value)
end
end
class TransferObjectDAO
def set_data_source(dataSource)
end
def create
end
def update(transfer_object)
end
def delete(transfer_object)
end
def find(id)
end
def find_all
end
end
class DataSource
def generate_next_id
end
def execute_command(command, param)
end
end
class TransferObjectDAOFactory
def transfer_object_dao
end
end
# 2.
class MyTransferObject < TransferObject
def initialize
@data = {}
end
def data(key)
@data[key]
end
def set_data(key, value)
@data[key] = value
end
def to_s
@data.to_s
end
end
class MyDataSource < DataSource
def initialize
@generated_id = 0
@objects = []
end
def generate_next_id
@generated_id = @generated_id + 1
end
def execute_command(command, param=nil)
result = nil
if(command == :insert)
result = (@objects << param)
elsif(command == :update)
index = @objects.index(param)
@objects.delete_at(index)
@objects.insert(index, param)
result = true
elsif(command == :delete)
result = (@objects.delete(param))
elsif(command == :find)
id = param
@objects.each do |transfer_object|
current_id = transfer_object.data("id")
if(current_id == id)
result = transfer_object
break
end
end
elsif(command == :find_all)
result = @objects
end
result
end
end
class MyTransferObjectDAO < TransferObjectDAO
def data_source=(data_source)
@data_source = data_source
end
def create
transfer_object = MyTransferObject.new
id = @data_source.generate_next_id
transfer_object.set_data("id", id)
@data_source.execute_command(:insert, transfer_object)
id
end
def update(transfer_object)
@data_source.execute_command(:update, transfer_object)
end
def delete(transfer_object)
@data_source.execute_command(:delete, transfer_object)
end
def find(id)
@data_source.execute_command(:find, id)
end
def find_all
@data_source.execute_command(:find_all)
end
end
class MyTransferObjectDAOFactory < TransferObjectDAOFactory
def initialize(data_source)
@data_source = data_source
end
def transfer_object_dao
transfer_object_dao = MyTransferObjectDAO.new
transfer_object_dao.data_source = @data_source
transfer_object_dao
end
end
# test - or business object, or client
dataSource = MyDataSource.new
factory = MyTransferObjectDAOFactory.new(dataSource)
dao = factory.transfer_object_dao
# create a new domain object
new_id = dao.create
# Find a domain object.
o1 = dao.find(new_id)
puts "o1: " + o1.to_s
# modify the values in the Transfer Object.
o1.set_data("address", "a1")
o1.set_data("email", "em1")
# update the domain object using the DAO
dao.update(o1)
puts "o1: " + o1.to_s
list = dao.find_all
puts "list before delete: " + list.join(', ')
# delete a domain object
dao.delete(o1)
puts "list after delete: " + list.join(', ')
