Factory Method Pattern
Description:
» The Factory Method pattern is a way of creating objects, but letting subclasses decide exactly which class to instantiate;» The Factory Method pattern is a lightweight pattern that achieves independence from application-specific classes. The client programs to the interface and lets the pattern sort out the rest.
Use When:
» Flexibility is important;» Objects can be extended in subclasses;
» There is a specific reason why one subclass would be chosen over another (this logic forms part of the Factory Method);
» A client delegates responsibilities to subclasses in parallel hierarchies.
//Define the Factory Object.
//The Factory class (object) defines the FactoryMethod() method, which decides which subclass to be instantiated.
public class Factory
{
public Product.IProduct FactoryMethod(int month)
{
if (month >= 4 && month <= 11)
{
return new Product.ProductA();
}
else if (month == 1 || month == 2 || month == 12)
{
return new Product.ProductB();
}
else
{
return new Product.ProductC();
}
}
}
//The Factory class (object) defines the FactoryMethod() method, which decides which subclass to be instantiated.
public class Factory
{
public Product.IProduct FactoryMethod(int month)
{
if (month >= 4 && month <= 11)
{
return new Product.ProductA();
}
else if (month == 1 || month == 2 || month == 12)
{
return new Product.ProductB();
}
else
{
return new Product.ProductC();
}
}
}
//Define the Factory Object.
//The Factory class (object) defines the FactoryMethod() method, which decides which subclass to be instantiated.
public class Factory
{
public Product.IProduct FactoryMethod(int month)
{
if (month >= 4 && month <= 11)
{
return new Product.ProductA();
}
else if (month == 1 || month == 2 || month == 12)
{
return new Product.ProductB();
}
else
{
return new Product.ProductC();
}
}
}
//The Factory class (object) defines the FactoryMethod() method, which decides which subclass to be instantiated.
public class Factory
{
public Product.IProduct FactoryMethod(int month)
{
if (month >= 4 && month <= 11)
{
return new Product.ProductA();
}
else if (month == 1 || month == 2 || month == 12)
{
return new Product.ProductB();
}
else
{
return new Product.ProductC();
}
}
}