Design Pattern - Structural - AbstractFactory

  

Scenario:

Create a Student factory to get student object by the school and department.

Solution:

This pattern provides to encapsulate individual factories.

Example: StudentFactory to create students based on the school and the department they study in

1. StudentFactory 



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namespace TestProject
{
    public interface IStudent
    {
        List<string> Courses();
    }

    public class UclaComputerScienceSchool : IStudent
    {
        public List<string> Courses()
        {
            return new List<string>() { "C#" };
        }
    }

    public class UclaMechanicalEngineeringSchool : IStudent
    {
        public List<string> Courses()
        {
            return new List<string>() { "Mechanics" };
        }
    }

    public class BoothFinanceSchool : IStudent
    {
        public List<string> Courses()
        {
            return new List<string>() { "StockMarkets" };
        }
    }
    public class BoothPolicySchool : IStudent
    {
        public List<string> Courses()
        {
            return new List<string>() { "Governance" };
        }
    }

    public abstract class StudentFactory
    {
        public abstract IStudent? GetStudent(string department);

        public static StudentFactory CreateStudentFactory(string school)
        {
            if (school.Equals("ucla", StringComparison.InvariantCultureIgnoreCase))
            {
                return new UclaStudentFactory();
            }
            else
            {
                return new BoothStudentFactory();
            }
        }
    }

    public class BoothStudentFactory : StudentFactory
    {
        public override IStudent? GetStudent(string department)
        {
            if (department.Equals("finance", StringComparison.InvariantCultureIgnoreCase))
            {
                return new BoothFinanceSchool();
            }
            else if (department.Equals("policy"))
            {
                return new BoothPolicySchool();
            }

            return null;
        }
    }

    public class UclaStudentFactory : StudentFactory
    {
        public override IStudent? GetStudent(string department)
        {
            if (department.Equals("computerscience", StringComparison.InvariantCultureIgnoreCase))
            {
                return new UclaComputerScienceSchool();
            }
            else if (department.Equals("mechanical"))
            {
                return new UclaMechanicalEngineeringSchool();
            }

            return null;
        }
    }
}



2. Create students and get courses they study in based on school and department they have picked.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 StudentFactory studentFactory = null; IStudent? student = null; studentFactory = StudentFactory.CreateStudentFactory("ucla"); Console.WriteLine($"Student's School is {studentFactory.GetType().Name}"); student = studentFactory.GetStudent("computerscience"); Console.WriteLine($"Student's Stream is {student.GetType().Name}"); var courses = student.Courses(); foreach (var course in courses) { Console.WriteLine($"Courses Taken:{course}"); } Console.ReadLine();